Devices and methods for blood analysis using electrochemistry electrodes

Abstract

Disclosed herein are methods and devices for sample analysis. There is provided a movement grid comprising a top layer and a bottom layer, the bottom layer comprising a dielectric layer coated with a bottom hydrophobic layer, the top layer comprising a conductive top plate coated with a top hydrophobic layer, the top layer and the bottom layer defining a cavity, wherein a plurality of digital microfluidic (DMF) electrodes are configured to selectively actuate regions of the dielectric layer to move a sample droplet within the cavity between regions corresponding to each of the plurality of DMF electrodes via electrowetting-on-dielectric forces; and at least one sensor configured to measure the sample droplet. The methods and / or devices move the sample droplet through the movement grid and to the at least one sensor.

Description

DEVICES AND METHODS FOR BLOOD ANALYSIS USING ELECTROCHEMISTRY ELECTRODESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims all benefit including priority to U.S. Provisional Patent Application 63 / 552,409, filed February 12, 2024, and entitled “DEVICES AND METHODS FOR BLOOD ANALYSIS USING ELECTROCHEMISTRY ELECTRODES”, the entire contents of which are hereby incorporated by reference herein.TECHNICAL FIELD

[0002] The disclosure relates generally to biological analytics, and more particularly to systems and methods for blood plasma analysis.BACKGROUND

[0003] Blood tests are an invaluable tool in the field of healthcare and research. They can be instrumental in determining physiological and biological states. For example, they can be used to detect specific components of blood (e.g., glucose, cholesterol, etc.). These blood tests often necessitate blood collection and subsequent processing (if needed) to render quantitative or qualitative analytes.

[0004] Despite the ubiquity of blood tests, they can still prove to be challenging to implement in, for example, an at-home setting without a healthcare practitioner. Furthermore, current methods of conducting complex blood tests (e.g., ones with specific methodologies to produce the relevant analyte) may still leave room for human error. High volumes of sample may make it more challenging to conduct the necessary analysis because the subject may not have sufficient blood to give or may not want to give that much blood. Such considerations can limit the accuracy and / or types of blood tests that can be conducted off of a single collection sample.

[0005] Improvements in the field of blood tests are desirable.SUMMARY

[0006] In one aspect, there is provided a device for sample analysis. The device includes a movement grid comprising a top layer and a bottom layer, the bottom layer comprising a dielectric layer coated with a bottom hydrophobic layer, the top layer comprising a conductive top platecoated with a top hydrophobic layer, the top layer and the bottom layer defining a cavity, wherein a plurality of digital microfluidic (DMF) electrodes are configured to selectively actuate regions of the dielectric layer to move a sample droplet within the cavity between regions corresponding to each of the plurality of DMF electrodes via electrowetting-on-dielectric forces; at least one sensor configured to measure the sample droplet; and a bridge extending between at least one of the DMF electrodes and the at least one sensor to facilitate movement of the sample droplet to the at least one sensor. The device is configured to move the sample droplet through the movement grid and from the movement grid to the at least one sensor via the bridge.

[0007] In some embodiments, the bridge includes a hydrophilic coating applied to at least part of the at least one of the DMF electrodes and at least part of the at least one sensor.

[0008] In some embodiments, the bridge includes a hydrophilic polymer matrix or surfactant. In some embodiments, the bridge includes a membrane formed of a dried hydrogel.

[0009] In some embodiments, the bridge forms a hydrophilic surface above at least a portion of the movement grid.

[0010] In another aspect, there is provided a device for sample analysis. The device includes a movement grid comprising a top layer and a bottom layer, the bottom layer comprising a dielectric layer coated with a bottom hydrophobic layer, the top layer comprising a conductive top plate coated with a top hydrophobic layer, the top layer and the bottom layer defining a cavity, wherein a plurality of digital microfluidic (DMF) electrodes are configured to selectively actuate regions of the dielectric layer to move a sample droplet within the cavity between regions corresponding to each of the plurality of DMF electrodes via electrowetting-on-dielectric forces; and at least one sensor configured to measure the sample droplet. The device is configured to move the sample droplet through the movement grid and to the at least one sensor.

[0011] In some embodiments, the movement grid is disposed on a printed circuit board and the at least one sensor is disposed in a cavity of the printed circuit board.

[0012] In some embodiments, the at least one sensor is disposed on a printed circuit board and the at least one sensor includes an electrode with a via-in-pad.

[0013] In some embodiments, the at least one sensor includes an electrode pad and a wire extending from a first location on the electrode pad to a second location on the electrode pad to form a loop.

[0014] In some embodiments, the wire is wire-bonded to the electrode pad.

[0015] In some embodiments, the wire is formed of gold.

[0016] In some embodiments, the device further includes a controller to detect an unexpected increase in a signal from the at least one sensor.

[0017] In some embodiments, the unexpected increase is an unexpected increase in measured current.

[0018] In some embodiments, the controller is configured to generate an alert based on the signal.

[0019] In some embodiments, the controller is configured to deactivate the at least one sensor based on the signal.

[0020] In some embodiments, the device further includes a controller to schedule timing of activation of the at least one sensor based on timing of activations of the DMF electrodes.

[0021] In some embodiments, the controller schedules timing of activation of the at least one sensor to be interleaved with timing of activations of the DMF electrodes.

[0022] In some embodiments, the device further includes a controller to monitor movement of a sample droplet from the movement grid to the at least one sensor.

[0023] In some embodiments, the controller performs at least one pilot assay prior to a primary assay.

[0024] In some embodiments, the controller causes the at least one sensor to activate in a first voltage range for the at least one pilot assay and to activate in a second voltage range higher than the first voltage range for the primary assay.

[0025] In some embodiments, the controller causes the at least one sensor to activate in a first voltage range for the at least one pilot assay and to activate in a second voltage range lower than the first voltage range for the primary assay.

[0026] In some embodiments, the at least one sensor includes a plurality of wires suspended over a given one of the DMF electrodes, each of the wires functioning as an electrode of the at least one sensor.

[0027] In some embodiments, the device is configured to move a droplet away from the given one of the DMF electrodes.

[0028] Embodiments may include combinations of the above features.

[0029] Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description included below and the drawings.DESCRIPTION OF THE DRAWINGS

[0030] Reference is now made to the accompanying drawings, in which:

[0031] FIG. 1 is a system diagram of an at-home health monitor system, according to some embodiments.

[0032] FIG. 2 is a system diagram of an embodiment analyzer system, according to some embodiments.

[0033] FIG. 3A is a top view of an embodiment analyzer system, according to some embodiments.

[0034] FIG. 3B is a perspective view of an embodiment analyzer system, according to some embodiments.

[0035] FIG. 3C is a side view of an embodiment analyzer system, according to some embodiments.

[0036] FIG. 4 is a perspective view of a chip with digital microfluidic components, according to some embodiments.

[0037] FIG. 5A is a plan view of a chip, according to some embodiments.

[0038] FIG. 5B is a plan view of a chip with a virtual bulk fluid reservoir, according to some embodiments.

[0039] FIG. 6 is a top view of digital microfluidic electrodes with droplets contained thereon, according to some embodiments.

[0040] FIG. 7A is a cross-sectional elevation view of a chip, according to some embodiments.

[0041] FIG. 7B is a cross-sectional elevation view of a chip, according to some embodiments.

[0042] FIG. 8 is a plan view of a chip with reagents provided thereon, according to some embodiments.

[0043] FIG. 9A is a cross-sectional elevation view of a single electrochemical sensor, according to some embodiments.

[0044] FIG. 9B is a cross-sectional elevation view of a multilayer electrochemical sensor, according to some embodiments.

