Fluidic diode valves for autonomous diagnostic assays

Abstract

A fluidic device, which may be a fluidic diode valve, incudes a source pad, a drain pad, and a flow controller. The source pad provides passive transportation of a fluid. The drain pad, which is located in spaced apart relation from the source pad, provides passive transportation of the fluid. The flow controller controls a flow of the fluid in a lateral direction from the source pad to the drain pad across a gap therebetween. Methods of using fluidic devices are also provided.

Description

FLUIDIC DIODE VALVES FOR AUTONOMOUS DIAGNOSTIC ASSAYSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application Number 63 / 522,850, filed 23 June 2023, and U.S. Provisional Patent Application Number 63 / 641 , 648, filed 2 May 2024, the disclosures of which are now expressly incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to fluidic diode valves and methods of using the valves in diagnostic assays.BACKGROUND

[0003] The development of rapid diagnostic tests has, in certain circumstances, alleviated the need to obtain test samples, send them to a centralized laboratory for analysis, and wait days or weeks for results. Instead, rapid diagnostic tests can be used at the point of care, or wherever the patient may be located, and they may provide results in only a few seconds or minutes.

[0004] Rapid diagnostic tests have achieved significant commercial success and also helped save lives of individuals that are cut off from traditional means of access to health care. However, the underlying technology behind the operation of these devices has not undergone significant changes since inception. With the recent advances made in microfluidic flow control and related technologies, there is opportunity to improve the technology behind the rapid diagnostic tests.BRIEF SUMMARY

[0005] The present disclosure provides fluidic diode valves and methods of using the valves I devices. In some embodiments, the disclosure provides a fluidic diode valve, comprising a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad. The fluidic diode valve also comprises a drain pad located in spaced apart relation from the source pad to form a gap therebetweenhaving a predetermined width and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad. Further, the fluidic diode valve comprises a flow controller configured to control a flow of the fluid in a lateral direction from the source pad to the drain pad across the gap therebetween. The flow controller comprises an inlet strip coupled to the bottom surface of the source pad and configured to temporarily pin the flow of the fluid from the source pad into the gap, a top outlet strip coupled to the top surface of the drain pad, a bottom outlet strip coupled to the bottom surface of the drain pad, and a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end that extends over a portion of the top surface of the source pad to bridge the gap between the source pad and the drain pad so that the flow of the fluid flows in the lateral direction along a flow surface of the connecting strip when the fluid is applied to the source pad. The top outlet strip cooperates with the bottom outlet strip to provide a capillary burst valve configured to prevent the flow of the fluid from flowing opposite the lateral direction back towards the source pad. In some embodiments, the top outlet strip extends partway into the gap between the source pad.

[0006] The present disclosure also provides a fluidic device comprising a first sorbent pad configured to provide passive transportation of a fluid, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a first gap therebetween and configured to provide passive transportation of the fluid, and a first flow controller configured to control a flow of the fluid in a lateral direction from the first sorbent pad to the second sorbent pad across the first gap therebetween. The first flow controller comprises an inlet strip coupled to a bottom surface of the first sorbent pad, a top outlet strip coupled to a top surface of the second sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the second sorbent pad to a second end that extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbentpad and the second sorbent pad so that the flow of the fluid flows in the lateral direction along a flow surface of the connecting strip that faces the first gap when the fluid is applied to the first sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the first sorbent pad. In some embodiments, the top outlet strip extends partway into the first gap between the first sorbent pad and the second sorbent pad. In some embodiments, the top and bottom outlet strips are at least flush with an outer edge of the second sorbent pad.

[0007] Additionally, the present disclosure provides a fluidic device comprising a center pad configured to provide passive transportation of a fluid, a first diode valve comprising a first source pad configured to provide passive transportation of a fluid, a first drain pad coupled to the center pad so that the first drain pad is located in spaced apart relation from the first source pad to form a first gap therebetween and the first drain pad configured to provide passive transportation of the fluid, and a first flow controller configured to control a flow of fluid from the first source pad to the first drain pad across the first gap therebetween, a second diode valve comprising a second source pad configured to provide passive transportation of the fluid, a second drain pad coupled to the center pad so that the second drain pad is located in spaced apart relation from the second source pad to form a second gap therebetween and the second drain pad configured to provide passive transportation of the fluid, and a second flow controller configured to control a flow of fluid from the second source pad to the second drain pad across the second gap therebetween, and a third diode valve comprising a third source pad coupled to the center pad and configured to provide passive transportation of the fluid, a third drain pad located in spaced apart relation from the third source pad to form a third gap therebetween and configured to provide passive transportation of the fluid, and a third flow controller configured to control a flow of fluid from the third source pad to the third drain pad across the third gap therebetween. Each of the first flow controller, the second flow controller, and the third flow controller comprises an inlet strip coupled to a bottom surface of the associated source pad, a top outlet strip coupled to a top surface of the associated drain pad, a bottom outlet strip iscoupled to a bottom surface of the associated drain pad opposite the top surface of the associated drain pad, and a connecting strip that extends from a first end coupled to the top outlet strip to a second end that extends over a portion of a top surface of the associated source pad to bridge the respective gap between the associated source pad and the associated drain pad so that the flow of fluid flows from the associated source pad to the associated drain pad along a flow surface of the connecting strip that faces the associated gap when a fluid is applied to the associated source pad. The top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing back towards the associated source pad. In some embodiments, the top outlet strip extends partway into the associated gap between the associated source pad and the associated drain pad.

[0008] The present disclosure also provides a method comprising providing a fluidic device comprising a first sorbent pad, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a first gap therebetween, and a first flow controller. The first flow controller comprises an inlet strip coupled to a bottom surface of the first sorbent pad, a top outlet strip coupled to a top surface of the second sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the second sorbent pad to a second end that extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad, wherein the top outlet strip extends partway into the first gap between the first sorbent pad and the second sorbent pad. The method also includes applying an amount of a first fluid to the first sorbent pad to cause a pressure within the first sorbent pad to exceed a capillary burst pressure to drive a portion of the amount of the first fluid from the first sorbent pad to the first end of the connecting strip of the first flow controller, transporting the first fluid in a lateral direction along a flow surface of the connecting strip of the first flow controller from the first sorbent pad to the second sorbent pad across the first gap to saturate the second sorbent pad with the first fluid, and preventing the first fluid from flowing opposite the lateral direction backtowards the first sorbent pad so that the first fluid only flows in the lateral direction from the first sorbent pad to the second sorbent pad.

[0009] The present disclosure provides a method comprising providing a fluidic device comprising a first sorbent pad, a second sorbent pad, and a first flow controller comprising an inlet strip, a top outlet strip, a bottom outlet strip, and a connecting strip extending between a first end and a second end spaced apart laterally from the first end, arranging the second sorbent pad in spaced apart relation from the first sorbent pad to form a first gap therebetween, coupling the bottom inlet strip of the first flow controller to a bottom surface of the first sorbent pad, coupling the top outlet strip of the first flow controller to a top surface of the second sorbent pad so that a portion of the top outlet strip extends partway into the first gap between the first sorbent pad and the second sorbent pad, coupling the bottom outlet strip of the first flow controller to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, and coupling the first end of the connecting strip of the first flow controller to the top outlet strip of the first flow controller on the second sorbent pad so that the second end of the connecting strip of the first flow controller extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad. In some embodiments, the first flow controller further comprises a base strip extending between a first end and a second end spaced apart laterally from the first end and the method further comprises coupling the first end of the base strip of the first flow controller to the bottom outlet strip of the first flow controller on the second sorbent pad and coupling the second end of the base strip of the first flow controller to the bottom inlet strip on the first sorbent pad so that the base strip of the first flow controller bridges the first gap between the first sorbent pad and the second sorbent pad.

[0010] The present disclosure provides a fluidic diode device comprising a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad. In some embodiments, the fluidic diode device also comprises a drain pad located in spaced apart relation from the source pad to form a gap therebetweenhaving a predetermined width and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad. In some embodiments, the fluidic diode device also comprises a flow controller arranged to extend between the source pad and the drain pad and configured to control a flow of the fluid in a lateral direction from the source pad to the drain pad across the gap therebetween. The flow controller is configured to allow the fluid to flow in the lateral direction from the source pad to the drain pad in response to a signal from a power source coupled to the fluidic diode device.

[0011] The present disclosure also provides a device comprising a power source, a printed circuit board electrically coupled to the power source, and a fluidic diode device integrated with the printed circuit board. In some embodiments, the fluidic diode device comprises a source pad, a drain pad, and a flow controller arranged to extend between the source pad and the drain pad and configured to control a flow of the fluid in a lateral direction from the source pad to the drain pad across a gap therebetween. The flow controller is configured to allow the fluid to flow in the lateral direction from the source pad to the drain pad in response to a signal from a power source coupled to the fluidic diode device.

[0012] The present disclosure also provides a method comprising providing a fluidic device comprising a source pad, a drain pad located in spaced apart relation from the source pad to form a gap therebetween, and a flow controller arranged to extend between the source pad and the drain pad. The method further comprises providing a power source electrically coupled to the flow controller. The method further comprises applying an amount of a fluid to the source pad that gets pinned at the source pad, sending a signal from the power source to the flow controller to de-pin the fluid to allow the flow of fluid to flow into the gap, transporting the fluid in a lateral direction from the source pad to the drain pad across the gap to saturate the drain pad with the fluid, and preventing the fluid from flowing opposite the lateral direction back towards the source padso that the fluid only flows in the lateral direction from the source pad to the drain pad.

[0013] The present disclosure also provides a fluidic diode valve comprising a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located in spaced apart relation to the source pad to form a gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and flow control means for transporting a flow of the fluid applied to the source pad in a lateral direction from the source pad to the drain pad across the gap therebetween to saturate the drain pad with the fluid while preventing the fluid from flowing opposite the lateral direction back towards the source pad so that the fluid only flows in the lateral direction from the source pad to the drain pad. In some embodiments, the flow control means comprises a bottom inlet strip coupled to the bottom surface of the source pad, a top outlet strip coupled to the top surface of the drain pad, a bottom outlet strip coupled to the bottom surface of the drain pad, a base strip that extends from a first end coupled to the bottom outlet strip on the drain pad to a second end coupled to the bottom inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a bottom side of the gap, and a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end coupled to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a top side of the gap so that the flow of the fluid flows in the lateral direction across the gap when the fluid is applied to the source pad. In some embodiments, the top and bottom outlets strips cooperate to provide a burst valve configured to prevent the flow of the fluid from flowing opposite the lateral direction back towards the source pad. In some embodiments, the top and bottom outlets strips are at least flush with an outer edge of the drain padand cooperate to provide a burst valve configured to prevent the flow of the fluid from flowing opposite the lateral direction back towards the source pad.

[0014] The present disclosure also provides a lateral flow assay device that may comprise the fluidic diode valve of some embodiments. The present disclosure also provides a vertical flow assay device that may comprise the fluidic diode valve of some embodiments.

[0015] The present disclosure also provides a fluidic device comprising a source pad located near the first end of the base strip and comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located near the second end of the base strip in spaced apart relation to the source pad to form a gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and a flow controller configured to control a flow of the fluid in only a lateral direction from the source pad to the drain pad across the gap therebetween.

[0016] The present disclosure also provides a fluidic device comprising a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a conjugate pad located in spaced apart relation to the source pad to form a first gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the conjugate pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the conjugate pad, a drain pad located in spaced apart relation to the conjugate pad to form a second gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and an absorbent pad located in spaced apart relation to the drain pad to form a third gap therebetween. The fluidic device further comprises a flow controller configured to control a flow of the fluid in only a lateral direction fromthe source pad to the conjugate pad across the first gap therebetween, from the conjugate pad to the drain pad across the second gap therebetween, and from the drain pad to the absorbent pad across the third gap therebetween.

[0017] Additionally, the present disclosure provides a method comprising providing a fluidic device comprising a first sorbent pad, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a gap therebetween, and a flow controller comprising an inlet strip coupled to a bottom surface of the first sorbent pad, a top outlet strip coupled to a top surface of the second sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, a base strip that extends from a first end coupled to the bottom outlet strip on the second sorbent pad to a second end coupled to the bottom inlet strip on the first sorbent pad to bridge the gap between the first and second sorbent pads on a bottom side of the gap, and a connecting strip that extends from a first end coupled to the top outlet strip on the second sorbent pad to a second end that extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad on a top side of the gap. The method further comprises applying an amount of a fluid to the first sorbent pad to cause a pressure within the first sorbent pad to exceed a capillary burst pressure to drive a portion of the amount of the first fluid from the first sorbent pad into the gap, transporting the first fluid in a lateral direction along a flow surface of the connecting strip and a flow surface of the base strip of the flow controller from the first sorbent pad to the second sorbent pad across the gap to saturate the second sorbent pad with the fluid, and preventing the first fluid from flowing opposite the lateral direction back towards the first sorbent pad so that the first fluid only flows in the lateral direction from the first sorbent pad to the second sorbent pad.

[0018] The present disclosure also provides a fluidic device comprising a first sorbent pad configured to provide passive transportation of a fluid, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a first gap therebetween and configured to provide passive transportation of the fluid, and a first flow controller configured to control a flow of the fluid in only alateral direction from the first sorbent pad to the second sorbent pad across the first gap therebetween. The first flow controller may comprise a bottom inlet strip coupled to a bottom surface of the first sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad, a top outlet strip coupled to a top surface of the second sorbent pad opposite of the bottom surface of the second sorbent pad, a base strip that extends from the bottom outlet strip on the second sorbent pad to the bottom inlet strip on the first sorbent pad to bridge the gap between the first sorbent pad and the second sorbent pad on a bottom side of the first gap, and a connecting strip that extends from the top outlet strip on the second sorbent pad to the top inlet strip on the first sorbent pad to bridge the gap between the first sorbent pad and the second sorbent pad on a top side of the first gap so that the flow of the fluid flows in the lateral direction across the gap when the fluid is applied to the first sorbent pad. The top outlet strip may cooperate with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the first sorbent pad. In some embodiments, the fluidic device further comprises a third sorbent pad located in spaced apart relation from the second sorbent pad to form a second gap therebetween and configured to provide passive transportation of the fluid and a second flow controller configured to control the flow of the fluid in only the lateral direction from the second sorbent pad to the third sorbent pad across the second gap therebetween. In some embodiments, the fluidic device may further comprise a fourth sorbent pad located in spaced apart relation from the third sorbent pad to form a third gap therebetween and configured to provide passive transportation of the fluid and a third flow controller configured to control the flow of the fluid in only the lateral direction from the third sorbent pad to the fourth sorbent pad across the third gap therebetween. The second and third flow controllers may each comprising a bottom inlet strip coupled to a bottom surface of the associated sorbent pad, a top outlet strip coupled to a top surface of the associated sorbent pad, a bottom outlet strip coupled to a bottom surface of the associated sorbent pad opposite the top surface of theassociated sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the associated sorbent pad to a second end that extends over a portion of the top surface of the associated sorbent pad to bridge the respective gap therebetween. In some embodiments, the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the associated sorbent pad. In some embodiments, the base strip extends from the bottom outlet strip on the fourth sorbent pad to the bottom inlet strip on the first sorbent pad to bridge the first, second, and third gaps.

[0019] The present disclosure also provides a fluidic device comprising a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a conjugate pad located in spaced apart relation to the source pad to form a first gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the conjugate pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the conjugate pad, a drain pad located in spaced apart relation to the conjugate pad to form a second gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, an absorbent pad located in spaced apart relation to the drain pad to form a third gap therebetween, and a flow controller configured to control a flow of the fluid in only a lateral direction from the source pad to the conjugate pad across the first gap therebetween, from the conjugate pad to the drain pad across the second gap therebetween, and from the drain pad to the absorbent pad across the third gap therebetween.

[0020] Finally, the present disclosure also provides a device comprising a paper based device comprising a sample pad and a fluidic diode valve comprising. The fluidic diode valve comprises a first sorbent pad comprising apaper material configured to provide passive transportation of a fluid, the first sorbent pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the first sorbent pad, a second sorbent pad located in spaced apart relation to the first sorbent pad to form a first gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the second sorbent pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the second sorbent pad, and a flow controller configured to control a flow of the fluid in only a lateral direction from the source pad to the drain pad across the first gap therebetween. The fluidic diode valve may be integrated with the sample pad of the paper based device so that the flow controller is configured to control the flow of fluid to the sample pad of the paper based device from the drain pad or from the sample pad of the paper based device to the source pad.

[0021] The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims of this application.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0022] A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:

[0023] FIG. 1 is a perspective view of a fluidic diode valve including a first pad - also referred to as a source pad - configured to provide passive transportation of a fluid, a second pad - also referred to as a drain pad - located in spaced apart relation from the first sorbent pad to form a gap therebetween and configured to provide passive transportation of the fluid, and a flow controller configured to control a flow of the fluid in a lateral direction L from the source pad to the drain pad across the gap, and further showing the flow controller includes, an inlet strip coupled to a bottom surface of the source pad, a top outlet strip coupled to a top surface of the drain pad, a bottom outlet strip coupled to a bottom surface of the drain pad, a base strip that extends from a first end coupled to the bottom outlet strip on the drain pad to a second end coupled tothe bottom inlet strip on the source pad to bridge the air gap between the source pad and the drain pad on a bottom side of the air gap, and a connecting strip that extends from a first end coupled to the top outlet strip on the drain pad to a second end that extends over or overhangs a portion of the top surface of the source pad to bridge the air gap between the source pad and the drain pad on a top side of the air gap so that the flow of the fluid flows in the lateral direction L along flow surfaces of the connecting strip and the base strip when the fluid is applied to the source pad;

[0024] FIG. 1 A is a side view of the fluidic diode valve of FIG. 1 showing an amount of fluid being added to the source pad;

[0025] FIG. 1 B is a view similar to FIG. 1 A showing the bottom inlet strip temporarily pins the flow of the fluid from flowing the source pad into the gap;

[0026] FIG. 1 C is a view similar to FIG. 1 B showing the flow of the fluid flows in the lateral direction L along the flow surfaces of the base strip and the connecting strip across the air gap once the critical pressure at the fluid front is reached, and showing the top outlet strip extends partway into the gap between the source pad and the drain pad and cooperates with the bottom outlet strip to provide a capillary burst valve that prevents the fluid from flowing opposite the lateral direction L back towards the source pad;

[0027] FIG. 2 is an exploded view of the fluidic diode valve of FIG. 1 showing the fluidic diode valve includes the source pad, the drain pad, and the flow controller having the base strip, the bottom inlet strip configured to be coupled to the base strip and the bottom surface of the source pad, the top outlet strip configured to be coupled to the top surface of the drain pad, a bottom outlet strip coupled to the base strip and the bottom surface of the drain pad, and the connecting strip having one end configured to be coupled to the top outlet strip and a second end configured to extend over part of the source pad;

[0028] FIGS. 3A-C show the gap between the source pad and the drain pad and / or the distance between the bottom inlet strip and the top outlet strip may be varied to control the amount of time the flow of fluid is temporarily pinned at the bottom inlet strip;

[0029] Fig. 4 is a perspective view of another embodiment of a fluidic diode valve showing the second end of the connecting strip included in the flow controller is directly coupled to the source pad with a top inlet strip included in the flow controller instead over overhanging the source pad like in the embodiment of FIG. 1 ;

[0030] FIG. 5A is a perspective view of another embodiment of a fluidic diode valve showing the flow controller further includes protrusions that extend from the flow surface of the connecting strip into the gap between the source pad and the drain pad so as to help control the timing of the flow of fluid from the source pad to the drain pad;

[0031] FIG. 5B is a side view of the fluidic device of FIG. 5A showing the protrusions are spaced apart laterally at a predetermined distance and each protrusion has a predetermined height;

[0032] FIG. 5C is a bottom view of the fluidic device of FIG. 5A with the base strip removed showing each protrusion extends longitudinally across the connecting strip between outer edges of the connecting strip;

[0033] FIG. 6A is a perspective view of another embodiment of a fluidic device showing the device includes cascaded diode valves each including a source pad, a drain pad, which becomes the source pad for the adjacent pad, and a flow controller that controls the flow of fluid in the lateral direction L from each valve to the next valve in the cascade;

[0034] FIG. 6B is a side view of the fluidic device of FIG. 6A showing each flow controller includes a bottom inlet strip coupled to a bottom surface of the first sorbent pad, a top outlet strip coupled to a top surface of the subsequent sorbent pad, and a connecting strip that extends between adjacent sorbent pads to bridge the respective gap therebetweeen, and further showing the flow controllers for each valve share a base strip that extends between each of the sorbent pads;

[0035] FIG. 6C is a top view of the fluidic device of FIG. 6A showing each top outlet strip extends partway into the gap between the source pad and the drain pad so that the outer end of the top outlet strip is located in the gap;

[0036] FIG. 7 is a perspective view of a cascaded diode valve integrated into with a lateral flow assay (LFA) to provide a lateral flow device sheet that may be segmented into smaller lateral flow devices;

[0037] FIG. 8 is a perspective view of another lateral flow device integrated with the cascaded diode valves with a paper bridge configured to link the cascaded diode valves with the lateral flow assay;

[0038] FIG. 9 is a perspective view of another lateral flow device similar to the lateral flow device of FIG. 8;

[0039] FIG. 10A is a perspective view of another embodiment of a fluidic device showing the cascaded diode valves may be integrated into a vertical flow assay (VFA) format;

[0040] FIG. 10B is a detail view of FIG. 10A showing the fluidic device includes a modified diode valve section in the series of cascaded diode valves that allows vertical flow through a membrane member included in the modified diode valve section;

[0041] FIG. 10C is an exploded view of the fluidic device of FIG. 10A showing the modified section includes first and second sorbent pads coupled to a base pad so that the second sorbent pad is spaced apart from the first sorbent pad to define the gap therebetween and a flow controller configured to controls the flow of the fluid in the lateral direction L into the gap;

[0042] FIG. 10D is a detail view of FIG. 10C showing the flow controller includes an bottom inlet strip, a top outlet strip, a connecting strip, and a membrane member coupled to the base pad in the gap so that the membrane member is located between the first and second sorbent pads to allow vertical flow through the membrane member into the base pad;

[0043] FIG. 11 is a perspective view of another embodiment of a fluidic diode valve showing the bottom inlet strip comprises an electrically conductive material and the fluidic device includes a power source electrically coupled to the bottom inlet strip so as to send a signal to the bottom inlet strip to cause the flow of fluid to flow in the lateral direction L into the gap;

[0044] FIG. 11 A is a side view of the fluidic diode valve of FIG. 11 showing an amount of fluid being added to the source pad with the power source in an off mode;

[0045] FIG. 11 B is a view similar to FIG. 11 A showing the bottom inlet strip temporarily pins the flow of the fluid from flowing the source pad into the gap;

[0046] FIG. 11 C is a view similar to FIG. 11 B showing the power source has been changed to an on mode to cause the power source to send the signal to the bottom inlet strip to cause or allow the flow of fluid to flow in the lateral direction L into the gap;

[0047] FIG. 12 is a top view of another embodiment of a modular fluidic device that includes multiple fluidic diode valves with different time delays;

[0048] FIG. 13 is a perspective view of another embodiment of a modular fluidic device;

[0049] FIG. 14 is a perspective view of another embodiment of a fluidic diode valve showing the including a source pad, a drain pad, and a flow controller configured to control a flow of the fluid in a lateral direction L from the source pad to the drain pad across the gap, and further showing the flow controller includes top and bottom inlet strips coupled to the source pad so that the temporary pinning of the fluid at the source pad is inverted compared to the embodiment of FIG. 1 , top and bottom outlet strips coupled to drain pad, a base strip that extends between the source and drain pad to bridge the gap on a bottom side of the gap, and a connecting strip that extends between the source and drain pad to bridge the gap on a top side of the gap so that the flow of the fluid flows in the lateral direction L through the gap when the fluid is applied to the source pad;

[0050] FIG. 14A is a side view of the fluidic diode valve of FIG. 14 showing an amount of fluid being added to the source pad;

[0051] FIG. 14B is a view similar to FIG. 14A showing the top inlet strip that extends into the gap temporarily pins the flow of the fluid from flowing the source pad into the gap;

[0052] FIG. 14C is a view similar to FIG. 14B showing the flow of the fluid flows in the lateral direction L along the flow surfaces of the base strip and theconnecting strip across the gap once the critical pressure at the fluid front is reached;

[0053] FIG. 15 is a side view of another embodiment of a fluidic diode valve showing the flow controller includes magnetic strips each coupled to a bottom surface of the base strip on opposite ends and conductive strips that each extend around the base strip and the magnetic strip and the fluidic device further includes a printed circuit board configured to be coupled to the conductive strip so as to send a signal to the flow controller to cause the flow of fluid to flow in the lateral direction L into the gap;

[0054] FIG. 15A is a side view of the fluidic diode valve of FIG. 15 showing an amount of fluid has been added to the source pad such that the top inlet strip that extends into the gap temporarily pins the flow of the fluid from flowing from the source pad into the gap;

[0055] FIG. 15B is a view similar to FIG. 15A showing the signal has been applied to allow the pinned liquid to spread;

[0056] FIG. 15C is a view similar to FIG. 15B showing that once the amount of pinned liquid grows in height to contact the flow surface of the connecting strip, the capillary forces pull the fluid through the gap to the drain pad;

[0057] FIG. 16A is a diagrammatic side view of an electroactive fluidic diode device configured to form a stop valve that would effectively pin the fluid meniscus when no voltage is applied like as shown in FIG. 16B and de-pins with a rapid response time upon the application of the potential to the electrodes as shown in FIG. 16C;

[0058] FIG. 16B is a diagrammatic side view of an electroactive fluidic diode device showing enhanced pinning of the fluid at the source pad during an OFF state / mode in which the switch is open;

[0059] FIG. 16C is a diagrammatic side view of an electroactive fluidic diode device showing enhanced de-pinning of the fluid at the source pad during an ON state / mode in which the switch is closed;

[0060] FIG. 17 is a diagrammatic view of the electroactive fluidic diode device of FIG. 16A showing application of a pulse width modulated (PWM) signal to the fluidic diode device for sensing and actuation of the fluid flow;

[0061] FIG. 17A is a diagrammatic view of the electroactive fluidic diode device of FIG. 17 showing a sensing signal being applied to the electrodes of the electroactive fluidic diode device and the signal read by the microcontroller being an open circuit voltage;

[0062] FIG. 17B is a diagrammatic view of the electroactive fluidic diode device of FIG. 17A showing the fluid pinned at the ledge strip, contacting the drain electrode such that the circuit is no longer an open circuit and the appearance of an effective impedance across the contacts of the fluidic diode would reduce the voltage signal being read by the microcontroller which indicates an actuation signal is ready to be applied;

[0063] FIG. 17C is a diagrammatic view of the electroactive fluidic diode device of FIG. 17B showing the actuation signal has been applied to de-pin the fluid at the ledge strip so that the fluid flows across the air gap to the drain pad which causes the capacitance to increase (manifesting as an increase in the voltage signal read across the electrodes by the microcontroller) as the fluid flows over a greater surface area of the drain electrode thereby increasing the overall impedance across the electrodes of the fluidic diode;

[0064] FIG. 17D is a diagrammatic view of the electroactive fluidic diode device of FIG. 17C showing all the fluid in the gap has flowed to the drain pad so that the fluid dewets within the gap thereby disconnecting the drain electrode, reverting the potential measured by the microcontroller across the electrodes back to the open circuit voltage so that a user can ascertain the location of the fluid in the device;

[0065] FIG. 18 is an exploded perspective view of a cascaded electroactive fluidic diode assembly that may be segmented or cut into single electroactive fluidic diode strips like as suggested in FIG. 41 ;

[0066] FIG. 19 is a top and bottom perspective view of a single electroactive fluidic diode strip cut from the cascaded electroactive fluidic diode assembly of FIG. 18;

[0067] FIG. 20A is a top view of a printed circuit board (PCB) configured to be integrated with the single diode device of FIG. 18;

[0068] FIG. 20B is a diagrammatic view showing the schematic of the printed circuit board of FIG. 20A;

[0069] FIG. 21 is a top view of the printed circuit board of FIG. 20A before being integrated with the electroactive fluidic diode strip of FIG. 19 showing Neodymium magnets coupled to the bottom of the printed circuit board and copper tape clad magnets coupled to the top so that the electroactive fluidic diode strip makes electrical contact with the underlying contact pads on the printed circuit board;

[0070] FIG. 22 is a top view of the printed circuit board of FIG. 20A after being integrated with the electroactive fluidic diode strip of FIG. 19 showing the electroactive fluidic diode strip in the ON state / mode in which the voltage has been applied to the contact pad to de-pin the solution and allow the solution to spread to the drain pad, and further showing the one of the LED light indicates which part of the electroactive fluidic diode strip has been activated;

[0071] FIG. 23 is a view similar to FIG. 22 after the solution has been depinned and allowed to flow to the drain pad;

[0072] FIG. 24A is a diagrammatic side view of an electronically gated fluidic diode device showing the dimensions of the different components of the electronically gated fluidic diode device;

[0073] FIG. 24B is view similar to FIG. 24A showing the dimensions of the different components of the electronically gated fluidic diode device;

[0074] FIG. 25 is a perspective view of another embodiment of a fluidic diode valve showing the including a source pad, a drain pad, and a flow controller configured to control a flow of the fluid in a lateral direction L from the source pad to the drain pad across the gap, and further showing the source pad extends past the edges of the top and bottom inlet strips into the gap so that there is seamless fluid flow into the gap without pinning of the fluid at the source pad;

[0075] FIG. 25A is a side view of the fluidic diode valve of FIG. 25 showing an amount of fluid being added to the source pad;

[0076] FIG. 25B is a view similar to FIG. 25A showing there is no pinning of the fluid at the source pad;

[0077] FIG. 25C is a view similar to FIG. 25B showing the flow of fluid flows seamlessly to the drain pad;

[0078] FIG. 26A is a perspective view of another embodiment of a fluidic diode valve showing the flow controller of the fluidic diode valve may further include connecting side strips coupled to the outer edges of the source pad and the drain pad to at least partially close the air gap between the source pad and the drain pad on the sides of the device;

[0079] FIG. 26B is an partially exploded view of the fluidic diode valve of FIG. 26A showing the connecting side strips are configured to be coupled to the respective outer edge of the source and drain pads with inlet and outlet side strips;

[0080] FIG. 27 is a side view of a lateral flow assay device incorporating a fluidic diode valve like as shown in FIG. 23;

[0081] FIG. 27A-I are top views of the lateral flow assay device of FIG. 27 showing the steps of using the lateral flow assay device;

[0082] FIG. 28 is a side view of another embodiment of a lateral flow assay device showing the lateral flow assay may further include a filter arranged vertically above the sample pad with a vertical gap therebetween and a vertical flow controller arranged between the filter and the sample pad to control a flow of the sample in a vertical direction from the filter to the sample pad across the vertical gap therebetween to prevent the sample from flowing opposite the vertical direction back towards the filter;

[0083] FIG. 28A is a detail view of the filter and vertical flow controller included in the lateral flow assay device of FIG. 28;

[0084] FIG. 29 is a perspective view of another lateral flow assay device incorporating a fluidic diode valve like as shown in FIG. 23 in which the fluid diode valve is coupled to a lateral flow sample pad at a right angle;

[0085] FIG. 30 is a perspective view of another lateral flow assay device incorporating an electroactive fluidic diode like as shown in FIG. 16A in which the fluidic diode valve is coupled to the sample pad so that the sample pad is the drain pad of the fluidic diode valve;

[0086] FIG. 31 is a perspective view of another lateral flow assay device incorporating an electroactive fluidic diode like as shown in FIG. 16A in which the fluidic diode valve is coupled to the sample pad so that the sample pad is the source pad of the fluidic diode valve;

[0087] FIG. 32 is a perspective view of another fluidic diode valve integrated into a vertical flow assay (VFA) format;

[0088] FIG. 33 is a side view of the fluidic diode valve of FIG. 32 showing the flow direction of the fluid;

[0089] FIG. 34 is a diagrammatic side view of a fluidic diode device;

[0090] FIG. 35 is a top view of a cascaded fluidic diode device; and

[0091] FIG. 36 is a perspective view of a person cutting the electroactive fluidic diode strips.DETAILED DESCRIPTION

[0092] Various embodiments are described below with reference to the drawings in which like elements generally are referred to by like numerals. The relationship and functioning of the various elements of the embodiments may better be understood by reference to the drawings and the following detailed description. However, embodiments are not strictly limited to those illustrated in the drawings or described below.

[0093] Examples of methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present disclosure. All publications, patent applications, patents and other reference materials mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.

[0094] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control.

[0095] An illustrative fluidic device 20 is shown in FIG. 1. In the illustrative embodiment, the fluidic device 20 is a single diode valve configured to control the flow of a fluid in a lateral direction L as shown in FIGS. 1 A-C.

[0096] The fluidic device 20 includes flow control means for transporting a flow of the fluid in the lateral direction L from a source pad 22 to a drain pad 24 across an air gap 28 formed therebetween to saturate the drain pad 24 with the fluid while preventing the fluid from flowing opposite the lateral direction L back towards the source pad 22 so that the fluid only flows in the lateral direction L from the source pad 22 to the drain pad 24 as shown in FIGS. 1 A-C. The flow controller 26 prevents the fluid in the drain pad 24 or the fluid that is applied to the drain pad 24 from flowing opposite the lateral direction L back to the source pad 22.

[0097] The device 20 includes a first pad 22, a second pad 24, and a flow controller 26 as shown in FIG. 1 . Both the first pad 22 - also referred to as the source pad - and the second pad 24 - also referred to as the drain pad - are configured to provide passive transportation of the fluid. The drain pad 24 is located in spaced apart relation from the source pad 22 to form a gap 28 or an air gap 28 therebetween. The flow controller 26 is configured to control the flow of the fluid in the lateral direction L from the source pad to the drain pad across the gap 28.

[0098] The flow controller 26 provides the flow control means for transporting the flow of the fluid in the lateral direction L across the air gap 28 while preventing the flow of fluid from flowing opposite the lateral direction L back towards the source pad 22 from the drain pad 24. The flow controller 26 prevents the fluid in the drain pad 24 from flowing opposite the lateral direction L back towards the source pad 22 from the drain pad 24. In other words, the flow controller 26 prevents fluid in the drain pad 24 or fluid that is applied to the drain pad 24 from flowing opposite the lateral direction L back to the source pad 22.

[0099] The flow controller 26 includes a base strip 21 , a bottom inlet strip 30, a top outlet strip 32, a bottom outlet strip 36, and a connecting strip 34 as shown in FIGS. 1-2. The bottom inlet strip 30 is coupled to a bottom surface 22BS of the source pad 22. The top outlet strip 32 is coupled to a top surface 24TS of the drain pad 24 and extends partway into the gap 28 between the source pad 22 and the drain pad 24. The bottom outlet strip 36 is coupled to a bottom surface 24BS of the drain pad 24. Both the base strip 21 and the connecting strip 34extend between the source pad 22 and the drain pad 24 on top and bottom sides of the source pad 22 and the drain pad 24 to bridge the air gap 28 therebetween as shown in FIGS. 1-1C.

[0100] The base strip 21 extends from a first or outlet end 210 coupled to the bottom outlet strip 36 on the drain pad 24 to a second or inlet end 211 coupled to the bottom inlet strip 30 on the source pad 22 to bridge the air gap 28 between the source pad 22 and the drain pad 24 on a bottom side of the air gap 28 as shown in FIGS. 1-2. The connecting strip 34 extends from a first or outlet end 340 coupled to the top outlet strip 32 on the drain pad 24 to a second or inlet end 34I that extends over or overhangs the top surface 24TS of the source pad 22 to bridge the gap 28 between the source pad 22 and the drain pad 24 on a top side of the air gap 28 as shown in FIGS. 1 -2. In this way, the fluid flows in the lateral direction L along a flow surface 34S of the connecting strip 34 and a flow surface 21S of the base strip 21 that face the gap 28 when the fluid is applied to the source pad 22 as shown in FIGS. 1A-C.

[0101] The bottom inlet strip 30 temporarily pins the flow of the fluid from the source pad 22 into the gap 28, while the top and bottom outlet strips 32, 36 cooperate to provide a burst valve or capillary burst valve that prevents the fluid from flowing opposite the lateral direction L back towards the source pad 22 as shown in FIGS. 1 A-C. The top outlet strip 32 cooperates with the bottom outlet strip 36 to prevent the fluid in the drain pad 24 from flowing opposite the lateral direction L back towards the source pad 22 as shown in FIGS. 1A-C. The top outlet strip 32 and the bottom outlet strip 36 thereby provide a burst valve or capillary burst valve that prevents the fluid from flowing opposite to the desired direction L so that the device 20 may be integrated into existing lateral flow assay formats, vertical flow assay formats, or other suitable applications.

[0102] The components of the device 20 comprise relatively inexpensive materials, such as paper and plastic materials, which may be assembled with relative ease. This may allow different fluidic devices to be fabricated in a high through-put modular format. This may also allow the device 20 to be seamlessly integrated into existing lateral flow and vertical flow assay formats as suggestedin FIGS. 7-9. Thus, with a modest change in fabrication of existing LFAs and VFAs, greater flexibility and control may be achieved.

[0103] In some embodiments, the source pad 22 and the drain pad 24 may comprise a cellulosic material, such as paper, cardboard, gas fiber, filter paper etc. In some embodiments, the source pad 22 and the drain pad 24 may be glass fiber conjugate pads, filter paper pads, etc. The porous material of the source pad 22 and the drain pad 24 includes a number of small intersecting capillaries that help in the passive transport of fluid through capillary action when dry.

[0104] Once saturated, however, the fluid is trapped within the sorbent pad 22, 24 and held fast through capillary pressure at the liquid-air interface of each of the individual pores at the interface. Excess pressure that exceeds the summated capillary burst pressure of each of these individual capillaries needs to be applied for the fluid to move past from the discrete sorbent pad 22 into the air gap 28.

[0105] In some embodiments, the bottom inlet strip 30, the top outlet strip 32, and the bottom outlet strip 36 of the flow controller 26 may comprise a plastic material, for example, such as a polyethylene, a polypropylene, a polycarbonate, a polyvinyl chloride, or any combination thereof. In certain embodiments, at least one of the bottom inlet strip 30, the top outlet strip 32, and the bottom outlet strip 36 comprise a hydrophobic plastic material. The hydrophobic plastic material of the bottom inlet strip 30, the top outlet strip 32, and / or the bottom outlet strip 36 may be, for example, double-sided acrylic-based adhesive tape in some embodiments. In other embodiments, the plastic material of the bottom inlet strip 30, top outlet strip 32, and the bottom outlet strip 36 may comprise, for example, a material selected from the group consisting of polyethylene terephthalate (PET), acrylic, polycarbonate, polydimethylsiloxane (PDMS), water resistant cardboard / glass, thick paper stock material, and any combination thereof.

[0106] The base strip 21 and the connecting strip 34 of the flow controller 26 may comprise a plastic material, such as any plastic material disclosed herein. In some embodiments, the plastic material of the base strip 21 and the connecting strip 34 may be different from the plastic material of the bottom inletstrip 30, top outlet strip 32, and the bottom outlet strip 36. In some embodiments, the plastic material of the connecting strip 34 may be different from the plastic material of the base strip 21 .

[0107] In an illustrative embodiment, the plastic material of the connecting strip 34 and the base strip 21 is hydrophilic. The hydrophilic plastic material of the connecting strip 34 and the base strip 21 may be Mylar® or a stretched polyester film of biaxially-oriented polyethylene terephthalate (BoPET) in some embodiments. In some embodiments, the plastic material of the connecting strip 34 or the base strip 21 may comprise, for example, a material selected from the group consisting of polyethylene terephthalate (PET), acrylic, polycarbonate, polydimethylsiloxane (PDMS), water resistant cardboard / glass, thick paper stock material, and any combination thereof.

[0108] However, the flow surface 34S of the connecting strip 34 may be hydrophilic, hydrophobic, or a combination thereof. In some embodiments, the flow surface 34S of the connecting strip 34 may be a plasma treated surface or a UV-ozone treated surface, which causes the flow surface 34S of the connecting strip 34 to be hydrophilic. Similarly, the flow surface 21 S of the base strip 21 may be hydrophilic, hydrophobic, or a combination thereof like the flow surface 34S of the connecting strip 34 in some embodiments.

[0109] In other embodiments, the flow controller may include a protrusion 340 as shown in the embodiment of FIGS. 5A-C on the flow surface 34S of the connecting strip 34. The protrusion 340 may be hydrophilic, hydrophobic, or a combination thereof. For example, the protrusion 340 may be formed by printing a hydrophobic ink, adding a chemical attachment of molecules, and / or micro / nanostructuring the flow surface 34S. Protrusions 340 will be discussed in greater detail with respect to FIGS. 5A and 5B.

[0110] T urning again to the fluidic device 20, the device 20 includes the source pad 22, the drain pad 24, and the flow controller 26 as shown in FIGS. 1- 2. The flow controller 26 includes the bottom inlet strip 30, the top outlet strip 32, the bottom outlet strip 36, the base strip 21 , and the connecting strip 34 as shown in FIGS. 1 and 2. The source pad 22 and the drain pad 24 are coupled to the base strip 21 in spaced apart relation to define the gap 28 therebetween. Thebase strip 21 is spaced apart from the connecting strip 34 to define the gap 28 therebetween. Therefore, the gap 28 is defined between the source pad 22, the drain pad 24, the base strip 21 , and the connecting strip 34 as shown in FIGS. 1- 1C. In an illustrative embodiment, the air gap 28 between the source pad 22 and the drain pad 24 is open on either side of the air gap 28.

[0111] The bottom inlet strip 30 and the bottom outlet strip 36 are both coupled to the surface 21 S of the base strip 21 as shown in FIG. 1 . The bottom inlet strip 30 is coupled to one end of the base strip 21 so that the bottom inlet strip 30 is located between the source pad 22 and the base strip 21 as shown in FIG. 1. Similarly, the bottom outlet strip 36 is coupled to an opposite end of the base strip 21 so that the bottom outlet strip 36 is located between the drain pad 24 and the base strip 21 as shown in FIG. 1 .

[0112] The top outlet strip 32 is coupled to the top surface 24TS of the drain pad 24 so that the top outlet strip 32 is located between the drain pad 24 and the connecting strip 34 as shown in FIG. 1 . The top outlet strip 32 extends partway into the gap 28, while the bottom outlet strip 32 is flush with the drain pad 24 as shown in FIG. 1 .

[0113] The bottom inlet strip 30 temporarily pins the fluid at the source pad 22 until a critical pressure is reached. Once critical pressure at the fluid front is reached, surface directed capillary flows along the flow surfaces 34S, 21 S pull the liquid through the air gap region 28 and into the drain pad 24. The top and bottom outlet strips 32, 36 cooperate to prevent the fluid applied to or in the drain pad 24 from flowing opposite the lateral direction L back towards the source pad 22 as the flow of the fluid flows along surfaces 34S, 21 S through the air gap 28 to the drain pad 24.

[0114] The source pad 22 is shaped to include a top surface 22TS, the bottom surface 22BS, and outer edges 22E1 , 22E2, 22E3, 22E4 that extend between and interconnect the top and bottom surfaces 22TS, 22BS to define an outer perimeter of the source pad 22 as shown in FIGS. 1 and 2. The lateral outer edges 22E3, 22E4 extend laterally, while the longitudinal outer edges 22E1 , 22E2 extend longitudinally between and interconnect the lateral outer edges 22E3, 22E4.

[0115] The outer edge 22E1 faces the gap 28 as shown in FIG. 1 . The second end 34I of the connecting strip 34 extends past the outer edge 22E1 of the source pad 22, but ends before the outer edge 22E2 so as to extend over only a portion of the source pad 22. The second end 34I of the connecting strip 34 is spaced apart from the top surface 22TS of the source pad 22 to define an inlet air gap G therebetween as shown in FIG. 1 .

[0116] The drain pad 24 is shaped to include the top surface 24TS, the bottom surface 24BS, and outer edges 24E1 , 24E2, 24E3, 24E4 that extend between and interconnect the top and bottom surfaces 24TS, 24BS to define an outer perimeter of the drain pad 24 as shown in FIGS. 1 and 2. The lateral outer edges 24E3, 24E4 extend laterally, while the longitudinal outer edges 24E1 , 24E2 extend longitudinally between and interconnect the lateral outer edges 24E3, 24E4. The outer edge 24E2 faces the gap 28 as shown in FIG. 1.

[0117] The top outlet strip 32 extends past the outer edge 24E2 of the drain pad 24 as shown in FIG. 1 . The bottom outlet strip 36 is flush with the outer edge 24E2 of the drain pad 24 as shown in FIG. 1. The top outlet strip 32 is also spaced apart from the outer lateral outer edge 24E2.

[0118] The base strip 21 defines a surface 21 S that faces the flow surface 34S of the connecting strip 34 as shown in FIGS. 1-1C. The gap 28 is defined between the source pad 22, the drain pad 24, the connecting strip 34, the base21 as shown in FIGS. 1-1C. In some embodiments, the base strip 21 is a base member 21 that defines the surface 21 S. In some embodiments, the source pad22 and the drain pad 24 may be coupled to a suitable object or member, like the housing of a test device, which will define the surface 21 S.

[0119] A method of using the fluidic device 20 may include several steps as shown in FIGS. 1 A-C. First, an amount of a first fluid F may be applied to the source pad 22 as shown in FIG. 1A. Depending on the amount of fluid added, the fluid may be temporarily pinned at the source pad 22 until the capillary burst pressure or critical pressure at the fluid front is reached as suggested in FIG. 1 B. More fluid may be applied to cause a pressure within the source pad 22 to exceed the capillary burst pressure or critical pressure to drive a portion of the amount of the first fluid F from the source pad 22 to the first end 34I of theconnecting strip 34 of the flow controller 26 as shown in FIGS. 1 A-C. In some embodiments, an amount of a buffer solution may be applied to the source pad 22 and the drain pad 24 before applying the amount of the first fluid F.

[0120] Once the critical pressure is reached, the method includes transporting the first fluid F in the lateral direction L along the flow surface 21 of the base strip 21 and the flow surface 34 of the connecting strip 34 of the flow controller 26 from the source pad 22 to the drain pad 24 across the gap 28 to saturate the drain pad 24 with the first fluid F. The method further includes preventing the first fluid F from flowing opposite the lateral direction L back towards the source pad 22 so that the first fluid F only flows in the lateral direction L from the source pad 22 to the drain pad 24. As the fluid flows into or is applied to the drain pad 24, the capillary burst valve provided by the top and bottom outlet strips 32, 36 prevents the fluid in the drain pad 24 from flowing opposite the lateral direction back toward the source pad 22.

[0121] A method of assembling the fluidic device 20 includes several steps. The method includes arranging the drain or second sorbent pad 24 in spaced apart relation from the source or first sorbent pad 22 to form the gap 28 therebetween. The method further includes coupling the bottom inlet strip 30 of the flow controller 26 to the bottom surface 22BS of the source pad 22, coupling the top outlet strip 32 of the flow controller 26 to the top surface 24TS of the drain pad 24, and coupling the bottom outlet strip 36 of the flow controller 26 to the bottom surface 24BS of the drain pad 24.

[0122] In some embodiments, the top outlet strip 32 is coupled to the top surface 24TS of the drain pad 24 so that a portion of the top outlet strip 32 extends partway into the gap 28 or is offset from the outer edge 24E2 of the drain pad 24. In some embodiments, the top and bottom outlet strips 32, 36 are each coupled to the respective surfaces 24TS, 24BS of the drain pad 24 so that top and bottom outlet strips 32, 36 are flush with the outer edge 24E2 of the drain pad 24.

[0123] The method further includes coupling the first end 340 of the connecting strip 34 of the flow controller 26 to the top outlet strip 32 of the flow controller 26 on the drain pad 24 so that the second end 34I of the connectingstrip 34 of the flow controller 26 extends over a portion of the top surface 22TS of the source pad 22 to bridge the gap 28 between the source pad 22 and the drain pad 24. In some embodiments, the method further includes coupling a top inlet strip to the source pad 22 and coupling the second end 341 of the connecting strip 34 to the top inlet strip to bridge the gap 28 between the source pad 22 and the drain pad 24 on a top side of the gap 28.

[0124] The method further includes coupling the first end 210 of the base strip 21 of the flow controller 26 to the bottom outlet strip 36 of the flow controller 26 on the drain pad 24 and coupling the second end 211 of the base strip 21 of the flow controller 26 to the bottom inlet strip 30 on the source pad 22 so that the base strip 21 of the flow controller 26 bridges the gap 28 between the source pad 22 and the drain pad 24 on a bottom side of the gap 28.

[0125] In some embodiments, the method may include coupling the different strips in a different order. In some embodiments, the bottom inlet and outlet strips 30, 36 may be coupled to the base strip 21 first and the source and drain pads 22, 24 coupled to the respective bottom inlet and outlet strips 30, 36 on the base strip 21 to put the source pad 22 and the drain pad 24 in spaced apart relation to form the gap 28 therebetween. The top outlet strip 32 and the top inlet strip may be coupled to the respective source and drain pads 22, 24 when the source pad 22 and the drain pad 24 already assembled on the base strip 21.

[0126] The connecting strip 34 may then be coupled to the top outlet strip 32 so that the second end 34I of the connecting strip 34 of the flow controller 26 extends over a portion of the top surface 22TS of the source pad 22 to bridge the gap 28. In some embodiments, the respective ends 34I, 340 may be coupled to the top outlet strip 32 and the top inlet strip.