[0045] FIG. 9C is a perspective view of an electrochemical sensor with reagents provided thereon, according to some embodiments.

[0046] FIG. 10A is a plan view of an electrochemical sensor, according to some embodiments.

[0047] FIG. 10B is a plan view of an electrochemical sensor with a split counter electrode arrangement, according to some embodiments.

[0048] FIG. 10C is a plan view of an electrochemical sensor with carbon nano-tubes, according to some embodiments.

[0049] FIG. 11A illustrates a bridge for moving a droplet from the movement grid to an electrochemical sensor, according to some embodiments.

[0050] FIG. 11 B illustrates the movement grid and an electrochemical sensor, according to some embodiments.

[0051] FIG. 12A and FIG. 12B each is a top view of an electrode, according to some embodiments.

[0052] FIG. 13 is an elevation view of an electrode, according to some embodiments.

[0053] FIG. 14 is a cross-sectional elevation view of an electrochemical sensor, according to some embodiments.

[0054] FIG. 15 is an elevation view of an electrochemical sensor, according to some embodiments.

[0055] FIG. 16 is a schematic diagram of a computing device, according to some embodiments.DETAILED DESCRIPTION

[0056] Before any embodiments are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the accompanying drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.

[0057] The improvements described herein are generally directed to systems and methods for improved health monitoring hardware and software. The improvements described herein can be used to make at-home health monitoring and blood tests more reliable and robust. In particular, the improvements described herein can be used in systems designed for chip- or cartridge-based analyte tests (e.g., blood or blood plasma) carried out using a testing platform such as an analyzer system.

[0058] Such chip-based testing systems can comprise a sample collection system, an (optionally disposable) chip, and an analyzer system. The sample collection system can be used to collect a sample (e.g., blood plasma) from the subject. The sample may then be provided to the chip housed in the system analyzer. The chip may be configured with various components toanalyze the sample which may be operated by the system analyzer. Separation of chip and system analyzer may permit the use of multiple chips (e.g., to carry out different analyses or to minimize contamination between samples). The system may further involve the use of general and / or specialty software embedded within the analyzer, on an app, and / or carried out by cloud computing. When operated, the chip-based system may be capable of carrying out analyses on the sample. Such analysis may be used to diagnose a subject of a condition, monitor various biological metrics or other metrics, or carry out other objectives.

[0059] The sample collection system can be configured to collect a sample (e.g., blood) from the subject. The sample collection system can be configured to carry out specific operations with the sample prior to providing the sample to the chip. For example, the sample collection system may be configured to filter the sample. As a further example, the sample collection system may be configured to carry out plasma separation for blood samples. The sample collection system may further be configured with an adaptor to aid in the provision of the sample to the chip after collection. Such adaptors can ensure that a consistent delivery of sample to the chip which may limit contamination of the sample by external contaminants or ensure that the sample is delivered in a manner to ensure it will be usable by the chip.

[0060] Aspects of various embodiments are described through reference to the drawings.

[0061] FIG. 1 is a system diagram of an at-home health monitor system 10, according to some embodiments.

[0062] The system 10 can include a chip 100, a user device 200, and an analyzer system 300. The system components can work together to execute a test on a sample collected using the sample collection system described above. For example, a user may be able to detect the type of the chip 100 (e.g., the type of test executable by the chip or the configuration of the tests on the chip 100). The user may be able to detect this from the chip 100, for example, by scanning a barcode, QR code, RFID tag (e.g., NFC), or EEPROM on the chip using the user device 200. Alternatively, the user may be asked to input a code on the chip 100 into the user device 200. The user may then place the chip 100 or otherwise insert the chip 100 into the analyzer system 300. The user device 200 may then select or otherwise determine the microfluidic operations sequences from the chip type of chip 100 and transmit the microfluidic operations sequence to the analyzer system 300 to carry out the testing on a sample. The analyzer system 300 may be configured to transmit the test results back to the user device 200.

[0063] In some embodiments, the user device 200 may include a processor 202, a memory 204, an I / O interface 206, and a network interface 208. The user device may be configured to detect or receive a chip type (e.g., a chip ID) from the chip 100 by, for example, scanning with the user device 200 or input by the user (e.g., by the I / O interface 206). In alternative embodiments, the chip type may be detected by the analyzer system 300 when the chip 100 is therein inserted and this information may be transmitted to the user device 200 using the network interface 208. The user device 200 determines the microfluidic operations sequence based on the chip type. The user device 200 may pull the operations from the memory 204 or it may communicate with an external server (not shown) to pull the operations. The user device 200 may transmit these instructions to the analyzer system 300 using the network interface 208. While or after carrying out the microfluidic operations sequence, the analyzer system 300 may transmit per-channel raw electrochemical data (or error data as the case may be) to the user device 200. The user device 200 may be configured to process the data received from the analyzer system 300 and provide the user (or another third party) with results of the test.

[0064] In some embodiments, the analyzer system 300 may be configured to carry out instructions received by the user device 200 and provide results from the sensors to the user device 200. In some embodiments, the analyzer system 300 may be configured to carry out some processing operations onboard its own system (e.g., microfluidic operations sequence processing, basic fault-tolerance operations, some analytical processing, etc.). It is to be understood that the processes described herein as occurring on the user device 200 or the analyzer system 300 may equally be carried out by or in conjunction with the opposite component.

[0065] In some embodiments, the user device 200 may be configured to transmit and receive information from an external server (not shown). This may be used to upload test results data from the user device 200 or download software updates onto the user device 200. In some embodiments, the user device 200 may be configured to transmit software updates to the analyzer system 300. In some embodiments, the analyzer system 300 may be configured to communicate directly with an external server.

[0066] The processor 202 may include an app 210 configured to execute operations related to testing and orchestrating the functionality described herein. The processor 202 may include details and variations as described below with reference to the processor 1602 of FIG. 16 below.

[0067] The app 210 may be configured to receive the chip type (e.g., by scanning the chip 100, by user input, or through information received from the analyzer system 300), instruct the analyzer system 300 to carry out a test by transmitting microfluidic operations sequences, receive information (e.g., per-channel electrochemical data) from the analyzer system 300, and present the results to the user. The app 210 may further be configured to receive updates from an external server and (where appropriate) push those to the analyzer system 300.

[0068] The memory 204 may be configured to store information related to the operation of the system. For example, the memory 204 may store microfluidic operations sequences associated with a plurality of chip types. The memory 204 may further store information related to a user profile which may be used to present data to a user with their preferences therein input, or with historical results presented therein. The memory 204 may include details and variations as described below with reference to the memory 1604 of FIG. 16 below.

[0069] The I / O interface 206 may include interfaces to enable the user device 200 to interface with user inputs (e.g., keyboards, buttons, touchpads, switches, etc.) and outputs (e.g., screens, indicators, etc.). The I / O interface 206 may include details and variations as described below with reference to I / O interface 1606 of FIG. 16 below.

[0070] The network interface 208 may connect the user device 200 to other system components. For example, the user device 200 may be configured to communicate with an external device (e.g., the analyzer system 300) to deliver controls or receive results. As another example, the user device 200 may be configured to receive updates from, for example, a server or transmit data (user results, error reports, etc.) to the server. The network interface 208 may include details and variations as described below with reference to the network interface 1608 of FIG. 16 below.

[0071] FIG. 2 is a system diagram of an analyzer system 300, according to some embodiments.

[0072] The analyzer system 300 may include a processor 302, a memory 304, and a chip interface 306. The analyzer system 300 may further optionally include one or more of an I / O interface 308 and a network interface 310. The analyzer system 300 may be configured with a housing. The housing may be configured to physically receive a chip 100 (e.g., with the cinching mechanism 316). The chip 100, when received, may communicate with the analyzer system 300through, for example, the chip interface 306. The chip 100 and the analyzer system 300 may communicate to enable the chip 100 to transmit information about its systems (e.g., type of chip, feedback, signals, etc.) and the analyzer system 300 to transmit instructions to the chip 100.