[0127] Another embodiment of a fluidic device 220 in accordance with the present disclosure is shown in FIG. 4. The fluidic device 220 is substantially similar to the fluidic device 20 shown in FIGS. 1-2 and described herein.Accordingly, similar reference numbers in the 200 series indicate features that are common between the fluidic device 20 and the fluidic device 220. The description of the fluidic device 20 is incorporated by reference to apply to thefluidic device 220, except in instances when it conflicts with the specific description and the drawings of the fluidic device 220.

[0128] The fluidic device 220 includes a source pad 222, a drain pad 224, and a flow controller 226 as shown in FIG. 4. The flow controller 226 includes a base strip 221 , a bottom inlet strip 230, a top outlet strip 232, a connecting strip 234, a bottom outlet strip 236, and a top inlet strip 238 as shown in FIG. 4.

[0129] The source pad 222 and the drain pad 224 are coupled to the base strip 221 in spaced apart relation to define the gap 228 therebetween as shown in FIG. 4. The base strip 221 is spaced apart from the connecting strip 234 to define the gap 228 therebetween. Therefore, the gap 228 is defined between the source pad 222, the drain pad 224, the base strip 221 , and the connecting strip 234 as shown in FIG. 4.

[0130] The bottom inlet strip 230 is coupled to a bottom surface 222BS of the source pad 222 and a flow surface 221 S of the base strip 221 at one end of the base strip 221 so that the bottom inlet strip 230 is located between the source pad 222 and the base strip 221 as shown in FIG. 4. The top outlet strip 232 is coupled to a top surface 224TS of the drain pad 224 so that the top outlet strip 232 is located between the drain pad 224 and the connecting strip 234. The bottom outlet strip 236 is coupled to a bottom surface 224BS of the drain pad 224 and the flow surface 221 S of the base strip 221 at the other end of the base strip 221 so that the bottom outlet strip 236 is located between the drain pad 224 and the base strip 221 as shown in FIG. 4.

[0131] Both the base strip 221 and the connecting strip 234 extend between the source pad 222 and the drain pad 224 on top and bottom sides of the source pad 222 and the drain pad 224 to bridge the air gap 228 therebetween as shown in FIG. 4. The base strip 221 extends from a first or outlet end 2210 coupled to the bottom outlet strip 236 on the drain pad 224 to a second or inlet end 2211 coupled to the bottom inlet strip 230 on the source pad 222 to bridge the air gap 228 between the source pad 222 and the drain pad 224 on a bottom side of the air gap 228 as shown in FIG. 4. The connecting strip 234 extends from a first end 2340 coupled to the top outlet strip 232 on the drain pad 224 to a second end 234I that extends over the source pad 222 to bridge thegap 228 between the source pad 222 and the drain pad 224 on a top side of the air gap 228 as shown in FIG. 4.

[0132] Unlike the embodiment of FIG. 1 , in which the second end 34I of the connecting strip 34 overhangs the source pad 22 such that the connecting strip 34 is vertically spaced apart from the source pad 22, the connecting strip 234 is directly coupled to the source pad 222. The top inlet strip 238 extends between and interconnects the connecting strip 234 and the source pad 222 near the second end 2340 of the connecting strip 234 as shown in FIG. 4.

[0133] The top inlet strip 238 extends between and interconnects the connecting strip 234 and the source pad 222 at a location between the second end 2340 and the first end 2340 of the connecting strip 234 as shown in FIG. 4. The top inlet strip 238 does not block the flow of fluid into the gap 228. The fluid still flows in the lateral direction L along the flow surface 221 S of the base strip 221 and the flow surface 234S of the connecting strip 234 that face the gap 228 when the fluid is applied to the source pad 222.

[0134] The top outlet strip 232 and cooperates with the bottom outlet strip 236 to prevent the fluid from flowing opposite the lateral direction L back towards the source pad 222. The top outlet strip 232 and the bottom outlet strip 236 thereby provide a burst valve that prevents the fluid from flowing opposite to the desired direction L so that the device 220 may be integrated into existing lateral flow assay formats, vertical flow assay formats, or other suitable applications.

[0135] The top outlet strip 232 extends partway into the gap 228 between the source pad 222 and the drain pad 224 as shown in FIG. 4. The bottom outlet strip 236 is flush with the drain pad 224 as shown in FIG. 4.

[0136] Another embodiment of a fluidic device 320 in accordance with the present disclosure is shown in FIGS. 5A-C. The fluidic device 320 is substantially similar to the fluidic device 20 shown in Figs. 1-2 and described herein.Accordingly, similar reference numbers in the 300 series indicate features that are common between the fluidic device 20 and the fluidic device 320. The description of the fluidic device 20 is incorporated by reference to apply to the fluidic device 320, except in instances when it conflicts with the specific description and the drawings of the fluidic device 320.

[0137] The fluidic device 320 includes a source pad 322, a drain pad 324, and a flow controller 326 as shown in FIGS. 5A-C. The flow controller 326 includes a base strip 321 , an inlet strip 330, a top outlet strip 332, a connecting strip 334, a bottom outlet strip 336, and a plurality of protrusions 340 as shown in FIGS. 5A-C.

[0138] The source pad 322 and the drain pad 324 are coupled to the base strip 321 in spaced apart relation to define the gap 328 therebetween as shown in FIGS. 5A-C. The base strip 321 is spaced apart from the connecting strip 334 to define the gap 328 therebetween. Therefore, the gap 328 is defined between the source pad 322, the drain pad 324, the base strip 321 , and the connecting strip 334 as shown in FIGS. 5A-C.

[0139] The bottom inlet strip 330 is coupled to a bottom surface 322BS of the source pad 322, the top outlet strip 332 is coupled to a top surface 324TS of the drain pad 324, and the bottom outlet strip 336 is coupled to a bottom surface 324BS of the drain pad 324 as shown in FIGS. 5A and 5B. Both the base strip 321 and the connecting strip 334 extend between the source pad 322 and the drain pad 324 on top and bottom sides of the source pad 322 and the drain pad 324 to bridge the air gap 328 therebetween as shown in FIGS. 5A and 5B.

[0140] The base strip 321 extends from a first or outlet end 3210 coupled to the bottom outlet strip 336 on the drain pad 324 to a second or inlet end 3211 coupled to the bottom inlet strip 330 on the source pad 322 to bridge the air gap 328 between the source pad 322 and the drain pad 324 on a bottom side of the air gap 328 as shown in FIGS. 5A and 5B. The connecting strip 334 extends from a first end 3340 coupled to the top outlet strip 332 on the drain pad 324 to a second end 334I that extends over the source pad 322 to bridge the gap 328 between the source pad 322 and the drain pad 324 on a top side of the air gap 328 as shown in FIGS. 5A and 5B.

[0141] Each protrusion 340 extends from the flow surface 334S of the connecting strip 334 into the gap 328 between the source pad 322 and the drain pad 324. The protrusions 340 extend perpendicular to the flow of the fluid and are configured to slow the flow of the fluid from the source pad 322 to the drain pad 324. In some embodiments, the protrusions 340 may extend from the flowsurface 321 S of the base strip 321 into the gap 328 between the source pad 322 and the drain pad 324.

[0142] As the fluid enters the gap 328, the fluid transitions from a capillary driven flow in the sorbent source pad 322 to a surface directed flow within the parallel strips of plastic strips 321 , 334 sandwiching the sorbent pad 322. Flow resistance of various degrees may be incorporated using the protrusions 340 or “speed-bumps” within the surface directed flow channel between the connecting strip 334 and the base strip 321 .

[0143] These protrusions 340 may be, for example, printed hydrophobic lines on the flow surface 334S of the connecting strip 334 perpendicular to the direction L of fluid flow. Controlling the thickness and the hydrophobicity of the protrusions 340 determines the excess pressure required within the advancing fluid front to surmount the protrusions 340 and move on.

[0144] The protrusions 340 are spaced apart from each other along the connecting strip 334 in the lateral direction L as shown in FIGS. 5A-C. The number of protrusions 340 as well as the distance 340D between adjacent protrusions 340 may be varied based on the desired time delay of the flow of the fluid across the gap 328 from the source pad 322 to the drain pad 324.

[0145] For example, the protrusions 340 may be spaced apart from each other a predetermined distance so as to control the time delay of the flow of the fluid from the source pad 322 to the drain pad 324. Additionally, the height 340H and / or thickness 340T of each protrusion 340 may be varied to predetermined dimensions to control the time delay of the flow of the fluid from the source pad 322 to the drain pad 324.

[0146] Every time the fluid front contacts one of the protrusions 340, the fluid gets pinned at these contact points until the curvature of the fluid front undergoes the change (corresponding to exceeding the burst valve threshold), which essentially slows down the advancing fluid front within the air gap regions. The thickness 340T and / or height 340H of the protrusions 340 as well as the number of protrusions 340 along the path of the fluid front determines the time delay. The length of the surface directed flow segment in addition to the surface energy of the film within the connecting strip 334 may determine the flowresistance and may be used as an alternative means to print the protrusions 340.

[0147] Another embodiment of a fluidic device 420 in accordance with the present disclosure is shown in FIGS. 6A-C. The fluidic device 420 is substantially similar to the fluidic device 20 shown in Figs. 1-2 and described herein.Accordingly, similar reference numbers in the 400 series indicate features that are common between the fluidic device 20 and the fluidic device 420. The description of the fluidic device 20 is incorporated by reference to apply to the fluidic device 420, except in instances when it conflicts with the specific description and the drawings of the fluidic device 420.

[0148] The fluidic device 420 includes cascaded diode valves each including a source pad, a drain pad, which becomes the source pad for the adjacent pad, and a flow controller, that controls the flow of fluid in the lateral direction L from each valve as shown in FIGS. 6A-C. The fluidic device 420 includes a plurality of sorbent pads 422, 424, 442, 444, 446 and flow controllers 426, 448, 450, 452 that control the flow of fluid in the lateral direction L between each of the respective pads 422, 424, 442, 444, 446.

[0149] In an illustrative embodiment, the fluidic device 420 includes more than three sorbent pads 422, 424, 422, 444, 446, e.g. two cascaded diode valves. In an illustrative embodiment, the fluidic device 420 includes more than four sorbent pads 422, 424, 422, 444, 446, e.g. three cascaded diode valves. In an illustrative embodiment, the fluidic device 420 includes five sorbent pads 422, 424, 422, 444, 446, e.g. four cascaded diode valves.

[0150] In other embodiments, the fluidic device 420 includes more than five sorbent pads 422, 424, 442, 444, 446. The fluidic device 420 may include as many cascaded diode valves as needed.

[0151] The second sorbent pad 424 is located in spaced apart relation from the first sorbent pad 422 to form a first gap 428 therebetween as shown in FIGS. 6A and 6B. The first flow controller 426 is configured to control the flow of the fluid in the lateral direction L from the first sorbent pad 422 to the second sorbent pad 424 across the first gap 428.

[0152] The third sorbent pad 442 is located in spaced apart relation from the second sorbent pad 424 to form a second gap 454 therebetween as shown in FIGS. 6A and 6B. The second flow controller 448 is configured to control the flow of the fluid in the lateral direction L from the second sorbent pad 424 to the third sorbent pad 442 across the second gap 454 therebetween.

[0153] The fourth sorbent pad 444 is located in spaced apart relation from the third sorbent pad 442 to form a third gap 456 therebetween as shown in FIGS. 6A and 6B. The third flow controller 450 is configured to control the flow of the fluid in the lateral direction L from the third sorbent pad 442 to the fourth sorbent pad 444 across the third gap 456 therebetween,

[0154] The fifth sorbent pad 446 is located in spaced apart relation from the fourth sorbent pad 442 to form a fourth gap 458 therebetween as shown in FIGS. 6A and 6B. The fourth flow controller 452 is configured to control the flow of the fluid in the lateral direction L from the fourth sorbent pad 444 to the fifth sorbent pad 446 across the fourth gap 458 therebetween,

[0155] Each flow controller 426, 448, 450, 452 includes the bottom inlet strip 430, 460, 470, 480, a top outlet strip 432, 462, 472, 482, and a connecting strip 434, 464, 474, 484 as shown in FIGS. 6A-C. Each bottom inlet strip 430, 460, 470, 480 is coupled to the bottom surface of the respective sorbent pad 422, 424, 442, 444 to form the bottom outlet strip that cooperates with the top outlet strip 432, 462, 472, 482 to prevent the fluid from flowing opposite to the desired direction L. The last sorbent pad 446 has a bottom outlet strip 486 coupled to a bottom surface thereof. Each top outlet strip 432, 462, 472, 482 is coupled to a top surface of the respective sorbent pad 424, 442, 444, 446.

[0156] The flow controllers 426, 448, 450, 452 share a single base strip 421 as shown in FIGS. 6A-C. The base strip 421 extends between the sorbent pads 422, 424, 442, 444, 446 as shown in FIGS. 6A-C. Each of the sorbent pads 422, 424, 442, 444, 446 may be coupled to the base strip 421 as shown in FIGS. 6A-C. Each of the sorbent pads 422, 424, 442, 444, 446 may be spaced apart laterally along the base strip 421 as shown in FIGS. 6A-C.

[0157] Each connecting strip 434, 464, 474, 484 extends from a first end coupled to the respective top outlet strip 432, 462, 472, 482 to a second end thatextends over a portion of the preceding sorbent pad 422, 424, 442, 444 to bridge the respective gap 428, 454, 456, 458 between the associated sorbent pads 422, 424, 442, 444, 446. The top outlet strip 432, 462, 472, 482 and the strip 460, 470, 480, 486 coupled to the bottom surface of the respective sorbent pad 422, 424, 442, 444, 446 cooperate to prevent the fluid from flowing opposite the lateral direction L back towards the preceding sorbent pad 422, 424, 442, 444. In an illustrative embodiment, the top outlet strip 432, 462, 472, 482 extends partway into the respective gap 428, 454, 456, 458 between the associated sorbent pads 422, 424, 442, 444, 446.

[0158] The first flow controller 426 includes the base strip 421 , the bottom inlet strip 430, the top outlet strip 432, and the connecting strip 434 as shown in FIGS. 6A-C. The bottom inlet strip 430 is coupled to the bottom surface of the first sorbent pad 422. The top outlet strip 432 is coupled to a top surface of the second sorbent pad 424. The bottom inlet strip 460 coupled to the sorbent pad 424 provides the bottom outlet strip 460 of the first flow controller 426. The bottom inlet strip 430 and the bottom outlet strip 460 are coupled to the flow surface 421 S of the base strip 421. The connecting strip 434 extends from a first end 4340 coupled to the respective top outlet strip 432 on the second sorbent pad 424 to a second end 434I that extends over a portion of the first sorbent pad 422 to bridge the respective gap 428. The top outlet strip 432 extends partway into the first gap 428 so that the outer end 432E is located in the first gap 428 as shown in FIG. 6C.

[0159] The second flow controller 448 includes the base strip 421 , the bottom inlet strip 460, the top outlet strip 462, and the connecting strip 464 as shown in FIGS. 6A-C. The bottom inlet strip 460 is coupled to the bottom surface of the second sorbent pad 422. The top outlet strip 462 is coupled to a top surface of the third sorbent pad 442. The bottom inlet strip 470 coupled to the sorbent pad 442 provides the bottom outlet strip 470 of the second flow controller 448. The bottom inlet strip 460 and the bottom outlet strip 470 are coupled to the flow surface 421 S of the base strip 421 . The connecting strip 464 extends from a first end 464A coupled to the respective top outlet strip 462 on the fourth sorbent pad 444 to a second end 464B that extends over a portion ofthe second sorbent pad 424 to bridge the respective gap 454. The top outlet strip 462 extends partway into the second gap 454 so that the outer end 462E is located in the second gap 454 as shown in FIG. 6C.

[0160] The third flow controller 450 includes the base strip 421 , the bottom inlet strip 470, the top outlet strip 472, and the connecting strip 474 as shown in FIGS. 6A-C. The bottom inlet strip 470 is coupled to the bottom surface of the third sorbent pad 442. The top outlet strip 472 is coupled to a top surface of the fourth sorbent pad 444. The bottom inlet strip 480 coupled to the sorbent pad 444 provides the bottom outlet strip 480 of the third flow controller 450. The bottom inlet strip 470 and the bottom outlet strip 480 are coupled to the flow surface 421 S of the base strip 421. The connecting strip 474 extends from a first end 474A coupled to the respective top outlet strip 472 on the fifth sorbent pad 446 to a second end 474B that extends over a portion of the third sorbent pad 442 to bridge the respective gap 456. The top outlet strip 472 extends partway into the third gap 456 so that the outer end 472E is located in the third gap 456 as shown in FIG. 6C.

[0161] The fourth flow controller 452 includes the bottom inlet strip 480, the top outlet strip 482, a bottom outlet strip 486, and the connecting strip 484 as shown in FIGS. 6A-C. The bottom inlet strip 480 is coupled to the bottom surface of the fourth sorbent pad 444. The top outlet strip 482 is coupled to a top surface of the fifth sorbent pad 446. The bottom outlet strip 486 is coupled to a bottom surface of the fifth sorbent pad 446. The bottom inlet strip 480 and the bottom outlet strip 486 are coupled to the flow surface 421 S of the base strip 421 . The connecting strip 484 extends from a first end 484A coupled to the respective top outlet strip 482 on the fifth sorbent pad 446 to a second end 484B that extends over a portion of the fourth sorbent pad 444 to bridge the respective gap 458. The top outlet strip 482 extends partway into the fourth gap 458 so that the outer end 482E is located in the fourth gap 458 as shown in FIG. 6C.

[0162] As shown in FIG. 7, the fluidic device 420 may be integrated into a lateral flow assay 425 to provide a lateral flow device 427. In an illustrative embodiment, a lateral flow device sheet 423 may include a cascaded device 420integrated with lateral flow assays 425. The sheet 423 may be segmented into individual strips of lateral flow devices 427 as show in FIG. 7.

[0163] The fluidic device 420 may also be integrated into other lateral flow assays 435, 445 as shown in FIGS. 8 and 9. FIG. 8 shows another lateral flow device 437 integrated with the cascaded device 420 with an extension section 439 of the drain pad configured to link the cascaded device 420 with the lateral flow assay 435. FIG. 9 shows another lateral flow device 447 similar to the lateral flow device 437 of FIG. 8, but the paper bridge 449 connects an adjacent lateral flow assay 445.

[0164] Another embodiment of a fluidic device 520 in accordance with the present disclosure is shown in FIGS. 10A-D. The fluidic device 520 is substantially similar to the fluidic device 20, 420 shown in Figs. 1-2 and 7A-C and described herein. Accordingly, similar reference numbers in the 500 series indicate features that are common between the fluidic device 20, 420 and the fluidic device 520. The description of the fluidic device 20, 420 is incorporated by reference to apply to the fluidic device 520, except in instances when it conflicts with the specific description and the drawings of the fluidic device 520.

[0165] The fluidic device 520 includes cascaded diode valves similar to the embodiment of FIGS. 6A-C. However, the cascaded diode valves is integrated into a vertical flow assay format. The fluidic device 520 includes a modified diode valve section in the series of cascaded diode valves as shown in FIGS. 10A-D.

[0166] The fluidic device 520 includes the cascaded diode valves along with the modified section as shown in FIGS. 10A-D. However, the cascaded diode valves is integrated into a vertical flow assay format.

[0167] The fluidic device 520 includes a modified diode valve section in the series of cascaded diode valves as shown in FIGS. 10A-D. The modified section of the fluidic device 520 includes a first sorbent pad 522, a second sorbent pad 524, and a flow controller 526 as shown in FIGS. 10A-D.

[0168] The first sorbent pad 522 is made of a porous paper material like in the other embodiments. However, the second sorbent pad 524 may be made of a non-porous paper material.

[0169] The flow controller 526 controls the flow of the fluid in the lateral direction L into the gap 528. The flow controller 526 includes a base strip 521 , a bottom inlet strip 530, a top outlet strip 532, a bottom outlet strip 536, a connecting strip 534, and a membrane member 529 as shown in FIGS. 10A-D.

[0170] The cascaded diode valves share a single base strip 521 as shown in FIGS. 10A-D. The base strip 521 has a base pad 521 B and support strips 523, 525 as shown in FIGS. 10A-D. The support strips 523, 525 are each coupled to a top surface 521 S of the base pad 521 B.

[0171] The cascaded diode valves are coupled to a top surface 523S, 525S of the respective support strips 523, 525 as shown in FIGS. 10A-D. The support strips 532, 525 define the flow surface 523S, 525S for the other cascaded diode valves. The first sorbent pad 522 and the second sorbent pad 524 are coupled to respective support strips 523, 525 so that the second sorbent pad 524 is spaced apart from the first sorbent pad 522 to define the gap 528 therebetween as shown in FIGS. 10A-D.

[0172] The bottom inlet strip 530 is coupled to the bottom surface 522BS of the first sorbent pad 522 so that the bottom inlet strip 530 is located vertically between the first sorbent pad 522 and the first support strip 523. The top outlet strip 532 is coupled to the top surface 524TS of the second sorbent pad 524 so that the top outlet strip 532 is located vertically between the second sorbent pad 524 and the second support strip 525. The connecting strip 526 extends from a first end 5340 coupled to the top outlet strip 532 to a second end 534I that extends over a portion of the top surface 522TS of the first sorbent pad 522 to bridge the gap 528. The membrane member 529 is coupled to the base pad 521 B of the base strip 521 in the gap 528 so that the membrane member 529 is located between the first and second sorbent pads 522, 524.

[0173] The first support strip 523 and the bottom inlet strip 530 extend partway into the gap 528 between the first sorbent pad 522 and the second sorbent pad 524 as shown in FIGS. 10A-D. In other words, the bottom inlet strip 530 extends past an outer end 522E1 of the first sorbent pad 522 into the gap 528. The bottom inlet strip 530 confronts the membrane member 529 in the gap 528.

[0174] As fluid saturates the first sorbent pad 522, the bottom inlet strip 530 pins the flow of the fluid at the outer edge 530E of the bottom inlet strip 530. The abrupt, step like change in the dimension of the gap 528 causes part of the fluid front to be pinned at the bottom inlet strip 530. The connecting strip 534 allows the fluid to continue to flow in the lateral direction L across the flow surface 534S until the fluid front reaches the top outlet strip 532 as shown in FIG. 10B.

[0175] Excess fluid pressure causes the amount of fluid in the gap 528 to increase / expand until the fluid F contacts the membrane member 529. In other words, the fluid flows in the vertical direction V from the flow surface 534S into the membrane member 529 as shown in FIG. 10B. Thus, the fluidic device 520 provides a vertical flow device. The nitrocellulose membrane member 529 may be adhered to the bottom absorbent pad 521 B. The membrane member 529 may be adhered to the base pad 521 B using a water sol uble / hydrophilic adhesive / glue.

[0176] The membrane member 529 is made of a porous nitrocellulose membrane configured to allow the flow of fluid therethrough. The fluid F is allowed to flow into the membrane 529 so that it may get absorbed into the base strip 521 . The base pad 521 B of the base strip 521 is made of an absorbent material that is configured to absorb some of the fluid.

[0177] Another embodiment of a fluidic device 620 in accordance with the present disclosure is shown in FIGS. 11-11C. The fluidic device 620 is substantially similar to the fluidic device 20 shown in FIGS. 1-2 and described herein. Accordingly, similar reference numbers in the 600 series indicate features that are common between the fluidic device 20 and the fluidic device 620. The description of the fluidic device 20 is incorporated by reference to apply to the fluidic device 620, except in instances when it conflicts with the specific description and the drawings of the fluidic device 620.

[0178] The fluidic device 620 includes a source pad 622, a drain pad 624, and a flow controller 626 as shown in FIGS. 11-11 C. The flow controller 626 includes a base strip 621 , an inlet strip 630, a top outlet strip 632, a bottom outlet strip 636, and a connecting strip 634 as shown in FIGS. 12-12C.

[0179] The source pad 622 and the drain pad 624 are coupled to the base strip 621 in spaced apart relation to define the gap 628 therebetween as shown in FIGS. 11-11 C. The base strip 621 is spaced apart from the connecting strip 634 to define the gap 628 therebetween. Therefore, the gap 628 is defined between the source pad 622, the drain pad 624, the base strip 621 , and the connecting strip 634 as shown in FIGS. 11 -11 C.

[0180] The bottom inlet strip 630 is coupled to a bottom surface 622BS of the source pad 622 so that the bottom inlet strip 630 is located between the source pad 622 and the base strip 621 as shown in FIGS. 11-11C. The top outlet strip 632 is coupled to a top surface 624TS of the drain pad 624. The bottom outlet strip 636 is coupled to a bottom surface 624BS of the drain pad 624 and a top surface of the base strip 621 so that the bottom outlet strip 636 is located between the drain pad 624 and the base strip 621. The base strip 621 extends from the bottom outlet strip 636 on the drain pad 624 to the bottom inlet strip 630 on the source pad 622 to bridge the air gap 628 between the source pad 622 and the drain pad 624 as shown in FIGS. 11 -11 C. The connecting strip 634 extends from a first end 6340 coupled to the top outlet strip 632 on the drain pad 624 to a second end 634I that extends over a top surface 622TS the source pad 622 to bridge the gap 628 between the source pad 622 and the drain pad 624.