[0073] The processor 302 may include a digital microfluidics (DMF) controller 312. The processor 302 may be configured to transmit (e.g., send or receive) data using any one or more of the chip interface 306, I / O interface 308, and network interface 310. The processor 302 may be configured to pull instructions from the memory 304 or from another component (e.g., an external device or the cloud). The processor 302 may be configured to pull and execute different instructions and / or modify instructions based on several factors (e.g., the type of chip therein inserted, user instructions, the test panel to be performed, updates from an external device or the cloud, calibrations steps, etc.). The processor 302 may include details and variations as described below with reference to the processor 1602 of FIG. 16 below.

[0074] The DMF controller 312 may be used to perform microfluidic operations on the chip 100. The DMF controller 312 may be configured to dispense droplets 110 (e.g., sample droplets) from the reservoir 102, move them between DMF electrodes 106, and conduct mixing operations. The DMF controller 312 may be configured to validate movement of the droplets 110 and provide some error correction.

[0075] The chip 100 (as described in greater detail below) may comprise, for example, a sandwich consisting of an area array of droplet-sized cells on the bottom, a cavity for droplets in the middle, and a continuous backplane which extends over all individual cells on the top. The cells and the backplane may be electrically insulated from the droplets by, for example, a thin coating. Droplets 110 can be induced to move from one cell region to another adjacent cell region through specific application of electrical forces (e.g., application of an alternating high voltage between an individual cell and the backplane). The DMF controller 312 can manipulate droplets 110 (e.g., microdroplets) on a platform by controlling a set of insulated electrodes. The DMF controller 312 can control the electronics in the chip 100 to drive movement of the droplets 110 across the chip 100 as needed.

[0076] In some embodiments, the chip 100 may have different configurations, sizes, and shapes of electrodes which may vary from chip to chip. Furthermore, the chip 100 may include other structures to alter droplet movement. Reagents printed on the chip 100 may be varied. TheDMF controller 312 may be configured to manipulate droplets 110 on different chips 100 depending on that chip’s 100 configuration, size, and shape of the electrodes and other factors.

[0077] When a polar liquid (e.g., blood plasma or water) sits atop a hydrophobic surface it will form into a droplet under surface tension. This orientation helps the liquid minimize the surface area with the hydrophobic surface. A drop of polar liquid sitting atop a hydrophilic surface will spread out and attempt to wet the surface.

[0078] The hydrophobicity of the surface can be modulated using electrical fields. For example, by placing a droplet 110 on a surface with an electrode thereunder, the electrode can modulate the electric fields applied to the droplet 110 thereby modulating the effective hydrophobicity / hydrophilicity of the surface. This process is called electrowetting-on-dielectric (EWOD). By modulating the electric fields of two adjacent cells in an array of cells, the DMF controller 312 can manipulate a droplet 110 to move between these surfaces.

[0079] The DMF controller 312 may further be configured to monitor feedback from a droplet 110 as it moves (or does not move) to validate and correct any deviations in intended movement patterns. Furthermore, this feedback can be used to verify droplet position and volumes. This may be convenient for fault-tolerant microfluidic operations. Moving droplets 110 may not always succeed and it is beneficial if the system 300 can correct itself rather than necessitating a new sample entirely. Viscous fluids (e.g., diluted plasma) may be especially difficult to control with microfluidics.

[0080] Droplet feedback systems can include, for example, a camera with, for example, computer-vision-aided tracking. These cameras however may be expensive and difficult to clean. This may make other more economical droplet feedback systems preferable for consumer products.

[0081] In one implementation, the DMF controller 312 can be configured to detect the presence of a volume of liquid on a surface. In such implementations, the DMF controller 312 can detect whether a set volume of liquid is present on a goal DMF electrode (which may be one in a series of goal DMF electrodes for complex or long range movement patterns). If the set volume is not detected, then the DMF controller 312 can carry out the operation again until, for example, the droplet 110 moves.

[0082] In another implementation, the DMF controller 312 can be configured to rely on capacitive feedback from a droplet 110 on the DMF electrode. For example, the DMF controller 312 may apply a transient DC voltage to each DMF electrode which results in a pulse with an amplitude roughly proportional to the droplet volume. Using these amplitudes, more precise measurement of volume of the droplet 110 can be obtained on a DMF electrode-by-electrode basis.

[0083] The analyzer system 300 includes a potentiostat 314 configured to control and receive signals from one or more electrochemical sensors on an inserted chip 100. The potentiostat 314 may be configured to perform, for example, assays using potentiodynamic operations such as, for example, cyclic-voltammetry (CV) or chronoamperometry (CA). The potentiostat 314 may also be configured to perform other electroanalytical methods.

[0084] The DMF controller 312 may be configured to transport droplets 110 to an electrochemical sensor and the potentiostat 314 may be configured to carry out an electrochemical operation on the droplet 110. For example, the potentiostat 314 may be configured to apply specific and / or dynamic voltages to the sample and facilitate measurement of the electrical characteristics (such as current).

[0085] The memory 304 may store instructions executable by the analyzer system 300. For example, the memory 304 may store instructions for a variety of different types of chips 100 and may select which instructions to execute based on, for example, the type of chip 100 inserted, a selection made by the user on the analyzer system 300, a selection made by the user on an external device, or some other method. The memory 304 may include details and variations as described below with reference to the memory 1604 of FIG. 16 below.

[0086] The chip interface 306 may be configured to interface with any chips 100 inserted or otherwise connected to the analyzer system 300. For example, a chip 100 may be seated within the analyzer system 300 and the chip 100 may be connected to the analyzer system 300. In particular, the DMF controller 312 may be connected to the DMF control system on the chip 100 and the potentiostat 314 may be connected to the electrochemical sensors on the chip 100. The chip interface 306 may include a single interface through which all connections are made or it may include a plurality of connections. The connection may be physical (enabling the analyzer system 300 to apply electrical forces through the chip 100) or it may be remote (for example, the analyzer system 300 activates the components in the chip 100 via a remote connection).

[0087] The I / O interface 308 may include interfaces to enable the analyzer system 300 to interface with user inputs (e.g., keyboards, buttons, touchpads, switches, etc.) and outputs (e.g., screens, indicators, etc.). The I / O interface 308 may include details and variations as described below with reference to I / O interface 1606 of FIG. 16 below.

[0088] The network interface 310 may connect the analyzer system 300 to other system components. For example, the analyzer system 300 may be configured to communicate with an external device (e.g., an user's mobile phone running an app) to deliver results or receive controls. As another example, the analyzer system 300 may be configured to receive updates from, for example, a server or transmit data (user results, error reports, etc.) to a server. The network interface 310 may include details and variations as described below with reference to the network interface 1608 of FIG. 16 below.

[0089] The analyzer system 300 may further comprise other optional components. For example, it may be configured with a vibrating component to vibrate the analyzer system 300 or parts thereof, for example, to dislodge a pinned droplet.

[0090] FIG. 3A is a top view of an embodiment analyzer system 300, according to some embodiments. FIG. 3B is a perspective view of an embodiment analyzer system 300, according to some embodiments.

[0091] An example chip 100 is illustrated as being in the analyzer system 300. As described above, the system analyzer 300 may be configured to interface with the chip 100 through a chip interface 306 to drive the digital microfluidic operations and / or to drive and receive information about the electrochemical sensors.

[0092] FIG. 3C is a side view of an embodiment analyzer system 300, according to some embodiments.

[0093] In some embodiments, a cinching mechanism 316 can couple the chip 100 with the analyzer 300 to help ensure electrical contact between the chip 100 and the analyzer 300. The cinching mechanism 316 can include a cinching motor 318, a cinching cam 320, and a moving platform 322. After being inserted into the analyzer 300, the chip 100 can be clamped in place. For example, the cinching motor 318 may actuate the cinching cam 320 and the moving platform 322. The moving platform 322 can push down on the chip 100. The moving platform's 322 verticalposition is set by the rotational position of the cinching cam 320 which can be powered by the cinching motor 318. Once cinched, pins on the bottom of the chip 100 may be in electrical contact with the analyzer's 300 pins. In some embodiments, the pins may be stationary. In some embodiments, the pins may be spring-loaded.

[0094] FIG. 4 is a perspective view of a chip 100 with digital microfluidic components, according to some embodiments.

[0095] The chip 100 (e.g., which may also be referred to herein as a cartridge) can comprise digital microfluidic components enclosed within a sealed cartridge. The digital microfluidic components can be used to manipulate droplets 110 (e.g., of a sample of blood or plasma thereof) within the enclosed space and to maneuver droplets 110 to reagents and sensor cells. The chip 100 may enclose the samples in an enclosed system that can be, for example, sealed from outside air or resist leakage of internal liquids.

[0096] FIG. 5A is a plan view of a chip 100, according to some embodiments.

[0097] The chip 100 includes a reservoir 102, a movement grid 104, and electrochemical sensors 108. As described above, the DMF components may connect or couple with an analyzer system 300 such that the analyzer system 300 can control the digital microfluidics on the chip 100 and sense and control the electrochemical sensors 108.

[0098] Samples may be provided to the chip 100 at or near the reservoir 102. The reservoir 102 may use electrowetting forces to hold a bulk sample in place and to deliver droplets 110 of the sample to the movement grid 104 for further operations.

[0099] The movement grid 104 includes a plurality of DMF electrodes 106. In some embodiments, the DMF electrodes 106 can be identical in construction or can be designed with specific regional functions. In some embodiments, a DMF controller 312 may be configured to selectively activate one or more of the DMF electrodes 106 to drive movement of a droplet 110 from DMF electrode 106 to DMF electrode 106. The movement grid 104 may also include deposits of any reagents, for example, stored in dry form on a particular DMF electrode 106 (described in greater detail below). During use, the movement grid 104 may receive or take a droplet 110 from the reservoir 102, move it using the DMF electrodes 106, optionally mix the droplet 110 with areagent stored on a particular DMF electrode 106, and bring the droplet to an electrochemical sensor 108 for analysis.

[0100] The electrochemical sensors 108 may include electrodes capable of monitoring and / or driving electroanalytical processes. There are twelve electrochemical sensors 108 shown on chip 100 (six along the top and six along the bottom). Other configurations are possible. In some embodiments, a potentiostat 314 can control the electrochemical sensors 108. Though described as electrochemical sensors 108, one or all of the sensors 108 may be configured for different sensor modalities.

[0101] Though one particular embodiment of the reservoir 102, movement grid 104, and electrochemical sensors 108 is illustrated, many more configurations are possible without deviating from the teachings of the present disclosure.

[0102] FIG. 5B is a plan view of a chip with a virtual bulk fluid reservoir 102, according to some embodiments.

[0103] In some embodiments, the reservoir 102 can be a virtual bulk fluid reservoir made up of numerous individual DMF electrodes 106.

[0104] The virtual reservoir 102 illustrated in FIG. 5B is larger (and specifically longer) than the reservoir 102 as illustrated in FIG. 5A. The larger reservoir 102 can hold a larger volume of sample liquid and it can also enable more dispensing strategies without encroaching on the movement grid 104. The larger reservoir 102 can allow the blood collector geometry (e.g., blood plasma separator 500) to sit outside the analyzer 300. Distancing the blood collector geometry from the analyzer 300 may be beneficial as it may reduce the risk of incompatibility as between the blood collector and the analyzer 300 should the blood collector be updated (e.g., newer versions of the blood collector can be developed without as much risk that it may not be usable with older models of an analyzer 300, for example due to spatial hindrance).

[0105] FIG. 6 is a top view of digital microfluidic electrodes 106 with droplets 110 contained thereon, according to some embodiments.

[0106] By manipulating the electrical forces surrounding the individual DMF electrodes 106, the droplets 110 may be compelled to move between adjacent DMF electrodes 106 or stay in place.

[0107] FIG. 7A is a cross section of a chip 100 across line A-A (FIG. 5A), according to some embodiments.

[0108] FIG. 7B is a cross-section of a chip 100 across line A-A (FIG. 5A), according to some embodiments.

[0109] The chip 100 may include a printed circuit board (PCB) 112, a dielectric layer 114, a bottom hydrophobic coating 118, an adhesive 116, a top hydrophobic coating 119, a top plate 120, and an enclosure 122 defining a space 126 for a sample droplet 110. An ITO spacer 127 may also define the cavity 126. The chip 100 may also include an EC spacer 124, an ITO spacer 127 and electrochemical sensors 108.

[0110] The PCB 112 may comprise a printed circuit board with or without solder mask. The PCB 112 can be divided into DMF electrodes 106 for droplet movement and microfluidic operations and, for example, electrochemical sensor 108 electrodes for running assays (as seen in FIG. 5A). The electrodes may coated using an immersion gold process with a protective layer such as palladium beneath to improve electrochemical signal reliability and resist corrosion during storage.

[0111] The dielectric layer 114 may be used to induce electrowetting-on-dielectric, the phenomenon that allows for droplet 110 movement on the grid. In some embodiments, the dielectric layer 114 can be a UV / heat curable liquid with a high dielectric strength. Thickness of the dielectric layer 114 may be controlled by the fabrication process used such as spin coating, dip coating etc. In some embodiments, 2.5 pm thick polyester film can be used. In some embodiments, 10 pm thick polyester film can be used. In some embodiments, 7.5 pm polyimide film can be used. In some embodiments, the dielectric layer 114 may be 5-10 pm thick. In some embodiments, the dielectric layer 114 may be 10 pm thick. Thinner dielectric layers can enable droplet movement at lower actuation voltages. The dielectric layer 114 is bonded to the PCB 112 using an adhesive 116. In some embodiments, the adhesive 116 is an adhesive coating applied to one side of the PCB 112.

[0112] Hydrophobic coatings 118, 119 may be used to coat the dielectric layer 114 and top plate 120 to aid droplet 110 movement and create the contact angle required for movement by electrowetting-on-dielectric. In some embodiments, Cytonix Fluoropel PFC 1101V can be used.After coating the dielectric layer 114, the Fluoropel can be cured. The thickness of the hydrophobic coatings 118, 119 may be less than one micrometer.

[0113] ITO spacer 127 (which may be a spacing adhesive) can be used to hold the top plate 120 in place and provide enough space for the droplets 110 to move underneath. In some embodiments, the spacer 127 height may be between 100 and 300 micrometers. In one specific embodiment, the spacing may be approximately 235 micrometers.

[0114] The top plate 120 can be a conductive top plate to close the circuit through the PCB 112, dielectric layer 114, and droplets 110. In some embodiments, the top plate 120 can be connected to the base PCB 112 using a deformable conductive material (e.g., copper tape) at, for example, the edge. In some embodiments, the top plate 120 may be Indium-Tin-Oxide (ITO)- coated glass. Transparency allows the droplets 110 to be seen during movement. Other conductive rigid materials such as materials of another PCB or injection molded conductive parts may be used when direct visual contact with the droplets 110 is not required.