[0181] Unlike the embodiment of FIG. 1 , in which the bottom inlet strip 30 is a plastic material, the bottom inlet strip 630 comprises an electrically conductive material and the fluidic device 620 further includes a power source 690 electrically coupled to the bottom inlet strip 630. The power source 690 is configured to change between an off mode and an on mode as shown in FIGS. 11A-C.

[0182] In the off mode, no power is supplied to the bottom inlet strip 630. As a result, the flow of fluid is pinned at the source pad 622 and is prevented from flowing into the gap 628 until the power supply 690 is changed to the on mode. In the on mode, the power supply 690 sends a signal, i.e. a voltage to the bottom inlet strip 630. This causes the flow of fluid to flow into the gap 628 in the lateral direction L across the flow surface 621 S of the base strip 621 and the flow surface 634S of the connecting strip 634 to the drain pad 624 throughelectrowetting. In this way, the timing of the flow of fluid from the source pad 622 to the drain pad 624 may be controlled by switching the power supply 690 from the off mode to the on mode as suggested in FIGS. 11 A-C.

[0183] In an illustrative embodiment, the bottom inlet strip 630 is an electrode. In other embodiments, the bottom inlet strip 630 may be another electrically conductive material.

[0184] Another embodiment of a fluidic device 720 in accordance with the present disclosure is shown in FIG. 12. The fluidic device 720 is substantially similar to the fluidic device 20 shown in FIGS. 1-2 and described herein.Accordingly, similar reference numbers in the 700 series indicate features that are common between the fluidic device 20 and the fluidic device 720. The description of the fluidic device 20 is incorporated by reference to apply to the fluidic device 720, except in instances when it conflicts with the specific description and the drawings of the fluidic device 720.

[0185] The fluidic device 720 includes a center pad 792 and a plurality of diode valves 720A-D as shown in FIG. 12. The center pad 792 is configured to provide passive transportation of a fluid. Each of the valves 720A-D is coupled to the center pad and may have different time delays based on the needs of the device 720.

[0186] The plurality of diode valves 720A-D may include multiple input valves 720A-C and an output valve 720D as shown in FIG. 12. The input valves 720A-C direct fluid to the center pad 792, while the output valve 720D is coupled to the center pad 792 to receive fluid from any one of the input valves 720A-C.

[0187] Each of the valves 720A-D includes a source pad 722A-D, a drain pad 724A-D, and a flow controller 726A-D as shown in FIG. 12. The source pad 722A-D and the drain pad 724A-D of each respective valve 720A-D are located in spaced apart relation to define the gap 728A-D. Each flow controller 726A-D includes a base strip (not shown), a bottom inlet strip 730A-D, a top outlet strip 732A-D, a bottom outlet strip (not shown), and a connecting strip 734A-D as shown in FIG. 12.

[0188] For the input valves 720A-D, the drain pad 724A-C is coupled to the center pad 792, while the source pad 722D output valve 720D is coupled tothe center pad 792 as shown in FIG. 12. Each of the valves 720A-D only allows flow in the lateral direction L. The input valves 720A-C direct the flow of fluid in the lateral direction L to the center pad 792, while the output valve 720D directs the flow of fluid in the lateral direction L from the center pad 792.

[0189] In an illustrative embodiment, the device 720 include three input valves 720A-C and a single outlet valve 720D. In other embodiments, the device 720 may include any number of input valves 720A-C with a single output valve 720D. In other embodiments, the input or the output valves 720A-D may include cascaded diode valves like in FIGS. 6A-C. The last sorbent pad may be coupled to the center pad 792 for the input valves 720A-D, while the first sorbent pad may be coupled to the center pad 792 for the output valve 720D.

[0190] The first diode valve 720A includes a first source pad 722A, a first drain pad 724A, and a first flow controller 726A as shown in FIG. 12. The first drain pad 724A is coupled to the center pad 792 so that the first drain pad 724A is located in spaced apart relation from the first source pad 722A to form a first gap 728A therebetween. The first flow controller 726A is configured to control the flow of fluid from the first source pad 1 2K to the first drain pad 724A across the first gap 728A therebetween.

[0191] The second diode valve 720B includes a second source pad 722B, a second drain pad 724B, and a second flow controller 726B as shown in FIG. 12. The second drain pad 724B is coupled to the center pad 792 so that the second drain pad 724B is located in spaced apart relation from the second source pad 722B to form a second gap 728B therebetween. The second flow controller 726B is configured to control the flow of fluid from the second source pad 722B to the second drain pad 724B across the second gap 728B therebetween.

[0192] The third diode valve 720D includes a third source pad 722D, a third drain pad 724D, and a third flow controller 726D as shown in FIG. 12. The third source pad 722D is coupled to the center pad 792. The third drain pad 724D is located in spaced apart relation from the third source pad 722D to form a third gap 728D therebetween. The third flow controller 726D is configured tocontrol the flow of fluid from the third source pad 722D to the third drain pad 724D across the third gap 728D therebetween.

[0193] The fourth diode valve 720C includes a fourth source pad 722C, a fourth drain pad 724C, and a fourth flow controller 726C as shown in FIG. 12. The fourth drain pad 724C is coupled to the center pad 792 so that the fourth drain pad 724C is located in spaced apart relation from the fourth source pad 722C to form a fourth gap 728C therebetween. The fourth flow controller 726C is configured to control the flow of fluid from the fourth source pad 722C to the fourth drain pad 724C across the fourth gap 728C therebetween.

[0194] Each of the valves 720A-C may have a different time delay. Any of the previous methods, such as protrusions, different materials, timed electrical voltage, etc. as discussed in the other embodiments, may be used to vary the time delay for each valve 720A-C. Additionally, fluid may be applied to each of the source pads 722A-C at different times and / or in different amounts.

[0195] Another embodiment of a fluidic device 820 in accordance with the present disclosure is shown in FIG. 13. The fluidic device 820 is substantially similar to the fluidic device 20, 620 shown in FIGS. 1 -2 and 11-11C and described herein. Accordingly, similar reference numbers in the 800 series indicate features that are common between the fluidic device 20, 620 and the fluidic device 820. The description of the fluidic device 20, 620 is incorporated by reference to apply to the fluidic device 820, except in instances when it conflicts with the specific description and the drawings of the fluidic device 820.

[0196] The fluidic device 820 includes a plurality of source pads 822A-C, a center drain pad 824, and a flow controller 826 as shown in FIG. 13. Each source pad 822A-C is spaced apart from the center drain pad 824 so as to define different respective gaps 828A-C. In an illustrative embodiment, a single flow controller 826 extends between the source pads 822A-C and the drain pad 824. In another embodiment, individual flow controllers 826 may be used for each source pad 822A-C.

[0197] The flow controller 826 includes an inlet strip 830A-C for each source pad 822A-C, a top outlet strip 832, a bottom outlet strip (not shown), and a connecting strip 834 as shown in FIG. 13. Each of the bottom inlet strips 830A-C is made of an electrically conductive material like in the embodiment of FIGS. 11-11C. The bottom inlet strip 830A is coupled to a bottom surface of the source pad 822A, the bottom inlet strip 830B is coupled to a bottom surface of the source pad 822B, and the bottom inlet strip 830C is coupled to a bottom surface of the source pad 822C as shown in FIG. 13. The top outlet strip 832 is coupled to a top surface of the drain pad 824 and extends around the outer perimeter of the drain pad 824 as shown in FIG. 13. The base strip 821 and the connecting strip 834 each extend from the top outlet strip 832 on the drain pad 824 to the source pads 822A-C to bridge the respective gaps 828A-C between the source pads 822A-C and the drain pad 824.

[0198] Another embodiment of a fluidic device 920 in accordance with the present disclosure is shown in FIGS. 14-14C. The fluidic device 920 is substantially similar to the fluidic device 20 shown in FIGS. 1-2 and described herein. Accordingly, similar reference numbers in the 900 series indicate features that are common between the fluidic device 20 and the fluidic device 920. The description of the fluidic device 20 is incorporated by reference to apply to the fluidic device 920, except in instances when it conflicts with the specific description and the drawings of the fluidic device 920.

[0199] The fluidic device 900 includes a source pad 922, a drain pad 924, and a flow controller 926 as shown in FIGS. 14-14C. The flow controller 926 includes a base strip 921 , a bottom inlet strip 930, a top outlet strip 932, a connecting strip 934, a bottom outlet strip 936, and a top inlet strip 938 as shown in FIG. 14.

[0200] The source pad 922 and the drain pad 924 are coupled to the base strip 921 in spaced apart relation to define the gap 928 therebetween as shown in FIGS. 14-14C. The base strip 921 is spaced apart from the connecting strip 934 to define the gap 928 therebetween. Therefore, the gap 928 is defined between the source pad 922, the drain pad 924, the base strip 921 , and the connecting strip 934 as shown in FIGS. 14-14C.

[0201] The bottom inlet strip 930 is coupled to a bottom surface 922BS of the source pad 922 and a flow surface 921 S of the base strip 921 so that the bottom inlet strip 930 is located between the source pad 922 and the base strip921 as shown in FIG. 14. The top inlet strip 938 is coupled to a top surface 922TS of the source pad 922 and extends partway into the gap 928 as shown in FIG. 14.

[0202] The bottom and top inlet strips 930, 938 are arranged so that pinning of the fluid is inverted compared to the embodiment of FIG. 1 . Instead of the fluid being temporarily pinned at the bottom inlet strip 930, the fluid is pinned at the flow surface 934S by the top inlet strip 938 that extends partway into the gap 928 as shown in FIG. 14B.

[0203] The top outlet strip 932 is coupled to a top surface 924TS of the drain pad 924 and extends partway into the gap 928 as shown in FIG. 14. The bottom outlet strip 936 is coupled to a bottom surface 924BS of the drain pad 924 and the flow surface 921 S of the base strip 921 so that the bottom outlet strip 932 is located between the drain pad 924 and the base strip 921 as shown in FIG. 14.

[0204] The base strip 921 extends from the bottom outlet strip 936 on the drain pad 924 to the bottom inlet strip 930 on the source pad 922 to bridge the air gap 928 between the source pad 922 and the drain pad 924 as shown in FIGS. 14-14C. The connecting strip 934 extends from a first end 9340 coupled to the top outlet strip 932 on the drain pad 924 to a second end 934I that extends over the source pad 922 to bridge the gap 928 between the source pad 922 and the drain pad 924 as shown in FIGS. 14-14C. Unlike the embodiment of FIG. 1 , the top inlet strip 938 extends between and interconnects the connecting strip 934 and the source pad 922 near the second end 9340 of the connecting strip 934 as shown in FIGS. 14-140.

[0205] The top and bottom outlet strips 930, 936 cooperate to provide a burst valve that prevents the fluid from flowing opposite the lateral direction L back towards the source pad 922 as shown in FIGS. 14A-C. The top outlet strip 932 extends partway into the gap 928 and cooperates with the bottom outlet strip 936 to prevent the fluid from flowing opposite the lateral direction L back towards the source pad 922 as shown in FIGS. 14A-C. The top outlet strip 932 and the bottom outlet strip 936 thereby provide a burst valve that prevents the fluid from flowing opposite to the desired direction L so that the device 920 may beintegrated into existing lateral flow assay formats, vertical flow assay formats, or other suitable applications.

[0206] Another embodiment of a fluidic device 1020 in accordance with the present disclosure is shown in FIGS. 15-15C. The fluidic device 1020 is substantially similar to the fluidic device 20 shown in FIGS. 1-2 and the fluidic device 920 shown in FIGS. 14-14C and described herein. Accordingly, similar reference numbers in the 1000 series indicate features that are common between the fluidic devices 20, 920 and the fluidic device 1020. The description of the fluidic devices 20, 920 is incorporated by reference to apply to the fluidic device 1020, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1020.

[0207] The fluidic device 1020 includes a source pad 1022, a drain pad 1024, and a flow controller 1026 as shown in FIG. 15. The flow controller 1026 includes a base strip 1021 , a bottom inlet strip 1030, a top outlet strip 1032, a connecting strip 1034, a bottom outlet strip 1036, a top inlet strip 1038, conductive strips 1031 , and magnetic strips 1033 as shown in FIG. 15.

[0208] The base strip 1021 includes a support strip or layer 1023, the conductive strips 1031 , and the magnetic strips 1033 in an illustrative embodiment. The base strip 1021 has layers 1033 of magnetic material, a layer 1023 of plastic material, and the conductive strips 1031 that extend around the layers or strips 1023, 1033 as shown in FIG. 15. The conductive strips 1031 are arranged around the ends of the layers or strips 1023, 1031 so that each conductive strip 1031 sandwiches the support strip 1023 and the magnetic strip 1033 together as shown in FIG. 15.

[0209] The source pad 1022 and the drain pad 1024 are coupled to the conductive strips 1031 on the base strip 1021 in spaced apart relation to define the gap 1028 therebetween as shown in FIGS. 15-15C. The base strip 1021 is spaced apart from the connecting strip 1034 to define the gap 1028 therebetween. Therefore, the gap 1028 is defined between the source pad 1022, the drain pad 1024, the base strip 1021 , and the connecting strip 1034 as shown in FIGS. 15-15C. In an illustrative embodiment, the gap 1028 is defined between the source pad 1022, the drain pad 1024, the conductive strip 1031 on the basestrip 1021 , and the connecting strip 1034 as shown in FIGS. 15-15C. The surface 1031 S of the conductive strip 1031 defines the flow surface 1031 S of the base strip 1021 .

[0210] The bottom inlet strip 1030 is coupled to a bottom surface 1022BS of the source pad 1022 and the conductive strip 1031 that extends around one end of the base strip 1021 so that the bottom inlet strip 1030 is located between the source pad 1022 and the conductive strip 1031 as shown in FIG. 15. The top inlet strip 1038 is coupled to a top surface 1022TS of the source pad 1022 and extends partway into the gap 1028 as shown in FIG. 15.

[0211] The bottom and top inlet strips 1030, 1038 are arranged so that pinning of the fluid is inverted compared to the embodiment of FIG. 1 . Instead of the fluid being temporarily pinned at the bottom inlet strip 1030, the fluid is pinned at the flow surface 1034S by the top inlet strip 1038 that extends partway into the gap 1028 as shown in FIG. 15B.

[0212] The top outlet strip 1032 is coupled to a top surface 1024TS of the drain pad 1024 and extends partway into the gap 1028 as shown in FIG. 15. The bottom outlet strip 1036 is coupled to a bottom surface 1024BS of the drain pad 1024 and the conductive strip 1031 that extends around the opposite end of the base strip 1021 so that the bottom outlet strip 1032 is located between the drain pad 1024 and the conductive strip 1031 as shown in FIG. 15.

[0213] The base strip 1021 extends from one end coupled to the bottom outlet strip 1036 on the drain pad 1024 to another end coupled to the bottom inlet strip 1030 on the source pad 1022 to bridge the air gap 1028 between the source pad 1022 and the drain pad 1024 as shown in FIGS. 15-15C.

[0214] The connecting strip 1034 extends from a first end 10340 coupled to the top outlet strip 1032 on the drain pad 1024 to a second end 10341 that extends over the source pad 1022 to bridge the gap 1028 between the source pad 1022 and the drain pad 1024 as shown in FIG. 15. Unlike the embodiment of FIG. 1 , the top inlet strip 1038 extends between and interconnects the connecting strip 1034 and the source pad 1022 near the second end 10340 of the connecting strip 1034 as shown in FIG. 15.

[0215] The magnetic strips 1033 are coupled to a bottom surface 1021 BS of the base strip 1021 as shown in FIG. 15. One magnetic strip 1033 is coupled to the base strip 1021 at the same end as the source pad 1022, while the other magnetic strip 1033 is coupled to the base strip 1021 at the same end as the drain pad 1024 as shown in FIG. 15. Both conductive strips 1031 extend around the ends of the base strip 1021 and over the magnetic strips 1033 so that each magnetic strip 1033 is located between the bottom surface 1021 BS of the base strip 1021 and the respective conductive strip 1031 .

[0216] The fluidic device 1020 further includes a printed circuit board 1092, contact pads 1094, and a magnet 1096 as shown in FIG. 15. The contact pads 1094 are coupled to the printed circuit board 1092 and the surfaces 1031 S of the conductive strips 1031.

[0217] The narrow gap formed between the source pad 1022 and the conductive strip 1031 facilitate flow of the fluid applied the source pad 1022 freely into the gap 1028 before getting pinned at the top inlet strip 1038. The fluid flows from the source pad 1022 to the drain pad 1024 in the lateral direction L into the gap 1028 through electrowetting. The printed circuit board 1092 sends a signal, i.e. a potential difference across the device 1020. The application of the potential difference between the contact pads 1094 on the printed circuit board 1092 spreads the pinned liquid surface.

[0218] As the contact line expands, the liquid meniscus grows as shown in FIG. 15B. The liquid meniscus grows in height until it comes in contact with the flow surface 1034S. Once contacted, the capillary forces act on the meniscus to pull the meniscus through the gap 1028 and into the drain pad 1024 as shown in FIG. 15C.

[0219] The top and bottom outlet strips 1030, 1036 cooperate to provide a burst valve that prevents the fluid from flowing opposite the lateral direction L back towards the source pad 1022 as shown in FIGS. 15A-C. The top outlet strip 1032 extends partway into the gap 1028 and cooperates with the bottom outlet strip 1036 to prevent the fluid from flowing opposite the lateral direction L back towards the source pad 1022 as shown in FIGS. 15A-C. The top outlet strip 1032 and the bottom outlet strip 1036 thereby provide a burst valve that prevents thefluid from flowing opposite to the desired direction L so that the device 1020 may be integrated into existing lateral flow assay formats, vertical flow assay formats, or other suitable applications.

[0220] Another embodiment of a fluidic device 1120 in accordance with the present disclosure is shown in FIGS. 16A-17D. The fluidic device 1120 is substantially similar to the fluidic device 20 shown in FIGS. 1-2, the fluidic device 920 shown in FIGS. 14-14C, and the fluidic device 1020 shown in FIGS. 15-15C and described herein. Accordingly, similar reference numbers in the 1100 series indicate features that are common between the fluidic devices 20, 920, 1020 and the fluidic device 1120. The description of the devices 20, 920, 1020 is incorporated by reference to apply to the fluidic device 1120, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1120.

[0221] The fluidic device 1120 includes a source pad 1122, a drain pad 1124, and a flow controller 1126 as shown in FIGS. 16A-17D. The flow controller 1126 includes a base strip 1121 , a bottom inlet strip 1130, a top outlet strip 1132, a connecting strip 1134, a bottom outlet strip 1136, a top inlet strip 1138, conductive strips 1131 A, 1131 B, a magnetic strip or layer 1133, and a ledge strip 1141 as shown in FIGS. 16A-17D.

[0222] The base strip 1121 includes a support strip or layer 1123, the conductive strips 1131 A, 1131 B, the magnetic strip 1133, and the ledge strip 1141 in an illustrative embodiment. The base strip 1121 has a layer 1133 of magnetic material, a layer 1123 of plastic material, the conductive layers 1131 A, 1131 B that extend around the layers or strips 1 123, 1133, and the ledge strip 1141 coupled to the support strip 1123 as shown in FIGS. 16A-17D. The magnetic strip 1133 is coupled to a lower surface of the support layer 1023 as shown in FIGS. 16A-17D.

[0223] The conductive strips 1131 A, 1131 B are arranged around the respective ends of the layers or strips 1123, 1131 so that each conductive strip 1131 A, 1131 B sandwiches the support strip 1123 and the magnetic strip 1033 as shown in FIGS. 16A-17D. The ledge strip 1141 is coupled to the support layer1123 in the gap 1128 between the source pad 1122 and the drain pad 1124. The outlet conductive strip 1131 B extends over the ledge strip 1141.

[0224] The source pad 1122 and the drain pad 1124 are coupled to the conductive strips 1131 A, 1131 B on the base strip 1121 in spaced apart relation to define the gap 1128 therebetween as shown in FIGS. 16A-17D. The base strip 1121 is spaced apart from the connecting strip 1134 to define the gap 1128 therebetween. Therefore, the gap 1128 is defined between the source pad 1122, the drain pad 1124, the base strip 1121 , and the connecting strip 1134 as shown in FIGS. 15-150. In an illustrative embodiment, the gap 1128 is defined between the source pad 1122, the drain pad 1124, the support strip 1123 of the base strip 1121 , the conductive strip 1131 B of the base strip 1121 , and the connecting strip 1134 as shown in FIGS. 15-15C. The flow surface 1121 S of the support strip 1123 and the flow surface 1131 S of the conductive strip 1031 together define the flow surface of the base strip 1121 as shown in FIGS. 16A-17D.

[0225] The bottom inlet strip 1130 is coupled to a bottom surface 1122BS of the source pad 1122 and the conductive strip 1131 that extends around one end of the base strip 1121 so that the bottom inlet strip 1130 is located between the source pad 1122 and the conductive strip 1131 as shown in FIGS. 16A-17D. The top inlet strip 1138 is coupled to a top surface 1122TS of the source pad 1122 and extends partway into the gap 1128 as shown in FIGS. 16A-17D.

[0226] The top outlet strip 1132 is coupled to a top surface 1124TS of the drain pad 1124. The bottom outlet strip 1136 is coupled to a bottom surface 1124BS of the drain pad 1124 and the conductive strip 1131 that extends around the opposite end of the base strip 1121 so that the bottom outlet strip 1132 is located between the drain pad 1124 and the conductive strip 1131 B as shown in FIGS. 16A-17D.

[0227] The top outlet strip 1132 and the bottom outlet strip 1136 are flush with an outer edge 1124E of the drain pad 1124 as shown in FIGS. 16A-17D. Instead of extending past the outer edge 1124E2 into the gap 1128 like the other embodiments, the top outlet strip 1132 and the bottom outlet strip 1136 are flush with the outer edge 1124E of the drain pad 1124 to provide the burst valve and prevent backward flow into the gap 1128.

[0228] The base strip 1121 extends from the bottom outlet strip 1136 on the drain pad 1124 to the bottom inlet strip 1130 on the source pad 1122 to bridge the air gap 1128 between the source pad 1122 and the drain pad 1124 on a bottom side of the air gap 1128 as shown in FIGS. 16A-17D. The connecting strip 1134 extends from a first end 11340 coupled to the top outlet strip 1132 on the drain pad 1124 to a second end 1134I coupled to the top inlet strip 1138 on the source pad 1122 to bridge the gap 1128 between the source pad 1122 and the drain pad 1124 on a top side of the air gap 1128 as shown in FIGS. 16A- 17D.

[0229] FIGS. 16A-C show an illustrative electroactive fluidic diode device 1120. The electroactive fluidic diode device 1120 is configured to provide enhanced pinning of the fluid at the source pad 1122 during the OFF state / mode, like as shown in FIG. 16B. Conducting electrodes are included / integrated into the device 1120 to allow for electroactive control of the fluid flow. For this, the forward flow geometry at the inlet (source) of the fluidic diode is configured so as to form a stop valve, i.e. the ledge strip 1141 , that would effectively pin the fluid meniscus when no voltage is applied like as shown in FIG. 16B.

[0230] The fluid de-pins with a rapid response time upon the application of the potential to the electrodes as show in FIG. 16C. To enhance the pinning at the inlet, the conductive film or conductive strip 1131 B is applied over a step or the ledge strip 1141 as shown in FIGS. 16A-C. This way, the geometry at the inlet introduces an abrupt change in geometry for the fluid which more effectively pins the fluid. The pinned fluid may be de-pinned through the application of the potential across the electrodes.

[0231] De-pinning happens due to the electrowetting phenomenon, effectively reducing the contact angle of the fluid meniscus contacting the electrode when a potential is applied and follows the Lippman-Young equation. Application of the potential doesn’t alter the pinned fluid at the drain pad 1124 as the fluid is effectively electrically isolated from the underlying electrodes. The device allows the forward fluid flow within the device 1120 to be electronically gated while still maintaining the single directional flow through the device 1120. FIG. 16A shows the construction of the electroactive fluidic diode device 1120and FIGS. 16B and 16C show the mechanism of the electroactive gating of the fluid flow within the fluidic diode 1120.

[0232] Magnetic tape or the magnetic strip 1133 included / integrated into the device 1120 is configured to facilitate seamless electrical contact with conducting pads 1194 on a printed circuit board (PCB) 1192, either directly or through the use of magnetic pogo pins. The magnetic strip 1133 is included in the base strip 1121 of the device 1120.

[0233] In some embodiments, the device 1120 may be integrated into a cascaded diode valve device 1120' as shown in FIG. 18. The fluidic device 1120' includes cascaded diode valves each including a source pad, a drain pad, which becomes the source pad for the adjacent pad, and a flow controller, that controls the flow of fluid in the lateral direction L from each valve as shown in FIGS. 18 and 19.