[0115] Enclosure 122 can provide a sealed case to seal any reagents (described in greater detail below) and hydrophobic coatings 118 and 119 inside the chip 100 for safe handling and disposal by consumers.

[0116] On the periphery of the chip 100 are the electrochemical sensors 108. The electrochemical sensors 108 may optionally interoperate with the EC spacer 124 and hydrophilic layers 136 to receive the sample. In some embodiments, the electrochemical sensors 108 do not use hydrophilic layers 136 to receive the sample (e.g., the hydrophobic coating 119 and / or 118 may be masked to encourage the sample droplet 110 to enter the sensor 108), as seen in FIG. 7A. In some embodiments, the EC spacer provides a region for the electrochemical reaction to be carried out (e.g., spacing any hydrophilic layers 136). In some embodiments, the hydrophilic layers 136 can attract the sample droplet 110 into the sensor 108. In some embodiments, the hydrophilic layers 136 can overlap on the hydrophobic coating 118 (seen in the bottom hydrophilic coating 136 of FIG. 7B). This may advantageously improve the reliability of the electrochemical sensors 108 by improving droplet transfer. The electrochemical sensors 108 are described in greater detail below.

[0117] FIG. 8 is a plan view of a chip 100 with reagents 128 provided thereon, according to some embodiments.

[0118] In some embodiments, some chips 100 may include deposited reagents 128 (inclusive of reagents 128a, 128b, and 128c). These reagents 128 may be any reagents required to be mixed into plasma / diluent droplets 110 before moving to the electrochemical sensors 108 (inclusive of sensors 108a and 108b). In some embodiments, different reagents 128 may be placed on the grid which may ultimately be tested by different electrochemical sensors 108 for different analytes or phenomena. For example, one droplet 110 may be directed to mix with reagent 128a and then analyzed by sensor 108a while another droplet 110 may be directed to mix with reagent 128b, made to wait while a reaction occurs, mixed with reagent 128c, and analyzed by sensor 108b which may be configured differently than sensor 108a. Example reagents sensors 108 can include electrochemical sensors, dilution factor sensors, total cholesterol (TC) sensors, high-density lipoprotein (HDL) sensors, and triglyceride (TRG) sensors. Furthermore, some sensors 108 may be coated with coatings or otherwise configured to carry out a particular analysis.

[0119] FIG. 9A illustrates a cross section of a single electrochemical sensor 108 across line B-B (FIG. 5A), according to some embodiments.

[0120] The electrochemical sensor 108 may be provided on a PCB 112. The electrochemical sensor 108 may comprise a three-electrode set up with a working electrode 130, a counter electrode 132, and a reference electrode 134. Other electrode set ups are conceived (e.g., a counter electrode 132 split into two halves 132A and 132B). The electrochemical sensor 108 may be situated underneath one or more hydrophilic layers 136. In some embodiments, this may include a multi-layered assembly that creates a cavity with the electrodes exposed to the liquid. The assembly may consist of multiple hydrophilic layers 136, spacer adhesives 124 composed of double and / or single sided tapes (shown in FIG. 9B). The hydrophilic layers 136 could be natively hydrophilic, or made hydrophilic through the addition of different liquids dried on the surface such as sugars, salts, surfactants, hydrogels etc. The working electrode 130 may, in some embodiments, be coated with a coating 131 , for example a membrane that may, for example be enzyme modified. The droplet reaction mixture 138 (e.g., a plasma reaction mixture) may be situated on the working electrode and be analyzed by the electrochemical sensor 108. The coating 131 may include a porous membrane. This porous membrane may be deposited on the working electrode 130 using a deposition printer. The coating 131 may contain enzymes, antibodies, and reagents as required.

[0121] As described above, the electrochemical sensor 108 may be made to perform, for example, assays using potentiodynamic operations such as, for example, cyclic-voltammetry (CV) or chronoamperometry (CA). Other electroanalytical methods are conceived. Other electrochemical operations are conceived of as being carried out with the electrochemical sensor 108 such as applying specific and / or dynamic voltages to the sample and measuring the current observed. The electrochemical sensor 108 may be controlled by a potentiostat 314 on an analyzer system 300.

[0122] FIG. 9B is a cross-sectional elevation view of a multilayer electrochemical sensor 108, according to some embodiments.

[0123] Precipitating certain sample components (e.g. cholesterols) on the movement grid 104 can degrade movement (up to and including a complete stop or "pinning") in the vicinity due to accelerated biofouling of the electrowetting surface. Using a hydrophilic layer 136 such as a reagent-doped mesh to precipitate e.g. cholesterols instead of carrying the precipitation out on the movement grid 104 can obviate the issue of degraded movement because the droplet 110 is already in its final resting place and there is no need to move it away from that location afterwards. For example, the sample droplet 110 may be drawn into the upper droplet reaction mixture portion 138, react with a reagent doped in the lower hydrophobic layer 136 to precipitate a component of the sample droplet 110, draw the sample droplet into the lower droplet reaction mixture portion 138 to contact the working electrode 130.

[0124] FIG. 9C is a perspective view of an electrochemical sensor 108 with reagents provided thereon, according to some embodiments.

[0125] In some embodiments, the hydrophilic layers 136 can also be loaded with reagents. This can enable the reagents to be mixed directly above the sensor 108. In some embodiments, a hydrophilic layer 136 may be in contact with the electrochemical sensor 108 (cell A). In some embodiments, the hydrophilic layers 136 may both be above the electrochemical sensor 108 (cell B). In some embodiments, the hydrophilic layers 136 may be above the electrochemical sensor 108 in much closer proximity to it (cell C). The heights may vary.

[0126] FIG. 10A is a plan view of an electrochemical sensor 108, according to some embodiments.The electrochemical sensor 108 may be configured with a three-electrode set up. The electrochemical sensor 108 may be configured with a circular central working electrode 130, and a counter electrode 132, and a reference electrode 134.

[0127] The electrochemical sensor 108 may include gold. Standard PCB manufacturing techniques may be used. The electrochemical sensor 108 may have many sizes and shapes / numbers of electrodes while falling within the teachings of this description.

[0128] The electrochemical sensor 108 may include a reservoir made up of a small cut-out in, for example, a Fluoropel layer above to the electrodes allow a microdroplet of fluid to sit on the electrode.

[0129] FIG. 10B is a plan view of an electrochemical sensor 108 with a split counter electrode 132 arrangement, according to some embodiments.

[0130] The counter electrode 132 can be split into two electrically connected halves 132A and 132B using through-hole vias. This can maintain the three-electrode configuration though the counter electrode 132 is split into two halves 132A and 132B. Splitting the counter electrode 132 into two halves 132A and 132B can provide a convenient avenue for the droplet 110 to flow through on its way to fully loading the electrochemical sensor 108 (as illustrated).

[0131] It may be beneficial to provide the reference electrode 134 furthest away from the movement grid 104 so that the potential of the open circuit of the three-electrode cell can be used to determine whether the cell has been properly filled (e.g., the circuit has been completed). It is generally preferable to keep the reference electrode 134 and the counter electrode 132 close to the working electrode 130. Given that the reference electrode is preferably further from the movement grid 134, then the counter electrode 132 accordingly ends up in that position. By splitting the counter electrode 132 into two halves 132A and 132B, the droplet 110 does not need to overcome an energy barrier at the inner edge of the counter electrode 132 (the edge of the counter electrode 132 close to the working electrode 130). Further, by splitting the counter electrode 132, the droplet 110 may not first fill a counter electrode 132 which can restrict further movement into the sensor 108 because after filling the counter electrode 132, the droplet 110 may preferentially flow along the counter electrode’s 132 surface (and sometimes even to the reference electrode 134) which may prevent the working electrode 130 from being covered. Splitting the counter electrode 132 may accordingly improve the transfer reliability because thedroplet 110 may flow into the working electrode 130 more uniformly and can do so without having to traverse a counter electrode 132.