[0234] The fluidic device 1120' includes a plurality of sorbent pads 1122, 1124, 1142, 1144, 1146 and flow controllers 1126, 1148, 1150, 1152 that control the flow of fluid in the lateral direction L between each of the respective pads 1122, 1124, 1142, 1144, 1146. The sorbent pads 1122, 1124, 1142, 1144, 1146 are laterally spaced apart to define the respective gaps.

[0235] Each flow controller 1126, 1148, 1150, 1152 includes the respective top and bottom inlet strips, top and bottom outlet strips, a base strip 1121 A, 1121 B, 1121 C, and a connecting strip 1134, 1164, 1174, 1184 as shown in FIGS. 18 and 19. In an illustrative embodiment, each valve has its own base strip 1121 A, 1121 B, 1121C and each of the base strips 1121 A, 1121 B, 1121C is coupled to a bottom strip 1127 as shown in FIGS. 18 and 19. The bottom strip 1127 has holes 1127H or is perforated for contact with the electrodes.

[0236] The fluidic device 1120 further includes a printed circuit board 1192, contact pads 1194, and lighting elements 1198B, 1198R, 1198G as shown in FIGS. 20A and 21-23. The contact pads 1194 are coupled to the printed circuit board 1192 and the conductive strips 1131 A, 1131 B of the associated device 1120. The contact pads 1194 extend through the perforations of the bottom strip 1127.

[0237] In an illustrative embodiment, the device 1120' has a modified diode valve similar to the embodiment in FIGS. 10A-D. The modified section of the fluidic device 520 includes a first sorbent pad 1144, a second sorbent pad 1146, and a flow controller 1152 as shown in FIGS. 18 and 19. The flow controller 1152 further includes a membrane member 1129 as shown in FIGS. 18 and 19.

[0238] FIG. 18 shows an exploded view of the assembled paper, Mylar®, and metallized plastic films which may be cut into individual strips as suggested in FIG. 19. The different sheets of paper, Mylar®, metallized plastic film may be assembled for the fabrication of the cascaded diode device 1120'. FIG. 19 shows the top view and the bottom view of a single strip cut from the assembly if FIG. 18.

[0239] These electroactive diodes 1120' may be assembled to form individual separated, modular diodes or may be assembled as cascaded diodes. FIG. 18 shows a cascaded electroactive fluidic diode device 1120'. FIG. 19 shows the top view and the bottom view of a single cut strip from the cascaded electroactive fluidic diode of FIG. 18.

[0240] The metallized plastic films or conductive strips 1131 A, 1131 B may be included / integrated into the device 1120, 1120' to function as electrodes as these sheets / strips 1131 A, 1131 B are flexible, easy to cut, are economical and commercially produced through roll-to roll manufacturing. Further, the metallized plastic films 1131 A, 1131 B are offered in a wide range of metal coatings and plastic film thicknesses.

[0241] The device 1120 may include copper, aluminum, silver, platinum, and / or palladium metallized films 1131A, 1131 B. The inlet and outlet metallized films or conductive strips 1131 A, 1131 B may comprise one of copper, aluminum, silver, platinum, palladium, and / or any other suitable electrically conductive material. In some embodiments, the inlet conductive strip 1131 A may be a different material than the outlet conductive strip 1131 B. For example, the inlet conductive strip 1131 A may comprise copper material, while the outlet conductive strip 1131 B may comprise silver material. Bare palladium electrodesand inkjet printed silver may also be used for the strips 1131 A, 1131 B in the electroactive microfluidic device 1120.

[0242] The device 1120 may include inlet and outlet metallized films 1131 A, 1131 B that each have a dielectric film. The dielectric film may be composed of or may comprise a self-assembled monolayer, an atomic layer deposited film, or another suitable dielectric film material.

[0243] FIGS. 20A and 20B show the computer programmed sequencing of fluid flow in a cascaded electroactive device 1120'. An illustrative printed circuit board 1192 may be interfaced with the electroactive diode devices 1120, 1120' is shown in FIGS. 20A-23. The printed circuit board 1192 is configured to be interfaced with the fluidic diode device 1120, 1120' as suggested in FIGS. 20A-23. The schematic of the printed circuit board is shown in FIGS. 20A and 20B.

[0244] As shown in FIGS. 20A and 20B, the circuit 1192 includes a voltage divider network that applies the correct activation potential to the contact pads 1194 on the printed circuit board 1192 for turning ON the fluid flow. The circuit also has light elements 1198B, 1198R, 1198G that would indicate the moment voltage has been applied on the contact pad 1194 as shown in Figs. 21- 23. Each lighting element 1198B, 1198R, 1198G may be an LED light in some embodiments. In some embodiments, the light element 1198B, 1198R, 1198G is another suitable lighting element configured to emit light upon activation. The voltage on the contact pad 1194 may be programmatically applied through the use of a microcontroller.

[0245] FIG. 21 shows the printed circuit board 1192 before it is interfaced with the electroactive fluidic diode device 1120'. As shown in FIG. 21 , Neodymium magnets (not shown) have been used on the bottom of the printed circuit board 1192 and copper tape clad magnets 1196 are on the top of the printed circuit board 1192 to have the diode device 1120' make electrical contact with the underlying contact pads 1194 on the printed circuit board 1192. FIG. 19 shows the contact pad areas 1127H on the electroactive fluidic diode device 1120' that may electrical contact with the underlying contact pads 1194 on the printed circuit board 1192.

[0246] The turning ON of the device 1120' indicates that the voltage has been applied on the contact pad 1194 and this in turn lets the corresponding diode valve of the device 1120' to de-pin the solution and spread to the corresponding drain pad as suggested in FIGS. 22 and 23. As shown in FIG. 22, the blue LED light 1198B is lit up or ON which indicates that the blue solution is allowed to move forward. The red and green LED lights 1198R, 1198G will be lit up or ON when the voltage is applied to allow the red or green solution to move forward. This sequence of application of the voltages on the contact pads 1194 may be easily programmed into the microcontroller 1190.

[0247] FIGS. 24A and 24B show an electronically gated fluidic diode device 1120 and the fabrication process of forming the electronically gated fluidic diode device 1120. The fabrication process of the electronically gated fluidic diode device 1120 begins with the preparation of the base strip 1121 , specifically preparing the composite of the magnetic strip 1133 and the support strip 1123, i.e. the Mylar® strip. The process involves carefully adhering the support strip 1123 to the magnetic strip 1133, ensuring uniform contact and expelling any trapped air bubbles to achieve a smooth surface.

[0248] The support strip 1123 or the Mylar® is then cut to the desired dimensions, 22 mm x ~50 mm in an illustrative embodiment, and the doublesided tape is applied to the back side of the magnetic strip 1133 at specific areas. FIGS. 24A and 24B show how and where the double-sided tape strips 1161 A, 1161 B may be applied and an illustrative embodiment of the measurements of the device. Illustrative dimensions and placement of the electronically gated fluidic diode device 1120 are shown in FIGS. 24A and 24B. In some embodiments, the dimensions may vary.

[0249] During the placement of the inlet conductive strip 1131 A, i.e. the copper metal film, particular attention may be used to determine its conductive side. Once identified, the inlet conductive strip 1131 A is aligned with markings on the support strip 1123 and secured in place with the previously applied doublesided tape 1161 A so that the conductive side is exposed to the user. Excess material of the inlet conductive strip 1131 A is folded over the magnet 1133 and trimmed to form a neat and precise fit.

[0250] Similarly, the outlet conductive strip 1131 B, i.e. the silver metal film is prepared with consideration given to identifying its conductive side. The ledge strip 1141 , i.e. double-sided tape, is applied using an overlap method to create a step up design inside the gap 1128 of the device 1120. The outlet conductive strip 1131 B is then aligned with markings on the support strip 1123 and excess material is folded over the magnet 1133 before being trimmed to size.

[0251] Conjugate pads 1122, 1124 are then carefully placed. The bottom inlet strip 1130 and the bottom outlet strip 1136, i.e. double sided tape strips, are used to secure both the drain and source pads 1122, 1124 in their designated positions. Proper spacing between the pads 1122, 1124 may be important to prevent any potential interference or cross-contamination. The drain pad 1124 is arranged so that the drain pad 1122 may lay atop the source pad 1122 of another new diode in a sequential array like as discussed in other embodiments.

[0252] Finally, the connecting strip 1134 is aligned and placed over the assembled components. The top inlet strip 1138 and the top outlet strip 1132, i.e. double sided tape is used to hold the connecting strip 1134 to the source pad 1122 and the drain pad 1124. The top inlet strip 1138 is aligned so that the edge of the top inlet strip 1138 hovers right above where the ledge strip 1141 ends as shown in FIGS. 24A and 24B. This geometric modification induces a sudden change in hydrophobicity, causing the fluid to halt until external force alters the pin conditions. Such force could stem from either a pressure increase, less probable due to volume constraints, or a change in contact angle, more plausible with induced voltage across the metal films 1131 A, 1131 B.

[0253] For a complex multistep assay involving multiple fluid flows within a diagnostic assay device like the device 1120' as shown in FIG. 19, it may be desirable to have a closed loop control and monitoring of the fluid flows within the device 1120' for enhancing the reliability and accuracy of the assay. For this, in addition to electronically activated fluid flows, electronic sensing of the fluid flow through the device 1120, 1120' may be done like as suggested in FIGS. 17A-D. In FIGS. 17A-D, sensing may be easily accomplished through monitoring the impedance across the fluidic diode 1120 through the circuit using a low cost microcontroller.

[0254] FIG. 17 shows a circuit schematic that may be used both for actuation of fluid flows as well as sensing of the fluid flow through the fluidic diode 1120, 1120'. The microcontroller will be essentially used to apply a pulse width modulated (PWM) signal to the fluidic diode through an external resistor as suggested in FIGS. 17A-D.

[0255] For continuous monitoring (sensing) of the fluid flow within the diode 1120, the duty cycle would be made to be less than 20% (preferably 10%). This ensures that the signal applied at the electrodes of the fluidic diode 1120 doesn’t initiate unintended fluid flow / actuation within the fluidic diode 1120. For initiating fluidic flow within the diode 1120, the duty cycle may be increased to 50% like as suggested in FIG. 17C, while still monitoring the impedance across the contacts of the fluidic diode 1120. The sensing signal should be a PWM signal with duty cycle less than or equal to 20% so as to prevent accidental actuation of the fluid flow. Experiments have shown PWM signals with a duty cycle less than 20% does not initiate fluid flows, while allowing reliable measurements of the impedances.

[0256] The circuit schematic is simple enough that any off the shelf microcontroller may be easily deployed to monitor multiple fluidic diodes within the device 1120, 1120'. In a typical operation, the user applies the fluid across the inlet ports interfaced with the source pads of the fluidic diodes within the device like as suggested in FIG. 17A. Fluid enters the air gap 1128 and gets pinned at the stop valve or ledge strip 1141 as shown in FIG. 17B, contacting the drain electrode 1131 B.

[0257] Before making the contact, the signal read across the electrodes of the fluidic diode 1120 would essentially be the applied PWM signal due the circuit being an open circuit. As the solutions traverses the air gap 1128 and gets pinned at the stop valve position, contacting the drain electrode 1131 B, the impedance associated with the electrode-electrolyte interface comes into picture on the microcontroller. The circuit is no longer an open circuit and the appearance of an effective impedance across the contacts of the fluidic diode would reduce the voltage signal being read at its terminal.

[0258] This effective impedance which consists of a capacitive component owing to the double layer capacitance associated at the interface, and whose magnitude is dependent on the surface area of the electrodes being contacted by the fluid will be important in sensing the fluid flow. This sudden drop in the voltage signal read through the microcontroller would indicate that a contact has been successfully made by the fluid. This also indicates that fluidic diode is ready to be applied the actuation signal for actuating fluid flow from the source pas 1122 to the drain pad 1124 of the diode 1120.

[0259] Due to the nature of the stop valve, the fluid will be pinned at the stop valve location until an actuation signal (amounting to a PWM signal with duty cycle > 50%) is applied. Once the actuation potential is applied, like as suggested in FIG. 17C, the fluid overcomes the stop valve or ledge strip 1141 and begins to flow through the gap 1128 into the drain pad 1124.

[0260] During fluid flow as the fluid covers greater surface area over the electrodes within the gap 1128, the capacitance likewise increases thereby increasing the overall impedance across the electrodes of the fluidic diode 1120. This increase in the capacitance will be manifested as an increase in the voltage signal read across the electrodes 1 131 A, 1131 B. Thus, a sudden drop in the voltage signal across the electrode with an increase in the voltage across the electrode upon application of the actuation signal would be indicative of fluid flow from the source pad 1122 to drain pad 1124 within the diode 1120.

[0261] Once all the fluid exits the diode into the source pad 1122, i.e, once all the fluid has been absorbed into the drain pad 1124 and directed to other parts of the fluidic network or device, the fluid dewets within the gap region 1128 and thereby disconnects from the drain electrode 1131 B. This would revert the potential measured across the electrodes 1131 A, 1131 B of the fluidic diode 1120 back to the open circuit values. Thus, continuous monitoring of the voltage signal across the fluidic diode electrodes would give a precise indication of the fluid location, fluid flow and fluid delivery through the entire device 1120, 1120', all of which may be data logged.

[0262] Another embodiment of a fluidic device 1220 in accordance with the present disclosure is shown in FIGS. 25-25C. The fluidic device 1220 issubstantially similar to the fluidic device 20 shown in FIGS. 1-2 and described herein. Accordingly, similar reference numbers in the 1200 series indicate features that are common between the fluidic device 20 and the fluidic device 1220. The description of the device 20 is incorporated by reference to apply to the fluidic device 1220, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1220.

[0263] For the fluidic device 1220 of FIGS. 25-25C there is no temporary pinning of the fluid. Rather, the fluid flows seamlessly in the lateral direction L from the source pad 1222 to the drain pad 1224. The advantage of this embodiment may be that the separation distance between the source pad 1222 and the drain pad 1224 may be made to be extremely small. As long as the source pad 1222 and the drain pad 1224 are not touching, the diode nature of the device 1220 is preserved.

[0264] The fluidic device 1220 includes a source pad 1222, a drain pad 1224, and a flow controller 1226 as shown in FIGS. 25-25C. The flow controller 1226 includes a base strip 1221 , a bottom inlet strip 1230, a top outlet strip 1232, a connecting strip 1234, a bottom outlet strip 1236, and a top inlet strip 1238 as shown in FIGS. 25-25C.

[0265] The source pad 1222 and the drain pad 1224 are coupled to the base strip 1221 in spaced apart relation to define the gap 1228 therebetween. The base strip 1221 is spaced apart from the connecting strip 1234 to define the gap 1228 therebetween. Therefore, the gap 1228 is defined between the source pad 1222, the drain pad 1224, the base strip 1221 , and the connecting strip 1234 as shown in FIGS. 25-25C.

[0266] The bottom inlet strip 1230 is coupled to a bottom surface 1222BS of the source pad 1222. The top outlet strip 1232 is coupled to a top surface 1224TS of the drain pad 1224. The bottom outlet strip 1236 is coupled to a bottom surface 1224BS of the drain pad 1224. The top inlet strip 1238 is coupled to a top surface 122STS of the source pad 1222.

[0267] The bottom inlet strip 1230 is coupled to a bottom surface 1222BS of the source pad 1222 and the surface 1221S of the base strip 1221 so that the bottom inlet strip 1230 is located between the source pad 1222 and the basestrip 1221. The bottom outlet strip 1236 is coupled to a bottom surface 1224BS of the drain pad 1224 and the surface 1221S of the base strip 1221 so that the bottom outlet strip 1236 is located between the drain pad 1224 and the base strip 1221.

[0268] Both the base strip 1221 and the connecting strip 1234 extend between the source pad 1222 and the drain pad 1224 on top and bottom sides of the source pad 1222 and the drain pad 1224 to bridge the air gap 1228 therebetween as shown in FIGS. 25-25C. The base strip 21 extends from a first or outlet end 12210 coupled to the bottom outlet strip 1236 on the drain pad 1224 to a second or inlet end 12211 coupled to the bottom inlet strip 1230 on the source pad 1222 to bridge the air gap 28 between the source pad 1222 and the drain pad 1224 on a bottom side of the air gap 1228 as shown in FIGS. 25-25C. The connecting strip 34 extends from a first or outlet end 12340 coupled to the top outlet strip 1232 on the drain pad 1224 to a second or inlet end 12341 coupled to the top inlet strip 1238 of the source pad 1222 to bridge the gap 1228 between the source pad 1222 and the drain pad 1224 on a top side of the air gap 1228 as shown in FIGS. 25-25C. In this way, the fluid flows in the lateral direction L along a flow surface 1234S of the connecting strip 1234 and a flow surface 1221S of the base strip 1221 that face the gap 1228 when the fluid is applied to the source pad 1222 as shown in FIGS. 25-25C.

[0269] Unlike the embodiment of FIGS. 1 -2, the flow of fluid is not temporarily pinned at the source pad 1222 as suggested in FIG. 25B. The top and bottom inlet strips 1230, 1238 do not extend past an outer edge 1222E1 of the source pad 1222 into the air gap 1228 as shown in FIGS. 25-25C. The outer edge 1222E1 of the source pad 1222 is offset from the edges of the top and bottom inlet strips 1230, 1238 such that the fluid flows along the surfaces 1221 S, 1234S to allow the flow of fluid to seamlessly flow into the air gap 1228.

[0270] The top and bottom inlet strips 1230, 1238 do not block the flow of fluid into the gap 1228. The fluid still flows in the lateral direction L along the flow surface 1221S of the base strip 1221 and the flow surface 1234S of the connecting strip 234 that face the gap 228 when the fluid is applied to the source pad 222. Because the outer end 1222E1 of source pad 1222 extends past thetop and bottom inlet strips 1230, 1238, the top and bottom inlet strips 1230, 1238 do not temporarily pin the fluid at the source pad 1222. Rather, the capillary driven flow through the sorbent pad 1222 is seamlessly converted to surface directed flows through the gap 1228 along the base strip 1221 and the connecting strip 1234.

[0271] The top and bottom outlet strips 1232, 1236 are at least flush with an outer edge 1224E2 of the drain pad 1224 as shown in FIGS. 25-25C. Having the top and bottom outlet strips 1232, 1236 being at least flush with the outer edge 1224E2 of the drain pad 1224 provides the best fluid tension properties to form the burst valve and prevent backward flow. The fluid applied to the source pad 1222 may comprise surfactants (about ).1 %) which may reduce the surface tension thereby increasing the spreading and wetting properties to help with the dried reagents. The flush top and bottom outlet strips 1232, 1236 help increase the fluidic tension properties at the drain pad 1224 to prevent backward flow into the gap 1228. In some embodiments, the top outlet strip 1232 may extend into the gap 1228.

[0272] The top and bottom outlet strips 1232, 1236 cooperate to provide a burst valve that prevents the fluid from flowing opposite the lateral direction L back towards the source pad 1222 as shown in FIGS. 25-25C. The top outlet strip 1232 cooperates with the bottom outlet strip 1236 to prevent the fluid from flowing opposite the lateral direction L back towards the source pad 1222 as shown in FIGS. 25A-C. The top outlet strip 1232 and the bottom outlet strip 1236 thereby provide a burst valve that prevents the fluid from flowing opposite to the desired direction L so that the device 1220 may be integrated into existing lateral flow assay formats, vertical flow assay formats, or other suitable applications.

[0273] As shown in FIGS. 25-25C, the gap 1128 is open on the sides. In other words, no connecting strips are coupled to the sides of the source pad 1122 and the drain pad 1124.

[0274] In some embodiments, like as shown in FIGS. 26A and 26B, the fluidic diode device 1220 may include connecting side strips 1281 , 1283 coupled to respective outer edges 1222E3, 1222E4 of the source pad 1222 and the outer edges 1224E3, 1224E4 drain pad 1224 to partially close the air gap 1228between the source pad 1222 and the drain pad 1224 on the sides of the device 1220.

[0275] If the fluidic diode device 1220 includes connecting side strips 1281 , 1283, the device 1220 includes air vents 1293 for fluid flow. As shown in FIG. 26A, there are air vents 1293 to the air gap 1228. The air vents 1293 may be in another location in other embodiments.

[0276] However, the connecting side strips 1281 , 1283 may cause the device 1220 to leak. Therefore, the connecting side strips 1281 , 1283 are configured to be coupled to the respective outer edges 1222E3, 1222E4 of the source pad 1222 and the outer edges 1224E3, 1224E4 drain pad 1224 with inlet and outlet side strips 1285, 1287, 1289, 1291 that are like the other inlet and outlet strips to help prevent leakage. In other illustrative embodiments, the air gap between the source pad and the drain pad is open on either side of the air gap.

[0277] Another embodiment of a fluidic device 1320 in accordance with the present disclosure is shown in FIG. 27. The fluidic device 1320 is substantially similar to the fluidic device 20 shown in FIGS. 1-2 and the fluidic device 1220 as shown in FIGS. 25-25C and described herein. Accordingly, similar reference numbers in the 1300 series indicate features that are common between the fluidic devices 20, 1220 and the fluidic device 1320. The description of the devices 20, 1220 is incorporated by reference to apply to the fluidic device 1320, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1320.

[0278] As shown in FIG. 27, a valve like the valve 1220 is incorporated into a lateral flow assay device 1320. The device 1320 includes a source pad 1322, a drain pad 1324, a conjugate pad 1342, an absorbent pad 1344, and a flow controller 1326 as shown in FIG. 27. The flow controller 1326 includes a base strip 1321 , top and bottom inlet strips 1338, 1330, top and bottom intermediate strips 1362, 1360, top and bottom outlet strips 1332, 1336, a connecting strip 1334, and a membrane member 1329 as shown in FIG. 27.

[0279] The source pad 1322, the drain pad 1324, the conjugate pad 1342, and the absorbent pad 1344 are coupled to the base strip 1321 in spaced apartrelation to define respective gaps 1328A, 1328B, 1328C therebetween. The first gap 1328A is defined between the source pad 1322 and the conjugate pad 1342. The second gap 1328B is defined between the conjugate pad 1342 and the drain pad 1324. The third gap 1328C is defined between the drain pad 1324 and the absorbent pad 1344. The connecting strip 1334 extends between the source pad 1322, the conjugate pad 1342, and the drain pad 1324 and is spaced apart from the base strip 1321 to define the gaps 1328A, 1328B therebetween.

[0280] Therefore, the gap 1328A is defined between the source pad 1322, the conjugate pad 1342, the base strip 1321 , and the connecting strip 1334 as shown in FIG. 27. The gap 1328B is defined between the conjugate pad 1342, the drain pad 1324, the base strip 1321 , and the connecting strip 1334 as shown in FIG. 27.

[0281] The bottom inlet strip 1330 is coupled to a bottom surface of the source pad 1322. The top outlet strip 1332 is coupled to a top surface of the drain pad 1324. The bottom outlet strip 1336 is coupled to a bottom surface of the drain pad 1324. The top inlet strip 1338 is coupled to a top surface of the source pad 1322. The bottom intermediate strip 1360 is coupled to a bottom surface of the conjugate pad 1342. The top intermediate strip 1362 is coupled to a top surface of the conjugate pad 1342.

[0282] The bottom inlet strip 1330 is coupled to a bottom surface of the source pad 1322 and the surface 1321 S of the base strip 1321 so that the bottom inlet strip 1330 is located between the source pad 1322 and the base strip 1321. The bottom outlet strip 1336 is coupled to a bottom surface of the drain pad 1324 and the surface 1321 S of the base strip 1321 so that the bottom outlet strip 1336 is located between the drain pad 1324 and the base strip 1321 . The bottom intermediate strip 1360 is coupled to a bottom surface of the conjugate pad 1342 and the surface 1321 S of the base strip 1321 so that the bottom outlet strip 1336 is located between the conjugate pad 1342 and the base strip 1321.

[0283] Both the base strip 1321 and the connecting strip 1334 extend between the source pad 1322, the conjugate pad 1342, and the drain pad 1324 on top and bottom sides of the source pad 1322, the conjugate pad 1342, andthe drain pad 1324 to bridge the air gaps 1328A, 1328B therebetween as shown in FIG. 27. The base strip 21 extends from a first or outlet end 13210 coupled to the bottom outlet strip 1336 on the drain pad 1324 to a second or inlet end 13211 coupled to the absorbent pad 1344 to bridge the air gaps 1328A, 1328B. The connecting strip 34 extends from a first or outlet end 13340 coupled to the top outlet strip 1332 on the drain pad 1324 to a second or inlet end 13341 coupled to the top inlet strip 1338 of the source pad 1322 to bridge the air gaps 1328A, 1328B. In this way, the fluid flows in the lateral direction L along a flow surface 1334S of the connecting strip 1334 and a flow surface 1321 S of the base strip 1321 that face the gaps 1328A, 1328B when the fluid is applied to the source pad 1322.