[0132] FIG. 10C is a plan view of an electrochemical sensor 108 with carbon nano-tubes 133, according to some embodiments.

[0133] Providing a carbon nano-tube porous ink 133 to the electrochemical sensor 108 can help entrap active biorecognition elements and other reagents within the vicinity of the working electrode 130 while enhancing the stability of the electrochemical sensor 108. The counter electrode 132 is split in two halves 132A and 132B. The porous ink (membrane) 133 can consist of a binder, such as hydroxyethyl cellulose and / or cellulose acetate, to encapsulate the active biorecognition elements such as enzymes, antibodies, aptamers, and / or DNA probes; cofactors such as ATP, magnesium chloride, magnesium sulfate, magnesium acetate, and / or NAD(P)H; stabilizers, such as bovine serum albumin (BSA), lactose, D-mannitol and / or trehalose; electron mediator, such as potassium ferrocyanide, potassium ferricyanide, methylene blue, 1- methoxy-5-methylphenazinium methyl sulfate (MPMS) and / or ruthenium hexamine; functionalized multi-walled carbon nanotubes (MWCNTs), polyaniline (PANI) and / or functionalized gold nanoparticles to enhance the active surface area of the working electrode 130; and non-ionic surfactant, such as Tween20, and / or Triton™ X-100, to facilitate the homogeneous dispersion of reagent on the working electrode 130.Microfluidic transfer to EC electrodes

[0134] As noted above, the dielectric layer 114 is used to induce electrowetting-on-dielectric to effect droplet 110 movement on the grid 104. In some embodiments, the dielectric layer 114 extends across DMF electrodes 106, but not across the electrochemical sensors 108. In such embodiments, electrowetting-on-dielectric is used to effect movement of a droplet 110 to an edge of movement grid 104 proximate an electrochemical sensors 108, but is not used to effect movement of the droplet 110 onto a electrochemical sensor 108. In such embodiments, another mechanism may be used to effect movement of a droplet 110 onto an electrochemical sensor 108.

[0135] FIG. 11A illustrates a bridge 150 for moving a droplet 110 the movement grid 104 to an electrochemical sensor 108, according to some embodiments.

[0136] In some embodiments, the bridge 150 is formed to join one or more DMF electrodes 106 at the edge of movement grid 104 and an adjacent electrochemical sensor 108. The bridge 150 may at least partially overlay the one or more DMF electrodes 106 and at least partially overlay the adjacent electrochemical sensor 108 and extend therebetween. The bridge 150 may be formed of a hydrophilic material that draws a droplet 110 from a DMF electrode 106 to an adjacent electrochemical sensor 108 using a hydrophilic force and / or capillary force. In some embodiments, vibrational forces may be applied to urge movement of droplet 110 across the bridge 150.

[0137] In some embodiments, the bridge 150 is formed as a hydrophilic coating applied to at least part of a DMF electrode 106 and at least part of an adjacent electrochemical sensor 108. In some embodiments, this coating includes a mono, dimer, or polymer coating. In some embodiments, this coating may be a coating formed of glucose, trehalose, or the like. When a droplet 110 is moved to a DMF electrode 106, it comes into contact with the coating and is drawn to an adjacent electrochemical sensor 108. In some embodiments, the droplet 110 may dissolve the coating as it moves to electrochemical sensor 108. In some embodiments, the bridge 150 may include surfactant coatings.

[0138] In some embodiments, the bridge 150 may be formed using a deposition printer. In some embodiments, the bridge 150 may be formed by masking regions of chip 100 before applying a hydrophobic coating during fabrication to create cut-outs for applying the bridge 150.

[0139] In some embodiments, the bridge 150 is formed of a hydrophilic polymer matrix such as, for example, hydroxyethyl cellulose. In some embodiments, the bridge 150 has a scaffold structure.

[0140] In some embodiments, the bridge 150 includes a membrane formed of a dried hydrogel. This membrane may draw a droplet 110 from a DMF electrode 106 to an adjacent electrochemical sensor 108 as the hydrogel rehydrates and swells with the sample fluid. In some embodiments, the membrane may be permeable to airflow allowing air displacement to facilitate fluid transport, and without need for a vent to exhaust displaced air.

[0141] In some embodiments, the hydrophilic mesh consists of a surfactant covered mesh.

[0142] In some embodiments, the bridge 150 consists of a multi-layered assembly. The assembly may consist of multiple hydrophilic layers, spacer adhesives composed of double-sided tapes and single-sided tapes. The hydrophilic layers can be natively hydrophilic, or made hydrophilic through the addition of different liquids dried on the surface such as sugars, salts, surfactants, hydrogels etc.

[0143] In some embodiments, the membrane may be placed directly in contact with a DMF electrode 106 and / or an adjacent electrochemical sensor 108. In some embodiments, the membrane may extend in a space below top plate 120 (e.g., in space 126). In some embodiments, the membrane may extent in contact with a bottom surface of top plate 120.In some embodiments, the membrane may be formed of another hydrophilic material such as nylon mesh, stainless steel mesh, dried poly-vinyl alcohol, hydroxyethyl cellulose, hydrophilic film or the like, or combinations thereof. In some embodiments, the bridge 150 may be a treated nylon mesh.

[0144] In some embodiments, the bridge 150 is applied to a bottom surface of top plate 120. For example, the bridge 150 may form at least part of hydrophilic top layer 136 (e.g., FIG. 9A-9C) that extends at least partially over top one or more DMF electrodes 106 and at least partially over an adjacent electrochemical sensor 108 and extend therebetween.

[0145] In some embodiments, the top layer 136 is maintained at a desired height above the PCB 112 using spacing adhesive 116. In some embodiments, the top layer 136 may be patterned to define movement paths for droplets between the movement grid 104 and an electrochemical sensor 108.

[0146] In some embodiments, spacing adhesive 116 may be applied to define movement paths for droplets to move between the movement grid 104 and one or more electrochemical sensors 108.

[0147] In some embodiments, the top layer 136 may be used in combination with hydrophilic coatings disclosed herein. Such coatings may be applied to at least parts of a DMF electrode 106, an electrochemical sensor 108, and spacing adhesive 116.

[0148] In some embodiments, the bridge 150 may extend between a DMF electrode 106 and an electrochemical sensor 108 as a tracer or a tail.

[0149] FIG. 11 B illustrates the movement grid 104 and electrochemical sensors 108 with a cutout 146, according to some embodiments.

[0150] Adding a cutout 146 can reduce the chances of a bubble forming on top of the electrochemical sensor 108. Bubbles can displace sample fluid 110 which prevents good signal determination and thus preventing bubbles can be beneficial. Bubbles can also pop, for example, mid-measurement and perturb an ongoing reaction.Scheduling EC measurements in between DMF movement steps

[0151] Embodiments of the methods and devices disclosed herein may be used to perform electrochemistry assays that are sensitive to electrical noise. Electrical noise may include noise generated by one or more components of a chip 100, a user device 200, and / or an analyzer system 300.

[0152] In some embodiments, the DMF controller 312 is configured to perform microfluidic operations on the chip 100 in such a way to avoid ongoing or upcoming EC measurements using potentiostat 314. In some embodiments, for example, actuation of high-voltage signals to effect microfluidic operations, which may introduce electrical noise, are timed to avoid affecting EC measurements. In such embodiments, DMF controller 312 and potentiostat 314 cooperate to coordinate scheduling of their respective operations. In some embodiments, DMF movements and EC measurements are scheduled to be interleaved., which may reduce the time taken before a sample droplet 110 is subject to EC measurements (e.g., before an entire DMF movement sequence for multiple droplets 110 has been completed).