[0284] The membrane member 1329 is coupled to the base strip 1321 as shown in FIG. 27. The membrane member 1329 extends between the drain pad 1324 and the absorbent pad 1344 as shown in FIG. 27. In an illustrative embodiment, the drain pad 1324 and the absorbent pad 1344 overlap the membrane member 1329.

[0285] In an illustrative embodiment, the flow controller 1326 further includes a protrusion 1340 as shown in FIG. 27. The protrusion 1340 extends from the flow surface 1334S of the connecting strip 1334 into the gap 1328A between the source pad 1322 and the conjugate pad 1342. The protrusion 1340 extends perpendicular to the flow of the fluid and is configured to slow the flow of the fluid from the source pad 1322 to the conjugate pad 1342. In some embodiments, the protrusion 1340 may extend from the flow surface 1321 S of the base strip 1321 into the gap 1328A between the source pad 1322 and the drain pad 1324.

[0286] FIG. 27 shows a device 1320 that interfaces of a fluidic diode with a conventional lateral flow assay. The fluidic diode valve section of the device 1320 decouples the sample flow from the conjugate flow as suggested in FIGS. 27A-I. As shown in FIGS. 27A and 27B, the sample S is deposited over the drain or sample pad 1324 so that the sample flows through the nitrocellulose membrane member 1329 of the lateral flow assay. As shown in FIG. 27C, deposition of the buffer solution B over the source pad 1322 of the fluidic diodevalve section would flow the buffer solution through the air gap 1328A, into the conjugate pad 1342, seamlessly into the sample pad 1324 and the nitrocellulose member 1329 as suggested in FIGS. 27C-I. Here seamless forward flow geometry has been incorporated with possible time delays incorporated through the protrusions 1340 on the connecting strip 1334.

[0287] In some embodiments, the source or buffer pad 1322 may function as the conjugate pad 1342. In other words, the conjugate may be in the source pad 1322 and the intermediate conjugate pad 1342 may be omitted.

[0288] As shown in FIGS. 28 and 28A, another embodiment of the device 1320' may incorporate a filter 1371 and a vertical flow controller 1373. The filter 1371 is arranged vertically above the drain or sample pad 1324 with a vertical gap 1328V therebetween. The vertical flow controller 1373 is arranged between the filter 1371 and the sample pad 1324 to control a flow of the sample S in a vertical direction V from the filter 1371 to the sample pad 1324 across the vertical gap 1328V therebetween to prevent the sample from flowing opposite the vertical direction V back towards the filter 1271 .

[0289] The vertical flow controller includes two hydrophilic strips 1377A, 1377B arranged between two tape strips 1375A, 1375B, 1379A, 1779B as shown in FIG. 28. The hydrophilic strips 1377A, 1377B are spaced apart a distance D. One tape strip 1375A, 1375B couples the corresponding hydrophilic strip 1377A, 1377B to the drain pad 1324. The other tape strip 1379A, 1379B couples the corresponding hydrophilic strip 1377A, 1377B to a bottom surface 1371S of the filter 1371.

[0290] The vertical fluidic diode section including the filter 1371 and vertical flow controller 1373, allows the fluid to flow from the top to the bottom or vertical direction V as shown in FIG. 28. The filter 1371 may be a blood separator. The filter 1371 may be integrated with a decoupled lateral flow assay as shown in FIG. 28. Since the fluid is allowed to flow from the top to the bottom, the blood filter 1371 will filter out the blood cells allowing the serum to flow through into the sample pad 1324 and into the nitrocellulose member 1329. Conjugate flow would flow laterally in the lateral direction L through the device1320', the fluidic diode nature of the vertical fluidic diode preventing flow of the conjugate into the filter 1371 .

[0291] Another embodiment of a fluidic device 1420 in accordance with the present disclosure is shown in FIG. 29. The fluidic device 1420 is substantially similar to the fluidic device 20 shown in FIGS. 1-2, the fluidic device 1220 as shown in FIGS. 25-25C, and the fluidic device 1320 as shown in FIG. 27 and described herein. Accordingly, similar reference numbers in the 1400 series indicate features that are common between the fluidic devices 20, 1220, 1320 and the fluidic device 1420. The description of the devices 20, 1220, 1320 is incorporated by reference to apply to the fluidic device 1420, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1420.

[0292] FIG. 29 shows how modular fluidic diodes may be interfaced with other sections of a paper based device without the use of an extending paper strip. The device 1420 as shown in FIG. 29 includes a fluidic diode valve interfaced with a paper based device 1447. The paper based device 1447 includes a lateral flow assay sample pad 1424 that forms the drain pad 1424 of the device 1420. In an illustrative embodiment, the fluidic diode valve flows to the lateral flow assay.

[0293] The device 1420 includes a source pad 1422, a drain pad 1424, a conjugate pad 1442, and a flow controller 1426 as shown in FIG. 29. The flow controller 1426 includes a base strip 1421 , top and bottom inlet strips 1438, 1430, top and bottom intermediate strips 1462, 1460, top and bottom outlet strips 1432, 1436, and a connecting strip 1434 as shown in FIG. 29.

[0294] The source pad 1422 and the conjugate pad 1442 are coupled to the base strip 1421 in spaced apart relation to define the respective gap 1428A therebetween. The flow controller 1426 is coupled to the drain pad 1424 on its own base in an illustrative embodiment and is spaced apart from the conjugate pad 1442 to define the respective air gap 1428B.

[0295] The first gap 1428A is defined between the source pad 1422 and the conjugate pad 1442. The second gap 1428B is defined between the conjugate pad 1442 and the drain pad 1424. The connecting strip 1434 extendsbetween the source pad 1422, the conjugate pad 1442, and the drain pad 1424 and is spaced apart from the base strip 1421 to define the gaps 1428A, 1428B therebetween.

[0296] Therefore, the gap 1428A is defined between the source pad 1422, the conjugate pad 1442, the base strip 1421 , and the connecting strip 1434 as shown in FIG. 27. The gap 1428B is defined between the conjugate pad 1442, the drain pad 1424, the base strip 1421 , and the connecting strip 1434 as shown in FIG. 27.

[0297] Compared to the devices 1320, 1320' in FIGS. 27 and 28, the fluidic diode is integrated with the lateral flow assay at an angle as shown in FIG. 29. The fluidic diode is integrated with the lateral flow assay at a right angle as shown in FIG. 29. The drain pad 1424 is a part of the lateral flow assay sample pad that leads to the lateral flow assay part of the device 1420.

[0298] Both the base strip 1421 and the connecting strip 1434 extend between the source pad 1422, the conjugate pad 1442, and the drain pad 1424 on top and bottom sides of the source pad 1422, the conjugate pad 1442, and the drain pad 1424 to bridge the air gaps 1428A, 1428B therebetween as shown in FIG. 29. The base strip 21 extends from a first or outlet end 14210 that abuts a base strip of the drain or lateral flow sample pad 1424 to a second or inlet end 14211 coupled to the absorbent pad 1444 to bridge the air gaps 1428A, 1428B. The connecting strip 34 extends from a first or outlet end 14340 coupled to the top outlet strip 1432 on the drain pad 1424 to a second or inlet end 14341 coupled to the top inlet strip 1438 of the source pad 1422 to bridge the air gaps 1428A, 1428B.

[0299] In this way, the fluid flows in the lateral direction L along a flow surface 1434S of the connecting strip 1434 and a flow surface 1421S of the base strip 1421 that face the gaps 1428A, 1428B when the fluid is applied to the source pad 1422. The outlet end 14340 of the connecting strip 1434 couples to the top outlet strip 1432 on the drain pad 1424 to connect the modular fluidic diode to the lateral flow assay sample pad 1424.

[0300] Another embodiment of a fluidic device 1520 in accordance with the present disclosure is shown in FIG. 30. The fluidic device 1520 issubstantially similar to the fluidic device 20 shown in FIGS. 1-2, the fluidic device 1120 as shown in FIGS. 16A-C and the fluidic device 1420 as shown in FIG. 29 and described herein. Accordingly, similar reference numbers in the 1500 series indicate features that are common between the fluidic devices 20, 1120, 1420 and the fluidic device 1520. The description of the devices 20, 1120, 1420 is incorporated by reference to apply to the fluidic device 1520, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1520.

[0301] FIG. 30 shows how modular fluidic diodes may be interfaced with other sections of a paper based device without the use of an extending paper strip. The device 1520 as shown in FIG. 30 includes an electroactive fluidic diode interfaced with a paper based device 1547. The paper based device 1547 includes a lateral flow assay sample pad 1524 that forms the drain pad 1524 of the device 1520. In an illustrative embodiment, the electroactive fluidic diode valve flows to the lateral flow assay.

[0302] The device 1520 includes a source pad 1522, a drain pad 1524, a conjugate pad 1542, and a flow controller 1526 as shown in FIG. 30. The flow controller 1526 includes a base strip 1521 , top and bottom inlet strips 1538, 1530, top and bottom intermediate strips 1562, 1560, top and bottom outlet strips 1532, 1536, and a connecting strip 1534 as shown in FIG. 30. The base strip 1521 includes a support strip or layer 1523, the conductive strips 1531 A, 1531 B, the magnetic strip 1533, and the ledge strip 1541 as shown in FIG. 30.

[0303] The source pad 1522 and the conjugate pad 1542 are coupled to the base strip 1521 in spaced apart relation to define the respective gap 1528A therebetween. The flow controller 1526 is coupled to the drain pad 1524 on its own base in an illustrative embodiment and is spaced apart from the conjugate pad 1542 to define the respective air gap 1528B.

[0304] The first gap 1528A is defined between the source pad 1522 and the conjugate pad 1542. The second gap 1528B is defined between the conjugate pad 1542 and the drain pad 1524. The connecting strip 1534 extends between the source pad 1522, the conjugate pad 1542, and the drain pad 1524and is spaced apart from the base strip 1521 to define the gaps 1528A, 1528B therebetween.

[0305] Therefore, the gap 1528A is defined between the source pad 1522, the conjugate pad 1542, the base strip 1521 , and the connecting strip 1534 as shown in FIG. 30. The gap 1528B is defined between the conjugate pad 1542, the drain pad 1524, the base strip 1521 , and the connecting strip 1534 as shown in FIG. 30.

[0306] Compared to the devices 1320, 1320' in FIGS. 27 and 28, the fluidic diode is integrated with the lateral flow assay at an angle as shown in FIG. 30. The fluidic diode is integrated with the lateral flow assay at a right angle as shown in FIG. 30. The drain pad 1524 is a part of the lateral flow assay sample pad that leads to the lateral flow assay part of the device 1520.

[0307] Both the base strip 1521 and the connecting strip 1534 extend between the source pad 1522, the conjugate pad 1542, and the drain pad 1524 on top and bottom sides of the source pad 1522, the conjugate pad 1542, and the drain pad 1524 to bridge the air gaps 1528A, 1528B therebetween as shown in FIG. 30. The base strip 21 extends from a first or outlet end 15210 that abuts a base strip of the drain or lateral flow sample pad 1524 to a second or inlet end 15211 coupled to the absorbent pad 1544 to bridge the air gaps 1528A, 1528B. The connecting strip 34 extends from a first or outlet end 15340 coupled to the top outlet strip 1532 on the drain pad 1524 to a second or inlet end 15341 coupled to the top inlet strip 1538 of the source pad 1522 to bridge the air gaps 1528A, 1528B.

[0308] In this way, the fluid flows in the lateral direction L along a flow surface 1534S of the connecting strip 1534 and a flow surface defined by the surface 1521S of the support strip 1523 and the surface 1531 S of the conductive strip 1531 A that face the gaps 1528A, 1528B when the fluid is applied to the source pad 1522. The outlet end 15340 of the connecting strip 1534 couples to the top outlet strip 1532 on the drain pad 1524 to connect the modular fluidic diode to the lateral flow assay sample pad 1524. The electroactive fluidic diode can be used to activate fluid flow to the lateral flow assay by applying the voltage across the electrodes 1531 A, 1531 B.

[0309] Another embodiment of a fluidic device 1620 in accordance with the present disclosure is shown in FIG. 31 . The fluidic device 1620 is substantially similar to the fluidic device 20 shown in FIGS. 1-2, the fluidic device 1120 as shown in FIGS. 16A-C, the fluidic device 1420 as shown in FIG. 29, and the fluidic device 1520 as shown in FIG. 30 and described herein. Accordingly, similar reference numbers in the 1600 series indicate features that are common between the fluidic devices 20, 1120, 1420, 1520 and the fluidic device 1620.The description of the devices 20, 1120, 1420, 1520 is incorporated by reference to apply to the fluidic device 1620, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1620.

[0310] FIG. 31 shows how modular fluidic diodes may be interfaced with other sections of a paper based device without the use of an extending paper strip. The device 1620 as shown in FIG. 31 includes an electroactive fluidic diode interfaced with a paper based device 1647. The paper based device 1647 includes a lateral flow assay sample pad 1624 that forms the source pad 1622 of the device 1620. In an illustrative embodiment, the lateral flow assay flows to the electroactive fluidic diode valve.

[0311] The device 1620 includes a source pad 1622, a drain pad 1624, a conjugate pad 1642, and a flow controller 1626 as shown in FIG. 31. The flow controller 1626 includes a base strip 1621 , top and bottom inlet strips 1638, 1630, top and bottom intermediate strips 1662, 1660, top and bottom outlet strips 1632, 1636, and a connecting strip 1634 as shown in FIG. 31 . The base strip 1621 includes a support strip or layer 1623, the conductive strips 1631A, 1631 B, the magnetic strip 1633, and the ledge strip 1641 as shown in FIG. 31.

[0312] The conjugate pad 1642 and the drain pad 1624 are coupled to the base strip 1621 in spaced apart relation to define the respective gap 1628 therebetween. The flow controller 1626 is coupled to the source pad 1622 on its own base in an illustrative embodiment and is spaced apart from the conjugate pad 1642. In an illustrative embodiment, there is a small gap between the conjugate pad 1642 and the source pad 1622, but the source pad 1622 extends past the top inlet strip 1638 so that forward flow is allowed. In some embodiments, the conjugate pad 1642 abuts the source pad 1622.

[0313] The gap 1628 is defined between the conjugate pad 1642 and the drain pad 1624. The connecting strip 1634 extends between the source pad 1622, the conjugate pad 1642, and the drain pad 1624 and is spaced apart from the base strip 1621 to define the gap 1628. Therefore, the gap 1628 is defined between the conjugate pad 1642, the drain pad 1624, the base strip 1621 , and the connecting strip 1634 as shown in FIG. 31 .

[0314] Compared to the devices 1320, 1320' in FIGS. 27 and 28, the fluidic diode is integrated with the lateral flow assay at an angle as shown in FIG. 31. The fluidic diode is integrated with the lateral flow assay at a right angle as shown in FIG. 31 . The source pad 1622 is a part of the lateral flow assay sample pad that leads to the lateral flow assay part of the device 1620.

[0315] Both the base strip 1621 and the connecting strip 1634 extend between the source pad 1622, the conjugate pad 1642, and the drain pad 1624 on top and bottom sides of the source pad 1622, the conjugate pad 1642, and the drain pad 1624 to bridge the air gaps 1628A, 1628B therebetween as shown in FIG. 31 . The base strip 21 extends from a first or outlet end 16210 coupled to a bottom outlet strip 1636 on the drain pad 1624 to a second or inlet end 16211 that abuts a base strip of the source or lateral flow sample pad 1622 to bridge the air gaps 1628. The connecting strip 34 extends from a first or outlet end 16340 coupled to the top outlet strip 1632 on the drain pad 1624 to a second or inlet end 16341 coupled to the top inlet strip 1638 of the source pad 1622 to bridge the air gaps 1628A, 1628B.

[0316] In this way, the fluid flows in the lateral direction L along a flow surface 1634S of the connecting strip 1634 and a flow surface defined by the surface 1621S of the support strip 1623 and the surface 1631S of the conductive strip 1631 A that face the gaps 1628A, 1628B when the fluid is applied to the source pad 1622. The outlet end 16340 of the connecting strip 1634 couples to the top outlet strip 1632 on the drain pad 1624 to connect the modular fluidic diode to the lateral flow assay sample pad 1624. The electroactive fluidic diode can be used to activate fluid flow from the lateral flow assay by applying the voltage across the electrodes 1631A, 1631 B.FIG. 29

[0317] Another embodiment of a fluidic device 1720 in accordance with the present disclosure is shown in FIGS. 32 and 33. The fluidic device 1720 is substantially similar to the fluidic device 20 shown in FIGS. 1-2, the fluidic device 520 as shown in FIGS. 10A-D, the fluidic device 1120 as shown in FIGS. 16A-C, and the fluidic device 1220 as shown in FIGS. 25-25C and described herein. Accordingly, similar reference numbers in the 1700 series indicate features that are common between the fluidic devices 20, 520, 1120, 1220 and the fluidic device 1720. The description of the devices 20, 520, 1120, 1220 is incorporated by reference to apply to the fluidic device 1720, except in instances when it conflicts with the specific description and the drawings of the fluidic device 1720.

[0318] FIGS. 32 and 33 shows how modular electroactive valves or passive fluidic diode valves may be integrated with vertical flow dispenser. Electroactive fluidic diodes or passive time delayed fluidic diodes may be interfaced with a sample pad. The arrows in FIGS. 32 and 33 show the flow direction through the device 1720.

[0319] The device 1720 includes a source pad 1722, a drain pad 1724, and a flow controller 1726 as shown in FIGS. 32 and 33. The flow controller 1726 includes a base strip 1721 , top and bottom inlet strips 1738, 1730, top and bottom outlet strips 1732, 1736, a connecting strip 1734, and a membrane member 1729 as shown in FIGS. 32 and 33. The base strip 1721 is an absorbent pad or glass fiber pad that is coupled to or adhered with the membrane member 1729.

[0320] In some embodiments, the fluidic devices 20, 220, 320, 420, 520, 620, 720, 820 of the present application may be hybrid - paper-plastic "fluidic diode" modules. The modules may be assembled into a diagnostic assay to automate the performance of the assays with minimal user intervention. Such fluidic diodes may be configured into lateral flow, vertical flow or nucleic acid amplification and testing (NAAT) diagnostic devices to significantly expand their scope for a myriad of diagnostic and sensing applications at the point of care. Further, the construction / fabrication of the fluidic devices 20, 220, 320, 420, 520, 620, 720, 820 may be simple and only slightly deviate from the manner of fabrication of the existing assays. Nonetheless, incorporation of these devices20, 220, 320, 420, 520, 620, 720, 820 may provide additional functionality that would enable one to perform complex, multistep FLA, VFA and / or NAAT.

[0321] The fluidic devices 20, 220, 320, 420, 520, 620, 720, 820 of the present application may be integrated into bed-side diagnostics (commercial applications), personalized medicine, diagnostics for resource poor locations (ex, poor countries, soldiers on the field, etc.), food and water safety, etc. The integration of the fluidic diode valves I devices 20, 220, 320, 420, 520, 620, 720, 820 into lateral flow and vertical flow device architectures may provide more flexibility in performing complex, multistep assays within inexpensive and user- friendly assay formats, while enhancing the sensitivity of the assays. Further, electronic control of fluid flows within these devices make them particularly suitable for incorporation within NAAT point of care assays.

[0322] The fluidic devices 20, 220, 320, 420, 520, 620, 720, 820 of the present application involve a relatively simplistic construction using inexpensive materials, such as plastics, glass fiber pads, and / or cellulosic materials. These devices 20, 220, 320, 420, 520, 620, 720, 820 may be fabricated in a high through-put modular format and be seamlessly integrated into existing lateral flow and vertical flow assay formats. Thus, with a modest change in fabrication of existing LFAs and VFAs, greater flexibility and control may be achieved.

[0323] The design of certain devices disclosed herein, such as the device 20 of FIG. 1 , is such that the devices may be realized in high throughput and cut to individual modular units, akin to how lateral flow assays are fabricated. For example, the device 20 seamlessly integrates paper and plastic where the lateral capillary driven flow through the sorbent pad 22 is seamlessly converted to surface directed flows within the plastic regions, i.e. the base strip 21 and the connecting strip 34.

[0324] An individual diode valve comprises a source paper (conjugate) pad 22 and a drain sorbent pad 24 wherein the source pad 22 serves to store the dried reagents. Dried reagents may be reconstituted through the addition of the buffer solution during the performance of the assay. The discrete source and drain paper segments 22, 24 are bridged together by the base strip 21 and the connecting strip 34 and the double sided adhesive tape layers 30, 32, 36, 38 toform the flow control means for transporting the flow of the fluid in the lateral direction L from the source pad 22 to the drain pad 24 across the air gap 28 formed therebetween while preventing the flow of fluid from flowing opposite the lateral direction L back towards the source pad 22 so that the fluid only flows in the lateral direction L from the source pad 22 to the drain pad 24 as shown in FIGS. 1-1C. The discrete source and drain paper segments 22, 24 are further bridged asymmetrically with an overlaying plastic strip 34 and double sided adhesive tape 32. The connecting strip 34 and the base strip 21 may comprise a hydrophilic plastic material, such as Mylar®.

[0325] The asymmetry comes from the manner in which the base strip 21 and the overlaid connecting strip 34 bridges the two source and drain pads 22, 24 and resulting in the diode like behavior of the device 20. As shown in FIGS. 1A-C, the desired direction of flow is from the source pad 22 to the drain pad 24. The bridging connecting strip 34 is applied with a thin hydrophobic double sided tape or top outlet strip 32 only on one edge 340. The top outlet strip 32 is then aligned such that the top outlet strip 32 comes in contact with the drain pad 24 with a slight overhang into the gap region 28 as shown in FIG. 1 . The other side 34I of the connecting strip 34 overlays the source pad 22 without actually being taped down to the source pad 22. In some embodiments, as shown in FIG. 4, the second end 234I may be taped down with the top inlet strip 238 so as to provide a “negative overhang.” The negative overhand may provide opportunity to control the flow rate into the air gap, while preserving the unidirectional operation of the device 220.

[0326] To use the device 20, the source and drain pads 22, 24 may be initially saturated with an aqueous solution. The device 20 should permit the flow only in one direction, from source pad 22 to the drain pad 24.

[0327] The flow through the porous sorbent pads 22, 24 follows Darcy’s law. Here, the porous material (e.g., paper) of the source pad 22 and the drain pad 24 may include a number of small intersecting capillaries that help in the passive transport of fluid through capillary action when dry.

[0328] Once saturated however, fluid is trapped within the sorbent pad 22, 24 and held fast through capillary pressure at the liquid-air interface of each ofthe individual pores at the interface. Excess pressure that exceeds the summated capillary burst pressure of each of these individual capillaries needs to be applied for the fluid to move past from the discrete pad 22.

[0329] As shown in FIG. 1 , the connecting strip 24 overlaying the source pad 22 forms a narrow inlet air gap G with the source pad 22. Excess applied solution gets instantly driven into the gap G through capillary attractive forces. It is intermittently or temporarily pinned as shown in FIG. 1 B as it contacts the bottom inlet strip 30 owing to an abrupt change in the contact angle of the advancing fluid.

[0330] Once critical pressure at the fluid front is reached, pushing the fluid to contact the base strip 21 , or the surface 21 S, below the connecting strip 34, surface directed capillary flows pull the liquid through the gap 28 region and into the drain pad 24. The resistance to flow and hence the velocity of the fluid front through the gap 28 depends on the surface roughness as well as the surface energy of the connecting strip 34, both of which may be controlled to control the speed of the flow of the fluid through the air gap 28. The surface roughness as well as the surface energy of the base strip 21 may also be controlled similar to the connecting strip 34 to control the speed of the flow of the fluid through the air gap 28.

[0331] On the other hand, the asymmetric layout of the flow controller 26 further prevents backward flow (flow from the drain pad 24 to the source pad 22) through the fluidic device 20. The manner in which the top outlet strip 32 and the bottom outlet strip 36 are applied on the drain pad 24 essentially creates a burst valve for fluid flow in the reverse direction (drain to source). The hydrophobicity of the double-sided adhesive of the top outlet strip 32 and the bottom outlet strip 36 as well as the finite thickness of the strips 32, 36 may create a substantially large burst pressure for fluid flow in the reverse direction that is not met by the volume of fluids used in typical assays.

[0332] Here, the top and bottom outlet strips 32, 36 used have a hydrophobic surface (surface contact angles with water droplet > 90°) and the overhang of the top outlet strip 32 and the associated non-negligible thickness of the top outlet strip 32 essentially creates a capillary burst valve at the input end24E2 of the drain pad 24. As a result, this modular unit 20 serves as a unidirectional fluidic diode wherein fluid flows within the device occur in a single direction.

[0333] FIGS. 7A-C show the fluidic diode valves integrated into a lateral flow assay format. For the performance of the sequential assay, the end user may initially deposit few drops of the buffer solution over the various sorbent pads 422, 424, 442, 444, 446 going from the rightmost paper segment (closest to the absorbent / wicking pad). As backward flow is prevented, flow begins and proceeds in a direction from left to right.