[0153] Conveniently, in some embodiments, such interleaving may improve droplet movement efficiency. Conveniently, in some embodiments, such interleaving may facilitate the performance of assays that are time-sensitive, e.g., requiring EC measurements to be taken within a shorter period of time. Conveniently, in some embodiments, the assay may be adjusted (e.g., DMF operations may be adjusted) based on a subset of EC measurement (e.g., measurements on a subset of droplets).Low current potentiostat measurement for monitoring microfluidic droplet movement to electrochemistry electrodes.

[0154] In some embodiments, potentiostat 314 is configured to determine whether sample fluid has been moved to an electrochemical sensor 108 such that potentiostat 314 can transition to a ready state for performing a desired assay. Potentiostat 314 does not transition to the ready state if, for example, the sample fluid has not moved in sufficient volume to the electrochemical sensor 108, or if the sample fluid is not making a required amount of contact with one or more electrodes of the electrochemical sensor 108. In some embodiments, it may be difficult to assess when to enter such ready state visually because certain EC measurements are light sensitive, and thus cannot be exposed to light resources for the purpose of observation.

[0155] Conveniently, in some embodiments, determination of readiness using potentiostat 314 may help avoid making an EC measurement prematurely (e.g., before the sample fluid has completed its movement to the electrochemical sensor 108, which may affect the accuracy of that measurement and / or subsequent measurements. Conveniently, in some embodiments, such determination of readiness using potentiostat 314 may help avoid making an EC measurement when a microfluidic operation has failed. In some embodiments, transfer can be checked by detecting for the absence of the droplet 110 on the last DMF electrode, this may be used in combination with the EC detection mentioned here.

[0156] The potentiostat 314 is used to make a determination of readiness by performing one or more pilot assays before performing the desired assay (which may also be referred to as a primary assay). The pilot assays are performed using voltage in a range significantly lower than a voltage range for the primary assay. The voltage range of the pilot assay is selected to minimize the effect on EC measurement results of the primary assay. For example, in some embodiments, the potentiostat 314 performs a primary assay at a predetermined voltage range such as -0.3 V to 0.3 V. In such embodiments, a pilot assay may be performed in a lower voltage range. In such embodiments, a pilot assay may be performed, for example, in a lower predetermined voltage range such as -0.1 V to 0.1 V.

[0157] The application of voltage in a pilot assay may generate a pilot EC measurement (e.g., of a lower current). This EC measurement may be compared against expected measurements (e.g., using one or more predetermined thresholds or heuristics) to make a determination of readiness for the primary assay. In some embodiments, such determination may include assessing a likelihood that a sufficient volume of sample fluid is occupying the electrodes of the electrochemical sensor 108. If the determination indicates a ready state, then the potentiostat 314may progress to the primary assay. If the determination fails to indicate a ready state, then potentiostat 314 may perform the pilot assay again after a predetermined delay. If the determination fails to indicate a ready state after a predetermined number of pilot assays have been performed, then an error is detected.

[0158] In some embodiments, in response to such error detection, an alert or notification may be issued to the user (e.g., by way of a signal transmitted from analyzer system 300 to user device 200). The alert may be presented to the user via app 210. Conveniently, such detection may prevent the presentation of invalid data to the user.EC sensor current-overload detection

[0159] Damage or a manufacturing defect of an electrochemical sensor 108 or related electronic components (e.g., in PCB 112) can lead to corrosion or other deterioration of an electrode of the electrochemical sensor 108. Operation of the potentiostat 314 in the presence of such an electrode may cause undesired EC measurements such as, for example, a large spike in measured current, which may impair the ability of the electrochemical sensor 108 to obtain a desired signal. In such situations, continued application of voltage by the potentiostat 314 to that electrochemical sensor 108 may have undesirable effects such as, e.g., sample electrolysis, which may in turn result in unintended chemical products.

[0160] In some embodiments, the potentiostat 314 is configured to detect undesired EC measurements, as may be caused by corrosion or other deterioration of an electrode of electrochemical sensor 108. For example, potentiostat 314 may be configured to detect an error in the form of an unexpected increase (or rate of increase) in an EC measurement (e.g., measured current) from a given electrochemical sensor 108. In response to such error detection, the potentiostat 314 may deactivate an input voltage to that electrochemical sensor 108. Conveniently, such deactivation may reduce the generation of unintended chemical products. In some embodiments, in response to such error detection, an alert may be issued to the user (e.g., by way of a signal transmitted from analyzer system 300 to user device 200. The alert may be presented to the user via app 210). Conveniently, such detection may prevent the presentation of invalid data to the user.

[0161] In some embodiments, error detection may be used to adjust routing of sample droplets 110, e.g., to use an electrochemical sensor 108 other than the electrochemical sensor 108 for which an error has been detected.Vias-in-pad

[0162] Embodiments of the methods and devices disclosed herein may be used to perform electrochemistry assays in which the quality of EC measurements (e.g., signal strength) is dependent on an electrode’s active surface area. For example, signal strength may increase as active surface area increases. Conveniently, in some embodiments, this may allow assays to be performed on samples of certain low-concentration analytes.

[0163] FIG. 12A is a top view an electrode, in accordance with some embodiments. The electrode is formed with one or more vias-in-pad 352. Each via-in-pad 352 combines a PCB through-hole via (that extend one or more PCB layers) with a corresponding pad. A via-in-pad 352 may be distinguished from a via connected by a trace to a pad. Each via-in-pad 352 may be used as an electrode of an electrochemical sensor 108 (e.g., a working electrode 130, a counter electrode 132, a reference electrode 134, etc.).

[0164] In some embodiments, a via-in-pad 352 may be used as an electrode for another component (e.g., as a DMF electrode 106), as depicted in FIG. 12B.

[0165] In some embodiments, a via-in-pad 352 is formed as a via through a pad (e.g., by drilling), followed by filling and plating over the via. For example, one example process for forming a via-in-pad 352 includes drilling a hole at a desired via location, plating the hole with a material such as copper, filling the hole with a material such as resin, and then plating over the filled hole. A via-in-pad 352 may be formed on a PCB with a surface finish such as ENIG, ENEPIG, hard gold, immersion silver, or the like. Such process may result in small raised or sunken features (e.g., divots, protrusions, or the like) on the top surface of the PCB, which may otherwise be planar.

[0166] In some embodiments, these raised features are desirable because when formed on an electrode of an electrochemical sensor 108, the electrode’s active surface area is increased when the electrode is in contact with sample fluid. Further, multiple vias-in-pad 352 can be formed in a single electrode to further increase the active surface area.

[0167] The diameter of vias and via-to-via spacing may vary from embodiment to embodiment.

[0168] Conveniently, in some embodiments, the via-in-pad 352 can be formed during a conventional PCB manufacturing process, thereby avoiding the cost of an additional manufacturing step.Wire electrode.

[0169] FIG. 13 is an elevation view of an electrode 400, in accordance with some embodiments. The electrode 400 may be used to implement an electrode of an electrochemical sensor 108 (e.g., a working electrode 130, a counter electrode 132, a reference electrode 134, etc.). As depicted, the electrode 400 includes a base 402 and a wire loop 404 extending above the base 402. Each end of the wire loop 404 is wire-bonded to the base 402 using thermocompression, ultrasonic, thermosonic wire-bonding or the like.

[0170] In some embodiments, multiple wire loops 404 may be formed over the base 402.

[0171] The base 402 may be formed with a conventional hard surface finish such as ENIG, ENEPIG, hard gold, or the like. The wire loop 404 may be formed of high-purity gold wire. The gauge of wire forming the wire loop 404 may be selected based on signal requirements.