[0334] As each of the individual sorbent pads 422, 424, 442, 444, 446 have been pre-saturated by the user, the excess pressure applied would move the fluid through each of the discrete sorbent pads 422, 424, 442, 444, 446 in a sequential manner and unidirectionally. The fluid from the first sorbent pad 422 on the left moving into the gap 428 pushing the fluid from the next adjoining segment 424 into its adjoining gap 454 and so on. Thus, this establishes a movement of the fluids from each of the sorbent pads 422, 424, 442, 444 through the detection zone and eventually into the absorbent pad 446. FIGS. 7-9 show the cascaded diode valves may be seamlessly integrated into the existing lateral flow assays manufacturing.

[0335] Similar to fluid flows occurring within microfluidic channels supporting laminar flows where mixing between flowing adjacent fluids occur predominantly through diffusion, mixing between fluids in adjacent paper regions occurs through diffusion, which is an inherently slow process. Therefore, even though the fluids from adjacent regions come into contact during the lateral flow, mixing between them may still be slow and diffusion limited. Therefore, serious contamination may be ruled out. To further mitigate contamination, plain buffer solution may be placed between two reagent zones thereby serving to minimize direct mixing of the reagent together while functioning as the intermediate wash buffer solution.

[0336] In FIG. 7, the cascaded fluidic diodes may be configured to be a self-contained lateral flow assay by incorporating the conjugate pad and the nitrocellulose membrane during the fabrication process. In FIGS. 8 and 9, thecascaded fluidic diodes may be interfaced with conventional lateral flow assays to further enhance the functionality (sensitivity and limit of detection) if these assays. In FIGS. 8 and 9, the cascaded fluidic diodes may be separately fabricated and then interfaced with existing conventional LFA in two different ways.

[0337] In FIG. 8, the cascaded fluidic diodes are fabricated such that the last drain pad extends beyond the base Mylar® support. This extension may serve to readily establish the connection between the cascaded diode valve and the conventional LFA. FIG. 9 shows an alternative interfacing arrangement that includes a paper bridge to link the cascaded diode valve to the conventional LFA.

[0338] An alternative to lateral flow assays, vertical flow assays have been developed and are gaining in popularity owing to the extensive multiplexing capabilities offered. Despite being touted as the next generation rapid tests, a major limitation precluding widespread adoption of vertical flow assays may lie in the complex operation and the need for human intervention during the performance of the assay.

[0339] Thus, these lack the user-friendliness that conventional lateral-flow assays offer. Engineering the vertical flow assays to automate the assaying steps may be expected to address the critical bottleneck facing this technology. FIGS. 10A-D show a device 520 with the integration of the cascaded fluidic diodes in a vertical flow format. The device 520 includes cascaded diode valves, cascaded with a modified diode valve as shown in FIGS. 10A-D. As the fluid is dispensed over the sorbent pads 522, 524 of individual diode valves as shown in FIG. 10B, the fluid flows into the gap 528 and gets initially pinned at the bottom inlet strip 530.

[0340] The modified diode valve portion may make it conducive for the fluid front within the gap 528 to be pinned at the bottom inlet strip 530 due to the abrupt, step like change in the channel dimension in the inlet air gap G and the gap 528. The connecting strip 534 may be hydrophilic to facilitate spreading of the fluid front along the top surface 534S until the advancing fluid front reaches the top outlet strip 532. Excess fluid pressure essentially expands the surface ofthe pinned droplet within the gap 528 until the surface of the fluid front contacts the porous nitrocellulose membrane 529 on the bottom. Upon which, the fluid flows through into the membrane 529 and gets absorbed into the absorbent pad 521.

[0341] Building on the above fluid diode technology, additional configurations may be readily produced to add further functionality to lateral flow device technology. In all of the designs, flow transitions from a capillary driven flow in paper to a surface directed flow within the parallel strips of plastic sandwiching the paper segment. Flow resistance of various degrees may be conveniently incorporated introduction of protrusions 340 within the surface directed flow channel as shown in FIGS. 5A-C and described above. FIGS. 5A-C shows the delay timer incorporating air gap valves and hydrophobic protrusions within the surface directed flow channel.

[0342] Use of protrusions 340 within the fluid diode would allow one to slow down the fluid travelling through the 328. In some embodiments, a delay time may range from a few seconds to a few minutes. For longer time delays and / or for permanent pinning of the fluid at the inlet, electronically controlled fluidic diode valves may control the time delay.

[0343] FIG. 3A shows the distance D1 between the top outlet strip 32 and the bottom inlet strip 30 permanently pins the fluid. The surface shape to change may need a large pressure difference. FIG. 3B shows increasing the distance D2 between the top outlet strip 32 and the bottom inlet strip 30 intermittently pins the fluid. The extent or size of the distance D2 determines the amount of time the fluid may be pinned at the source pad 22. The large the distance D2 may be the shorter the time the fluid may be pinned.

[0344] The electronically controlled device is shown in FIGS. 11-11C and 14 may rely on surface directed fluid flows between chemically patterned surfaces and electro wetting based surface tension control of a fluid. The device 620 may be identical to the fluidic device 20. However, this device 620 utilizes an x-y-z conductive, hydrophobic tape 630 to hold down the source pad 622 to the base strip 621 .

[0345] As previously noted, fluid applied to the source pad 622 saturates it and instantaneously flows through the gap G formed between the source pad 622 and the overlying connecting strip 634. It may be pinned in the configuration as shown in FIG. 11 B as it contacts the hydrophobic conductive strip 630 owing to an abrupt change in the contact angle of the advancing fluid.

[0346] Through controlling the extent of the hydrophobic inlet strip 630 extending beyond the source pad 622 into the gap 628, the duration of pinning may be controlled. Pinning times in excess of 60 minutes for appropriately configured devices may be achieved.

[0347] A voltage applied between the conductive adhesive inlet strip 630 and the fluid causes the surface tension of the fluid to lower and thus ‘de-pins’ the fluid to flow past the bottom inlet strip 630 and into the gap 628 encompassed by the connecting strip 634 and the base strip 621 . The hydrophilic surfaces of the connecting strip 634 and the base strip 621 within the gap 628 then exerts capillary forces on the fluid front pulling it through the gap 628 and into the drain pad 624. Thus, fluid flow within the gap 628 may be initiated through electronic control.

[0348] FIG. 13 shows another electronically controlled fluidic device 820. The device 820 encompasses a common drain pad 824 (central sorbent pad) which also forms the detection zone. The various source pads 822A-C are circularly placed as shown in FIG. 13. Each of the source pads 822A-C may hold appropriate dried reagents necessary for the performance of the assay.

[0349] The user applies the test solution directly to the detection zone 824 (as in a conventional vertical flow assay) and buffer solution to each of the source pads 822A-C prior to the commencement of the assay. The diode behavior ensures that excess test solution doesn’t flow laterally towards the source pads 822A-C.

[0350] Once plugged in, fluid flows are electronically triggered by the control logic from each of the source pads 822A-C to flow into the central detection zone 824 in a time synchronized manner by applying the appropriate voltage pulses to each of the source pads 822A-C. Excess fluid from the centraldetection zone 824 is taken away by the absorbent pad (not shown) housed directly undeneath the central pad 824 and having a fluidic connection with it.

[0351] To ensure that the fluid flow from each of the source pads 822A-C follows a single isolated path towards the common drain pad 824, the top and the bottom strips 834, 821 may be printed with wax ink defining hydrophilic channels (regions where there is no wax) connecting each of the source pads 822A-C through a single isolated channel to the common drain pad 824. Thus, despite there being no “physical barriers” separating the individual channels, isolation is still acheived through “virtual walls” formed through the hydrophobic patterning by means of surface dirceted flows.

[0352] The term water proof or water resistant means at least or about 90% of the water on the material cannot penetrate the material. In some embodiments, water proof or water resistant means at least or about 95% of the water cannot penetrate. In some embodiments, water proof or water resistant means about 100% of the water cannot penetrate.

[0353] All of the devices and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. In addition, unless expressly stated to the contrary, use of the term “a” is intended to include “at least one” or “one or more.” For example, “a device” is intended to include “at least one device” or “one or more devices.”

[0354] Any ranges given either in absolute terms or in approximate terms are intended to encompass both, and any definitions used herein are intended to be clarifying and not limiting. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood toencompass any and all subranges (including all fractional and whole values) subsumed therein.

[0355] Any device disclosed herein may comprise, consist of, or consist essentially of any element, component and / or ingredient disclosed herein or any combination of two or more of the elements, components or ingredients disclosed herein.

[0356] Any method disclosed herein may comprise, consist of, or consist essentially of any method step disclosed herein or any combination of two or more of the method steps disclosed herein.

[0357] The transitional phrase “comprising,” which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, un-recited elements, components, ingredients and / or method steps.

[0358] The transitional phrase “consisting of” excludes any element, component, ingredient, and / or method step not specified in the claim.

[0359] The transitional phrase “consisting essentially of” limits the scope of a claim to the specified elements, components, ingredients and / or steps, as well as those that do not materially affect the basic and novel characteristic(s) of the claimed invention.

[0360] As used herein, the term "about" refers to the cited value being within the errors arising from the standard deviation found in their respective testing measurements, and if those errors cannot be determined, then "about" may refer to, for example, within 5%, 4%, 3%, 2%, or 1 % of the cited value.

[0361] Furthermore, the invention encompasses any and all possible combinations of some or all of the various embodiments described herein. It should also be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

Claims

CLAIMSWhat is claimed is:1 . A fluidic diode valve, comprising: a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located in spaced apart relation from the source pad to form a gap therebetween having a predetermined width and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and a flow controller configured to control a flow of the fluid in a lateral direction from the source pad to the drain pad across the gap therebetween, the flow controller comprising: a bottom inlet strip coupled to the bottom surface of the source pad and configured to temporarily pin the flow of the fluid from the source pad into the gap, a top outlet strip coupled to the top surface of the drain pad, a bottom outlet strip coupled to the bottom surface of the drain pad, and a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end that extends over a portion of the top surface of the source pad to bridge the gap between the source pad and the drain pad so that the flow of the fluid flows in the lateral direction along a flow surface of the connecting strip when the fluid is applied to the source pad, wherein the top outlet strip and the bottom outlet strip cooperate to provide a capillary burst valve configured to prevent the fluid from flowing opposite the lateral direction back towards the source pad.

2. The fluidic diode valve of claim 1 , wherein the top outlet strip extends partway into the gap between the source pad and the drain pad.

3. The fluidic diode valve of claim 1 or claim 2, wherein the inlet end of the connecting strip is located in spaced apart relation from the source pad to form an inlet air gap therebetween.

4. The fluidic diode valve of any one of claims 1 to 3, wherein the bottom inlet strip extends partway into the gap between the source pad and the drain pad.

5. The fluidic diode valve of any one of claims 1 to 4, wherein the flow controller further comprises at least one protrusion that extends from the flow surface of the connecting strip into the gap between the source pad and the drain pad perpendicular to the flow of the fluid and the at least one protrusion configured to slow the flow of the fluid from the source pad to the drain pad, and wherein the protrusions are hydrophilic, hydrophobic, or a combination thereof.

6. The fluidic diode valve of claim 5, wherein the at least one protrusion has a predetermined height and a predetermined thickness configured to control the time delay of the flow of the fluid from the source pad to the drain pad.

7. The fluidic diode valve of any one of claims 1 to 6, wherein the flow controller further includes a plurality of protrusions spaced apart from each other along the connecting strip in the lateral direction, each protrusion extends from the flow surface of the connecting strip into the gap between the source pad and the drain pad perpendicular to the flow of fluid.

8. The fluidic diode valve of claim 7, wherein each protrusion of the plurality of protrusions is spaced apart from each other a predetermined distance configured to control the time delay of the flow of the fluid from the source pad to the drain pad.

9. The fluidic diode valve of any one of claims 1 to 8, wherein the flow controller further comprises a base strip coupled to the bottom inlet strip on the source pad and the bottom outlet strip on the drain pad so that the base strip extends between the source pad and the drain pad.

10. The fluidic diode valve of claim 9, wherein the base strip includes a base pad member configured to absorb some of the fluid as the flow of fluid flows in the lateral direction from the source pad to the drain pad.

11. The fluidic diode valve of claim 10, wherein the flow controller further include a membrane member coupled to the base pad member in the gap between the source pad and the drain pad.

12. The fluidic diode valve of any one of claims 1 to 11 , wherein the bottom inlet strip extends partway into the gap between the source pad and the drain pad.

13. The fluidic diode valve of any one of claims 1 to 12, wherein the bottom inlet strip and the top outlet strip each comprise a plastic material.

14. The fluidic diode valve of claim 13, wherein at least one of the bottom inlet strip, the bottom outlet strip, and the top outlet strip each comprise a hydrophobic plastic material.

15. The fluidic diode valve of claim 14, wherein the hydrophobic plastic material of the bottom inlet strip, the bottom outlet strip, and the top outlet strip is double-sided adhesive tape.

16. The fluidic diode valve of any one of claims 1 to 15, wherein the connecting strip comprises a plastic material.

17. The fluidic diode valve of claim 16, wherein the plastic material is hydrophilic.

18. The fluidic diode valve of claim 17, wherein the hydrophilic plastic material of the connecting strip is mylar.

19. The fluidic diode valve of claim 16, wherein the flow surface of the connecting strip is hydrophilic, hydrophobic, or a combination thereof.

20. The fluidic diode valve of claim 16, wherein the flow surface of the connecting strip is a plasma treated surface or a UV-ozone treated surface.

21. The fluidic diode valve of any one of claims 1 to 15, wherein the connecting strip comprises a water resistant cardboard material or a thick paper stock material.

22. The fluidic diode valve of any one of claims 1 to 12, wherein the bottom inlet strip of the flow controller comprises an electrically conductive material.

23. The fluidic diode valve of any one of claims 1 to 12, wherein the flow controller further includes a top inlet strip coupled to the top surface of the source pad and the top inlet strip extends partway into the gap between the source pad and the drain pad.

24. The fluidic diode valve of claim 23, wherein the flow controller further includes a base strip coupled to the bottom inlet strip on the source pad and the bottom outlet strip on the drain pad, conductive strips that each extend around one end of the base strip so that the bottom inlet strip is located between the source pad and one of the conductive strips and the bottom outlet strip is located between the drain pad and the other one of the conductive strips, and magnetic strips coupled to the bottom surface of the base strip at either end of the base strip.

25. The fluidic diode valve of claim 23, wherein the flow controller further includes a base strip coupled to the bottom inlet strip on the source pad and the bottom outlet strip on the drain pad, and wherein the base strip includes a support strip, magnetic strips coupled to a bottom surface of the support strip at either end of the support strip, and conductive strips that each extend around one end of the support strip and one magnetic strip of the magnetic strips so that the bottom inlet strip is located between the source pad and one of the conductive strips and the bottom outlet strip is located between the drain pad and the other one of the conductive strips.

26. The fluidic diode valve of any of the proceeding claims, wherein the gap between the source pad and the drain pad is open on either side of the air gap.

27. A fluidic device, comprising: a first sorbent pad configured to provide passive transportation of a fluid, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a first gap therebetween and configured to provide passive transportation of the fluid, and a first flow controller configured to control a flow of the fluid in a lateral direction from the first sorbent pad to the second sorbent pad across the first gap therebetween, the first flow controller comprising: a bottom inlet strip coupled to a bottom surface of the first sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad a top outlet strip coupled to a top surface of the second sorbent pad opposite of the bottom surface of the second sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the second sorbent pad to a second end that extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad so that the flowof the fluid flows in the lateral direction along a flow surface of the connecting strip that faces the first gap when the fluid is applied to the first sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the first sorbent pad.

28. The fluidic device of claim 27, further comprising: a third sorbent pad located in spaced apart relation from the second sorbent pad to form a second gap therebetween and configured to provide passive transportation of the fluid, and a second flow controller configured to control the flow of the fluid in the lateral direction from the second sorbent pad to the third sorbent pad across the second gap therebetween, the second flow controller comprising: an inlet strip coupled to a bottom surface of the second sorbent pad, a top outlet strip coupled to a top surface of the third sorbent pad, a bottom outlet strip coupled to a bottom surface of the third sorbent pad opposite the top surface of the third sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the third sorbent pad to a second end that extends over a portion of the top surface of the second sorbent pad to bridge the second gap between the second sorbent pad and the third sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the second sorbent pad.

29. The fluidic device of claim 28, further comprising: a fourth sorbent pad located in spaced apart relation from the third sorbent pad to form a third gap therebetween and configured to provide passive transportation of the fluid, anda third flow controller configured to control the flow of the fluid in the lateral direction from the third sorbent pad to the fourth sorbent pad across the third gap therebetween, the third flow controller comprising: a bottom inlet strip coupled to a bottom surface of the third sorbent pad, a top outlet strip coupled to a top surface of the fourth sorbent pad, a bottom outlet strip coupled to a bottom surface of the fourth sorbent pad opposite the top surface of the fourth sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the fourth sorbent pad to a second end that extends over a portion of the top surface of the third sorbent pad to bridge the third gap between the third sorbent pad and the fourth sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the third sorbent pad.

30. The fluidic device of any one of claims 27 to 29, wherein the top outlet strip extends partway into the associated gap.

31. The fluidic device of any one of claims 27 to 30, wherein the bottom inlet strips, the bottom outlet strips, and the top outlet strips of the first flow controller and the second flow controller comprise a plastic material.

32. The fluidic device of claim 31 , wherein at least one of the bottom inlet strips, the bottom outlet strips, and the top outlet strips of the first flow controller and the second flow controller comprise a hydrophobic plastic material.

33. The fluidic device of claim 32, wherein the hydrophobic plastic material of the bottom inlet strips, the bottom outlet strips, and the top outlet strips of the first flow controller and the second flow controller is double-sided adhesive tape.

34. The fluidic device of any one of claims 27 to 33, wherein the connecting strips of the first flow controller and the second flow controller comprise a plastic material.

35. The fluidic device of claim 34, wherein the plastic material is hydrophilic.

36. The fluidic device of claim 35, wherein the hydrophilic plastic material of the connecting strips of the first flow controller and the second flow controller is mylar.

37. The fluidic device of claim 36, wherein the flow surface of the connecting strip is hydrophilic, hydrophobic, or a combination thereof.

38. The fluidic device of claim 36, wherein the flow surface of the connecting strip is a plasma treated surface or a UV-ozone treated surface.

39. The fluidic diode valve of any one of claims 28 to 33, wherein the connecting strip comprises a water resistant cardboard material or a thick paper stock material.

40. The fluidic device of any one of claims 28 to 39, wherein the first end of the connecting strip of the first flow controller is located in spaced apart relation from the first sorbent pad to form an inlet air gap therebetween.

41. The fluidic device of any one of claims 28 to 40, wherein the first flow controller further comprises at least one protrusion that extends from the flow surface of the connecting strip into the first gap between the first sorbent pad and the second sorbent pad perpendicular to the flow of fluid and the at least one protrusion configured to slow the flow of fluid from the first sorbent pad to the second sorbent pad.

42. The fluidic device of claim 28, wherein the bottom inlet strip of the first flow controller comprises an electrically conductive material.

43. The fluidic device of claim 42, further comprising a power source electrically coupled to the bottom inlet strip of the first flow controller and configured to send a signal to the bottom inlet strip to cause the flow of fluid to flow into the first gap.

44. A fluidic device, comprising: a center pad configured to provide passive transportation of a fluid, a first diode valve comprising a first source pad configured to provide passive transportation of a fluid, a first drain pad coupled to the center pad so that the first drain pad is located in spaced apart relation from the first source pad to form a first gap therebetween and the first drain pad configured to provide passive transportation of the fluid, and a first flow controller configured to control a flow of fluid from the first source pad to the first drain pad across the first gap therebetween, a second diode valve comprising a second source pad configured to provide passive transportation of the fluid, a second drain pad coupled to the center pad so that the second drain pad is located in spaced apart relation from the second source pad to form a second gap therebetween and the second drain pad configured to provide passive transportation of the fluid, and a second flow controller configured to control a flow of fluid from the second source pad to the second drain pad across the second gap therebetween, and a third diode valve comprising a third source pad coupled to the center pad and configured to provide passive transportation of the fluid, a third drain pad located in spaced apart relation from the third source pad to form a third gap therebetween and configured to provide passive transportation of the fluid, and a third flow controller configured to control a flow of fluid from the third source pad to the third drain pad across the third gap therebetween, wherein each of the first flow controller, the second flow controller, and the third flow controller comprises:a bottom inlet strip coupled to a bottom surface of the associated source pad, a top outlet strip coupled to a top surface of the associated drain pad, a bottom outlet strip coupled to a bottom surface of the associated drain pad opposite the top surface of the associated drain pad, and a connecting strip that extends from a first end coupled to the top outlet strip to a second end that extends over a portion of a top surface of the associated source pad to bridge the respective gap between the associated source pad and the associated drain pad so that the flow of fluid flows from the associated source pad to the associated drain pad along a flow surface of the connecting strip that faces the associated gap when a fluid is applied to the associated source pad, and wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing back towards the associated source pad.

45. The fluidic device of claim 44, wherein the top outlet strip extends partway into the associated gap between the associated source pad and the associated drain pad.

46. The fluidic device of claim 44 or 45, wherein the bottom inlet strips of the first flow controller and the second flow controller each comprise an electrically conductive material.

47. The fluidic device of claim 46, further comprising a power source electrically coupled to the bottom inlet strips of the first flow controller and the second flow controller and configured to send a signal to the bottom inlet strips to cause the flow of fluid to flow into the associated gap.

48. The fluidic device of any one of claims 44 to 47, further comprising: a fourth diode valve comprising a fourth source pad configured to provide passive transportation of the fluid, a fourth drain pad coupled to the center padso that the fourth drain pad is located in spaced apart relation from the fourth source pad to form a fourth gap therebetween and the fourth drain pad configured to provide passive transportation of the fluid, and a fourth flow controller configured to control a flow of fluid from the fourth source pad to the fourth drain pad across the fourth gap therebetween.

49. The fluidic device of claim 48, wherein the bottom inlet strip of the fourth flow controller comprises an electrically conductive material and wherein the power source is electrically coupled to the bottom inlet strip of the fourth flow controller and configured to send the signal to the bottom inlet strip to cause the flow of fluid to flow into the associated gap.

50. A method, comprising: providing a fluidic device comprising a first sorbent pad, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a first gap therebetween, and a first flow controller comprising: an inlet strip coupled to a bottom surface of the first sorbent pad, a top outlet strip coupled to a top surface of the second sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the second sorbent pad to a second end that extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad, applying an amount of a first fluid to the first sorbent pad to cause a pressure within the first sorbent pad to exceed a capillary burst pressure to drive a portion of the amount of the first fluid from the first sorbent pad to the first end of the connecting strip of the first flow controller, transporting the first fluid in a lateral direction along a flow surface of the connecting strip of the first flow controller from the first sorbent pad to the secondsorbent pad across the first gap to saturate the second sorbent pad with the first fluid, and preventing the first fluid from flowing opposite the lateral direction back towards the first sorbent pad so that the first fluid only flows in the lateral direction from the first sorbent pad to the second sorbent pad.

51. The method of claim 50, wherein the top outlet strip of the first flow controller extends partway into the first gap between the first sorbent pad and the second sorbent pad.

52. The method of claim 50 or 51 , further comprising applying an amount of a buffer solution to the first sorbent pad and the second sorbent pad before applying the amount of the first fluid.

53. The method of any one of claims 50 to 52, wherein the first end of the connecting strip of the first flow controller is located in spaced apart relation from the first sorbent pad to form an inlet air gap therebetween, and wherein applying the amount of the first fluid to the first sorbent pad drives the first fluid across the inlet air gap between the first sorbent pad and the first end of the connecting strip of the first flow controller.

54. The method of any one of claims 50 to 53, wherein the bottom inlet strip of the first flow controller extends partway into the first gap between the first sorbent pad and the second sorbent pad, and wherein the method further comprises impeding the first fluid from flowing directly from the first sorbent pad into the first gap.

55. The method of any one of claims 50 to 54, wherein the first flow controller further comprises at least one protrusion that extends from the flow surface of the connecting strip of the first flow controller into the first gap between the first sorbent pad and the second sorbent pad perpendicular to flow surface of the connecting strip of the first flow controller and the at least one protrusionconfigured to slow the first fluid as it flows from the first sorbent pad to the second sorbent pad.

56. The method of claim 50, wherein the bottom inlet strip of the first flow controller comprises an electrically conductive material.

57. The method of claim 56, wherein the fluidic device further comprises a power source electrically coupled to the bottom inlet strip of the first flow controller, and wherein the method further comprises sending a signal from the power source to the bottom inlet strip of the first flow controller to cause the flow of fluid to flow into the first gap.

58. The method of any one of claims 50 to 57, wherein the fluidic device further comprises a third sorbent pad located in spaced apart relation from the second sorbent pad to form a second gap therebetween and a second flow controller comprising: a bottom inlet strip coupled to a bottom surface of the second sorbent pad, a top outlet strip coupled to a top surface of the third sorbent pad, a bottom outlet strip coupled to a bottom surface of the third sorbent pad opposite the top surface of the third sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the third sorbent pad to a second end that extends over a portion of the top surface of the second sorbent pad to bridge the second gap between the second sorbent pad and the third sorbent pad, and wherein the method further comprises: transporting the first fluid in the lateral direction along a flow surface of the connecting strip of the second flow controller from the second sorbent pad to the third sorbent pad across the second gap to saturate the third sorbent pad with the first fluid,preventing the first fluid from flowing opposite the lateral direction back towards the second sorbent pad so that the first fluid only flows in the lateral direction from the second sorbent pad to the third sorbent pad.

59. The method of claim 58, wherein the top outlet strip of the second flow controller extends partway into the second gap between the second sorbent pad and the third sorbent pad.

60. A method, comprising: providing a fluidic device comprising a first sorbent pad, a second sorbent pad, and a first flow controller comprising an inlet strip, a top outlet strip, a bottom outlet strip, and a connecting strip extending between a first end and a second end spaced apart laterally from the first end, arranging the second sorbent pad in spaced apart relation from the first sorbent pad to form a first gap therebetween, coupling the bottom inlet strip of the first flow controller to a bottom surface of the first sorbent pad, coupling the top outlet strip of the first flow controller to a top surface of the second sorbent pad so that a portion of the top outlet strip extends partway into the first gap between the first sorbent pad and the second sorbent pad, coupling the bottom outlet strip of the first flow controller to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, and coupling the first end of the connecting strip of the first flow controller to the top outlet strip of the first flow controller on the second sorbent pad so that the second end of the connecting strip of the first flow controller extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad.

61. The method of claim 60, further comprising applying an amount of a first fluid to the first sorbent pad to cause the first fluid to flow in a lateral directionalong a flow surface of the connecting strip from the first sorbent pad to the second sorbent pad.

62. The method of claim 61 , further comprising applying an amount of a buffer solution to the first sorbent pad and the second sorbent pad before applying the amount of the first fluid.

63. The method of any one of claims 60 to 62, wherein the fluidic device further comprises a third sorbent pad and a second flow controller comprising an inlet strip, a top outlet strip, a bottom outlet strip, and a connecting strip extending between a first end and a second end spaced apart laterally from the first end, wherein the method further comprises arranging the third sorbent pad in spaced apart relation from the second sorbent pad to form a second gap therebetween, coupling the bottom inlet strip of the second flow controller to a bottom surface of the second sorbent pad, coupling the top outlet strip of the second flow controller to a top surface of the third sorbent pad so that a portion of the top outlet strip of the second flow controller extends partway into the first gap between the first sorbent pad and the second sorbent pad, coupling the bottom outlet strip of the second flow controller to a bottom surface of the third sorbent pad opposite the top surface of the third sorbent pad, and coupling the first end of the connecting strip of the second flow controller to the top outlet strip of the second flow controller on the third sorbent pad so that the second end of the connecting strip of the second flow controller extends over a portion of the top surface of the second sorbent pad to bridge the first gap between the second sorbent pad and the third sorbent pad.

64. The method of any one of claims 60 to 63, wherein the second end of the connecting strip of the first flow controller is located in spaced apart relation from the first sorbent pad to form an inlet air gap therebetween.

65. The method of any one of claims 60 to 64, wherein the first flow controller further comprises at least one protrusion that extends from the flow surface of the connecting strip of the first flow controller into the first gap between the first sorbent pad and the second sorbent pad perpendicular to the flow surface of the connecting strip of the first flow controller and the at least one protrusion configured to slow the flow of fluid from the first sorbent pad to the second sorbent pad.

66. A fluidic diode device, comprising: a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located in spaced apart relation from the source pad to form a gap therebetween having a predetermined width and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and a flow controller arranged to extend between the source pad and the drain pad and configured to control a flow of the fluid in a lateral direction from the source pad to the drain pad across the gap therebetween by allowing the flow of fluid to flow in the lateral direction in response to a signal from a power source coupled to the fluidic diode device.

67. The fluidic diode device of claim 66, wherein the flow controller includes conducting electrodes, the power source is coupled to the electrodes, and the signal from the power source is a potential applied across the electrodes.

68. The fluidic diode device of claim 66 or 67, wherein the flow controller comprises: a base strip extending between a first end near the source pad and a second end spaced apart laterally from the first end near the drain pad, the base strip including a first layer of magnetic material and a second layer of plastic material coupled to the first layer, inlet and outlet metallized films each arranged to extend around one of the first end and the second end of the base strip and partially along the base strip, top and bottom inlet strips each coupled to one of the top surface and the bottom surface of the source pad, the bottom inlet strip coupled to the inlet metallized film, top and bottom outlet strips each coupled to one of the top surface and the bottom surface of the drain pad, the bottom outlet strip coupled to the outlet metallized film, a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end coupled to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad, and a ledger strip coupled to the base strip in the gap between the source pad and the drain pad, wherein the outlet metallized film extends over the ledge strip.

69. The fluidic diode device of claim 66 or 67, wherein the flow controller comprises: top and bottom inlet strips each coupled to one of the top surface and the bottom surface of the source pad, top and bottom outlet strips each coupled to one of the top surface and the bottom surface of the drain pad, a base strip that extends from a first end coupled to the bottom outlet strip on the drain pad to a second end coupled to the bottom inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a bottom side of the gap, the base strip comprising: a magnetic strip,a support strip coupled to the magnetic strip, inlet and outlet metallized films each arranged to extend around and partially along the magnetic strip and the support strip on the first end and the second end of the base strip, a ledge strip coupled to the support strip in the gap between the source pad and the drain pad, wherein the outlet metallized film extends over the ledge strip, and a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end coupled to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad.

70. The fluidic diode device of claim 68 or 69, wherein the top inlet strip and the ledge strip cooperate to provide a burst valve, and wherein the burst valve is compromised in response to the signal from the power source to allow the flow of fluid to flow in the lateral direction.71 . The fluidic diode device any one of claims 68 to 70, wherein the top and bottom inlet strips, the top and bottom outlet strips, and the ledge strip are double-sided adhesive tape.

72. The fluidic diode device of any one of claims 68 to 71 , wherein the plastic material is mylar.

73. The fluidic diode device of any one of claims 68 to 72, wherein the inlet and outlet metallized films each comprise one of copper, aluminum, platinum, silver, palladium, and / or any other suitable conductive material.

74. The fluidic diode device of any one of clams 68 to 72, wherein the inlet and outlet metallized films each have a dielectric film comprising a selfassembled monolayer or an atomic layer deposited film.

75. A device, comprising:a power source, a printed circuit board electrically coupled to the power source, and a fluidic diode device integrated with the printed circuit board, the fluidic diode device comprising: a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located in spaced apart relation from the source pad to form a gap therebetween having a predetermined width and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and a flow controller arranged to extend between the source pad and the drain pad and configured to control a flow of the fluid in a lateral direction from the source pad to the drain pad across the gap therebetween by allowing the flow of fluid to flow in the lateral direction in response to a signal from the power source through the printed circuit board.

76. The device of claim 75, further comprising at least one lighting element coupled to the printed circuit board and configured to send a light signal in response to the signal from the power source.

77. The device of claim 75 or 76, wherein the flow controller further comprises conducting electrodes that engage conduct pads on the printed circuit board and the signal from the power source is a potential applied across the electrodes.

78. The device of any one of claims 75 to 77, wherein the flow controller comprises: a base strip extending between a first end near the source pad and a second end spaced apart laterally from the first end near the drain pad, the basestrip including a first layer of magnetic material and a second layer of plastic material coupled to the first layer, inlet and outlet metallized films each arranged to extend around one of the first end and the second end of the base strip and partially along the base strip, top and bottom inlet strips each coupled to one of the top surface and the bottom surface of the source pad, the bottom inlet strip coupled to the inlet metallized film, top and bottom outlet strips each coupled to one of the top surface and the bottom surface of the drain pad, the bottom outlet strip coupled to the outlet metallized film, a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end coupled to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad, and a ledge strip coupled to the base strip in the gap between the source pad and the drain pad, wherein the outlet metallized film extends over the ledge strip.

79. The device of any one of claims 75 to 77, wherein the flow controller comprises: top and bottom inlet strips each coupled to one of the top surface and the bottom surface of the source pad, top and bottom outlet strips each coupled to one of the top surface and the bottom surface of the drain pad, a base strip that extends from a first end coupled to the bottom outlet strip on the drain pad to a second end coupled to the bottom inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a bottom side of the gap, the base strip comprising: a magnetic strip, a support strip coupled to the magnetic strip, inlet and outlet metallized films each arranged to extend around and partially along the magnetic strip and the support strip on the first end and the second end of the base strip,a ledge strip coupled to the support strip in the gap between the source pad and the drain pad, wherein the outlet metallized film extends over the ledge strip, and a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end coupled to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad.

80. The device of claim 78 or 79, wherein the top inlet strip and the ledge strip cooperate to provide a burst valve, and wherein the burst valve is compromised in response to the signal from the power source to allow the flow of fluid to flow in the lateral direction.

81. The device of any one of claims 78 to 80 , wherein the top and bottom inlet strips, the top and bottom outlet strips, and the ledge strip are double-sided adhesive tape.

82. The device of any one of claims 78 to 81 , wherein the plastic material is mylar.

83. The device of any one of claims 78 to 82, wherein the inlet and outlet metallized films each comprise one of copper, aluminum, silver, platinum, palladium, and / or any other suitable conductive material.

84. The fluidic diode device of any one of clams 78 to 82, wherein the inlet and outlet metallized films each have a dielectric film comprising a selfassembled monolayer or an atomic layer deposited film.

85. A method, comprising: providing a fluidic device comprising a source pad, a drain pad located in spaced apart relation from the source pad to form a gap therebetween, and a flow controller arranged to extend between the source pad and the drain pad, providing a power source electrically coupled to the flow controller,applying an amount of a fluid to the source pad that gets pinned at the source pad, sending a signal from the power source to the flow controller to de-pin the fluid to allow the flow of fluid to flow into the first gap, transporting the first fluid in a lateral direction from the source pad to the drain pad across the first gap to saturate the drain pad with the fluid, and preventing the fluid from flowing opposite the lateral direction back towards the source pad so that the first fluid only flows in the lateral direction from the source pad to the drain pad.

86. A fluidic diode valve, comprising: a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located in spaced apart relation to the source pad to form a gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and flow control means for transporting a flow of the fluid applied to the source pad in a lateral direction from the source pad to the drain pad across the gap therebetween to saturate the drain pad with the fluid while preventing the fluid from flowing opposite the lateral direction back towards the source pad so that the fluid only flows in the lateral direction from the source pad to the drain pad.

87. The fluidic diode valve of claim 86, wherein the flow control means comprises: a bottom inlet strip coupled to the bottom surface of the source pad, a top outlet strip coupled to the top surface of the drain pad, a bottom outlet strip coupled to the bottom surface of the drain pad,a base strip that extends from the bottom outlet strip on the drain pad to the bottom inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a bottom side of the gap, and a connecting strip that extends from the top outlet strip on the drain pad to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a top side of the gap so that the flow of the fluid flows in the lateral direction across the gap when the fluid is applied to the source pad, wherein the top and bottom outlets strips are at least flush with an outer edge of the drain pad and cooperate to provide a burst valve configured to prevent the flow of the fluid from flowing opposite the lateral direction back towards the source pad.

88. The fluidic diode valve of claim 87, wherein the inlet end of the connecting strip is located in spaced apart relation from the source pad to form an inlet air gap therebetween.

89. The fluidic diode valve of any one of claims 87 to 88, wherein the flow control means further comprises a top inlet strip coupled to the top surface of the source pad.

90. The fluidic diode valve of claim 89, wherein the top inlet strip extends partway into the gap between the source pad and the drain pad.

91. The fluidic diode valve of any one of claims 87 to 90, wherein the bottom inlet strip extends partway into the gap between the source pad and the drain pad.

92. The fluidic diode valve of any one of claims 87 to 91 , wherein the top and bottom outlet strips do not extend past the outer edge of the drain pad into the gap.

93. The fluidic diode valve of any one of claims 87 to 91 , wherein the top outlet strip extends partway into the gap between the source pad and the drain pad.

94. The fluidic diode valve of any one of claims 87 to 93, wherein the flow control means further comprises at least one protrusion that extends from the connecting strip into the gap between the source pad and the drain pad perpendicular to the flow of the fluid and the at least one protrusion configured to slow the flow of the fluid from the source pad to the drain pad, and wherein the protrusions are hydrophilic, hydrophobic, or a combination thereof.

95. The fluidic diode valve of claim 94, wherein the at least one protrusion has a predetermined height and a predetermined thickness configured to control the time delay of the flow of the fluid from the source pad to the drain pad.

96. The fluidic diode valve of any one of claims 87 to 93, wherein the flow control means further includes a plurality of protrusions spaced apart from each other along the connecting strip in the lateral direction, each protrusion extends from a flow surface of the connecting strip into the gap between the source pad and the drain pad perpendicular to the flow of fluid.

97. The fluidic diode valve of claim 96, wherein each protrusion of the plurality of protrusions is spaced apart from each other a predetermined distance configured to control the time delay of the flow of the fluid from the source pad to the drain pad.

98. The fluidic diode valve of any one of claims 87 to 97, wherein the bottom inlet strip and the top outlet strip each comprise a plastic material.

99. The fluidic diode valve of claim 98, wherein at least one of the bottom inlet strip, the bottom outlet strip, and the top outlet strip each comprise a hydrophobic plastic material.

100. The fluidic diode valve of claim 99, wherein the hydrophobic plastic material of the bottom inlet strip, the bottom outlet strip, and the top outlet strip is double-sided adhesive tape.101 . The fluidic diode valve of any one of claims 87 to 100, wherein the base strip and the connecting strip each comprises a plastic material.

102. The fluidic diode valve of 101 , wherein the plastic material is hydrophilic.

103. The fluidic diode valve of claim 102, wherein the hydrophilic plastic material is mylar.

104. The fluidic diode valve of any one of claims 87 to 100, wherein the connecting strip comprises a water resistant cardboard material or a thick paper stock material.

105. The fluidic diode valve of any one of claims 87 to 100, wherein the connecting strip defines a flow surface that faces the gap and the flow surface of the connecting strip is hydrophilic, hydrophobic, or a combination thereof.

106. The fluidic diode valve of any one of claims 87 to 100, wherein the flow surface of the connecting strip is a plasma treated surface or a UV-ozone treated surface.

107. The fluidic diode valve of any one of claims 87 to 97, wherein the base strip comprises: a magnetic strip, a support strip coupled to the magnetic strip, inlet and outlet metallized films each arranged to extend around and partially along the magnetic strip and the support strip on the first end and the second end of the base strip, anda ledge strip coupled to the support strip in the gap between the source pad and the drain pad, wherein the outlet metallized film extends over the ledge strip.

108. The fluidic diode valve of any one of claims 87 to 107, wherein the gap between the source pad and the drain pad is open on either side of the air gap.

109. A device, comprising: the fluidic diode valve of claim 98, and a power source electrically coupled to the fluidic diode valve and configured to send a signal to the fluidic diode valve to allow the flow of fluid to flow into the gap.

110. The device of claim 109, wherein the fluidic diode valve is integrated with a lateral flow assay sample pad.

111. The device of claim 110, wherein the fluidic diode valve interfaces the lateral flow sample pad at a right angle.

112. The device of claim 111 , wherein the drain pad of the fluidic diode valve is between the source pad and the lateral flow assay sample pad.

113. The device of claim 111 , wherein the source pad of the fluidic diode valve is between the drain pad and the lateral flow assay sample pad.

114. A lateral flow assay device comprising the fluidic diode valve of claim 86.

115. The lateral flow assay device of claim 114, comprising a lateral flow sample pad, and wherein the fluidic diode valve interfaces the lateral flow sample pad at a right angle.

116. The device of claim 115, wherein the drain pad of the fluidic diode valve is between the source pad and the lateral flow assay sample pad.

117. The device of claim 116, wherein the source pad of the fluidic diode valve is between the drain pad and the lateral flow assay sample pad.

118. A vertical flow assay device comprising the fluidic diode valve of claim 86.

119. A fluidic device, comprising: a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a drain pad located in spaced apart relation to the source pad to form a gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the drain pad, and a flow controller configured to control a flow of the fluid in only a lateral direction from the source pad to the drain pad across the gap therebetween.

120. The device of claim 119, wherein the flow controller comprises: a bottom inlet strip coupled to the bottom surface of the source pad, a top outlet strip coupled to the top surface of the drain pad, a bottom outlet strip coupled to the bottom surface of the drain pad, a base strip that extends from the bottom outlet strip on the drain pad to the bottom inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a bottom side of the gap, and a connecting strip that extends from the top outlet strip on the drain pad to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a top side of the gap so that the flow of the fluid flows in the lateral direction across the gap when the fluid is applied to the source pad,wherein the top and bottom outlets strips are at least flush with an outer edge of the drain pad and cooperate to prevent the flow of the fluid from flowing opposite the lateral direction back towards the source pad.

121. A method, comprising: providing a fluidic device comprising a first sorbent pad, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a gap therebetween, and a flow controller comprising: an inlet strip coupled to a bottom surface of the first sorbent pad, a top outlet strip coupled to a top surface of the second sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad opposite the top surface of the second sorbent pad, a base strip that extends from a first end coupled to the bottom outlet strip on the second sorbent pad to a second end coupled to the bottom inlet strip on the first sorbent pad to bridge the gap between the first and second sorbent pads on a bottom side of the gap, and a connecting strip that extends from a first end coupled to the top outlet strip on the second sorbent pad to a second end that extends over a portion of the top surface of the first sorbent pad to bridge the first gap between the first sorbent pad and the second sorbent pad on a top side of the gap, applying an amount of a fluid to the first sorbent pad to cause a pressure within the first sorbent pad to exceed a capillary burst pressure to drive a portion of the amount of the first fluid from the first sorbent pad into the gap, transporting the first fluid in a lateral direction along a flow surface of the connecting strip and a flow surface of the base strip of the flow controller from the first sorbent pad to the second sorbent pad across the gap to saturate the second sorbent pad with the fluid, and preventing the first fluid from flowing opposite the lateral direction back towards the first sorbent pad so that the first fluid only flows in the lateral direction from the first sorbent pad to the second sorbent pad.

122. A fluidic device, comprising: a first sorbent pad configured to provide passive transportation of a fluid, a second sorbent pad located in spaced apart relation from the first sorbent pad to form a first gap therebetween and configured to provide passive transportation of the fluid, and a first flow controller configured to control a flow of the fluid in only a lateral direction from the first sorbent pad to the second sorbent pad across the first gap therebetween.

123. The fluidic device of claim 122, wherein the first flow controller comprises: a bottom inlet strip coupled to a bottom surface of the first sorbent pad, a bottom outlet strip coupled to a bottom surface of the second sorbent pad a top outlet strip coupled to a top surface of the second sorbent pad opposite of the bottom surface of the second sorbent pad, a base strip that extends from the bottom outlet strip on the second sorbent pad to the bottom inlet strip on the first sorbent pad to bridge the gap between the first sorbent pad and the second sorbent pad on a bottom side of the first gap, and a connecting strip that extends from the top outlet strip on the second sorbent pad to the top inlet strip on the first sorbent pad to bridge the gap between the first sorbent pad and the second sorbent pad on a top side of the first gap so that the flow of the fluid flows in the lateral direction across the gap when the fluid is applied to the first sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the first sorbent pad.

124. The fluidic device of claim 122 or 123, further comprising:a third sorbent pad located in spaced apart relation from the second sorbent pad to form a second gap therebetween and configured to provide passive transportation of the fluid, and a second flow controller configured to control the flow of the fluid in only the lateral direction from the second sorbent pad to the third sorbent pad across the second gap therebetween.

125. The fluidic device of claim 124, wherein the second flow controller comprises:an inlet strip coupled to a bottom surface of the second sorbent pad, a top outlet strip coupled to a top surface of the third sorbent pad, a bottom outlet strip coupled to a bottom surface of the third sorbent pad opposite the top surface of the third sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the third sorbent pad to a second end that extends over a portion of the top surface of the second sorbent pad to bridge the second gap between the second sorbent pad and the third sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the second sorbent pad.

126. The fluidic device of claim 125, wherein the base strip extends from the bottom outlet strip on the third sorbent pad to the bottom inlet strip on the first sorbent pad to bridge the first and second gaps.

127. The fluidic device of claim 126, further comprising: a fourth sorbent pad located in spaced apart relation from the third sorbent pad to form a third gap therebetween and configured to provide passive transportation of the fluid, and a third flow controller configured to control the flow of the fluid in only the lateral direction from the third sorbent pad to the fourth sorbent pad across the third gap therebetween.

128. The fluidic device of claim 127, wherein the third flow controller comprises: a bottom inlet strip coupled to a bottom surface of the third sorbent pad, a top outlet strip coupled to a top surface of the fourth sorbent pad, a bottom outlet strip coupled to a bottom surface of the fourth sorbent pad opposite the top surface of the fourth sorbent pad, and a connecting strip that extends from a first end coupled to the top outlet strip on the fourth sorbent pad to a second end that extends over a portion of the top surface of the third sorbent pad to bridge the third gap between the third sorbent pad and the fourth sorbent pad, wherein the top outlet strip cooperates with the bottom outlet strip to prevent the fluid from flowing opposite the lateral direction back towards the third sorbent pad.

129. The fluidic device of claim 128, wherein the base strip extends from the bottom outlet strip on the fourth sorbent pad to the bottom inlet strip on the first sorbent pad to bridge the first, second, and third gaps.

130. A fluidic device, comprising: a source pad comprising a paper material configured to provide passive transportation of a fluid, the source pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the source pad, a conjugate pad located in spaced apart relation to the source pad to form a first gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the conjugate pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the conjugate pad, a drain pad located in spaced apart relation to the conjugate pad to form a second gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the drain pad having a top surface and abottom surface spaced apart from the top surface to define a thickness of the drain pad, an absorbent pad located in spaced apart relation to the drain pad to form a third gap therebetween, a flow controller configured to control a flow of the fluid in only a lateral direction from the source pad to the conjugate pad across the first gap therebetween, from the conjugate pad to the drain pad across the second gap therebetween, and from the drain pad to the absorbent pad across the third gap therebetween.131 . The device of claim 130, wherein the flow controller comprises: top and bottom inlet strips coupled to the top and bottom surfaces of the source pad, top and bottom intermediate strips coupled to the top and bottom surfaces of the conjugate pad, top and bottom outlet strips coupled to the top and bottom surfaces of the drain pad, a base strip that extends from a first end coupled to the absorbent pad to a second end coupled to the bottom inlet strip on the source pad to bridge the first, second, and third gaps on a bottom side of the first, second, and third gaps, a connecting strip that extends from an outlet end coupled to the top outlet strip on the drain pad to an inlet end coupled to the top inlet strip on the source pad to bridge the gap between the source pad and the drain pad on a top side of the gap, and a membrane member coupled to the base strip that extends between the drain pad and the absorbent pad to bridge the third gap.

132. The device of claim 131 , wherein the top and bottom outlets strips are at least flush with an outer edge of the drain pad to provide a burst valve configured to prevent the flow of the fluid from flowing opposite the lateral direction back towards the conjugate pad.

133. The device of claim 131 or 132, wherein the top and bottom intermediate strips are at least flush with an outer edge of the conjugate pad to provide a another burst valve configured to prevent the flow of the fluid from flowing opposite the lateral direction back towards the source pad.

134. The device of any one of claims 130 to 133, further comprising a filter located vertically above the drain pad and a vertical flow controller arranged between the filter and the drain pad to control a flow in a vertical direction from the filter to the drain pad across a vertical gap therebetween to prevent the fluid from flowing opposite the vertical direction from the drain pad back towards the filter.

135. A device, comprising: a paper based device comprising a sample pad, and a fluidic diode valve comprising: a first sorbent pad comprising a paper material configured to provide passive transportation of a fluid, the first sorbent pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the first sorbent pad, a second sorbent pad located in spaced apart relation to the first sorbent pad to form a first gap therebetween and comprising paper material configured to provide passive transportation of the fluid, the second sorbent pad having a top surface and a bottom surface spaced apart from the top surface to define a thickness of the second sorbent pad, and a flow controller configured to control a flow of the fluid in only a lateral direction from the source pad to the drain pad across the first gap therebetween, wherein the fluidic diode valve is integrated with the sample pad of the paper based device so that the flow controller is configured to control the flow of fluid to the sample pad of the paper based device from the drain pad or from the sample pad of the paper based device to the source pad.

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