[0172] During operation, when a fluid sample 115 is moved on to the base 402, the wire loop 404 is at least partially immersed in the fluid sample 115. As the fluid sample 115 is in contact with both the base 402 and the wire loop 404, the electrode’s active surface area is increased compared to an electrode without a wire loop 404. As the surface area of the base 402 does not need to increase compared to an electrode without a wire loop 404, the quantity of fluid sample 115 and hence the volume of the droplet 110 to be moved to the electrode 400 does not need to be increased.

[0173] In some embodiments, wire bonding may be used to connect a wire joining multiple planar electrodes, allowing such multiple planar electrodes to function as a single electrode.PCB cavities

[0174] Embodiments of the methods and devices disclosed herein may be used to perform electrochemistry assays in which the quality of EC measurements (e.g., signal strength) is dependent on a sample height. For example, signal strength may be approximately proportional to the sample height.

[0175] In some embodiments, a maximum sample height is defined by a height of the space between the top of an electrode of an electrochemical sensor 108 and the top plate 120. FIG. 14 is a cross-sectional elevation view of an electrochemical sensor 108 (e.g., the electrodes 130, 132, and 134) disposed in a cavity 500 of PCB 112, in accordance with some embodiments. Conveniently, in some embodiments, by disposing the electrochemical sensor 108 in the cavity 500, the maximum sample height may be increased. In particular, the sample height may extend below a top surface of the PCB 112.

[0176] In the depicted embodiment, a PCB 112 includes a cavity 500 formed thereon, extend from a top surface. The cavity extends into PCB 112 (without penetrating through the PCB 112) such that the electrochemical sensor 108 may be mounted on a bottom surface of the cavity 500. The depth of the cavity 500 may depend on the thickness of the PCB 112, which may depend on, for example, the number of inner PCB layers. One or more electrodes of the electrochemical sensor 108 (e.g., the electrodes 130, 132, and 134) may be mounted on this bottom surface. By lowering the electrodes into the cavity 500, more space is provided above the electrodes to accommodate a fluid sample. Thus, a fluid sample of a greater height (and greater volume) may be placed on the electrode. Conveniently, in some embodiments, this may improve the quality of EC measurements obtained from the electrochemical sensor 108. Conveniently, this may allow assays to be performed on samples of certain low-concentration analytes.EC wires suspended over DMF electrodes

[0177] FIG. 15 is a elevation view of an electrochemical sensor 108, according to some embodiments. As depicted, a droplet 110 rests on a DMF electrode 106 of a movement grid 104. The electrochemical sensor 108 is formed as a plurality of wires 602 which are strung to be suspended above the DMF electrodes 106 of the movement grid 104. In some embodiments, each wire 602 may be held in tension by supports at opposing ends to remain spaced from both the grid 104 and a surface above it (e.g., the top plate 120). In some embodiments, a wire 602 may be strung to be approximately 20-50 micrometers above the grid 104. In one specific embodiment, a wire 602 may be strung 30 micrometers above the grid 104.

[0178] Each of the wires 602 is in electrical communication with the potentiostat 314 and the set of wires 602 functions as the electrodes of an electrochemical sensor 108 (e.g., a working electrode 130, a counter electrode 132, a reference electrode 134, etc.)

[0179] The wires 602 may be formed of a suitable conductive material such as gold, silver, carbon, or the like. The gauge of wire forming a wire 602 may be selected based on signal requirements. In some embodiments, this gauge of wire may have a diameter of approximately 25 micrometres. The diameter of wire 602 may be selected so that each wire 602 avoids contact with other wires 602, and with a top surface (e.g., top plate 120) and a bottom surface (e.g., grid 104). In some embodiments, a wire 602 may be formed as a monofilament.

[0180] When a droplet 110 is moved to a DMF electrode 106 beneath a set of wires 602, droplet 110 is brought into contact with those wires 602. For example, the wires 602 may be immersed in a droplet 110 and extend therethrough. Since the wires 602 function as electrodes of electrochemical sensor 108, EC measurements may be obtained from the droplet 110 using the wires 602.

[0181] Conveniently, in the depicted embodiment, EC measurements are obtained while a droplet 110 remains on the movement grid 104. This allows droplet 110 to be moved before and / or after EC measurements.

[0182] In some embodiments, one or more wires 602 may be functionalized with a coating. For example, in an example Vitamin D assay, one or more wires 602 may be coated with a Vitamin D antibody. In this assay, a droplet 110 may be moved to contact one or more wires 602 coated with Vitamin D antibody, with some Vitamin D binding to the antibodies. Then a wash step can be performed to wash away material that is not bound to the antibodies. After this wash step, EC measurements may be obtained without interference from material that has been washed away.

[0183] In some embodiments, a set of wires 602 may extend across multiple DMF electrodes 106, forming an electrochemical sensor 108 above each of those DMF electrodes 106. During operation, a set of wires 602 may be used to perform EC measurements on a droplet 110 on a first DMF electrode 106. Then, the droplet 110 can be moved off of the first DMF electrode 106 and another droplet can be moved on a second DMF electrode 106. Then, the same set of wires 602 may be used to perform EC measurements on the droplet 110 on the second DMF electrode 106.

[0184] In some embodiments, wires 602 may be strung across the movement grid 104 to provide an electrochemical sensor 108 above each DMF electrode 106 in the movement grid 104. In some embodiments, an electrochemical sensor 108 may be provided using wires 602 at a subset of DMF electrodes 106. In some embodiments, multiple overlapping layers of 602 may be strung across movement grid 104 at different heights to provide multiple electrochemical sensors 108 above one or more DMF electrodes 106.

[0185] In some embodiments, a set of wires 602 forming an electrochemical sensor 108 may extend in parallel with another set of wires 602 forming another electrochemical sensor 108. In some embodiments, a set of wires 602 forming an electrochemical sensor 108 may extend at an angle to (e.g., be perpendicular to) another set of wires 602 forming another electrochemical sensor 108.

[0186] In some embodiments, potential advantages of bifurcating the analyzer system 300 and the chip 100 may be that the components required for controlling and carrying out sample testing can be reused while components that contact the sample or that are depleted or contaminated by sample testing can be replaced. This can enable reuse of some components (one analyzer system 300 can be reused). This can further enable compatibility with a plurality of chips 100 (e.g., different chips 100 may be configured for different test panels) that do not require expert set up or cleaning between uses (chips 100 can be manufactured such that users need not apportion reagents or clean the chips 100 during or after use).

[0187] As described above, in some embodiments, a chip 100 and an analyzer system 300 may be integral to one another without deviating from the teachings of this disclosure. For example, a system which is configured to run the provision of sample testing and the specific sample testing components may be carried out in one integral component. Such integral implementations may, for example, be configured for single uses or may be configured to be replenished or otherwise reconfigured and subsequently reused.

[0188] The systems and methods described herein can be accomplished using external devices and servers. For example, an analyzer system 300 may communicate results of testing to an external device once the testing is complete or it may receive updates or instructions from a server. The systems and methods described herein can be compatible within broader healthcare treatment solutions.Computer Implementation Details

[0189] The embodiments of the devices, systems and methods described herein may be implemented in a combination of both hardware and software. These embodiments may be implemented on programmable computers, each computer including at least one processor, a data storage system (including volatile memory or non-volatile memory or other data storage elements or a combination thereof), and at least one communication interface.

[0190] Program code is applied to input data to perform the functions described herein and to generate output information. The output information is applied to one or more output devices. In some embodiments, the communication interface may be a network communication interface. In embodiments in which elements may be combined, the communication interface may be a software communication interface, such as those for inter-process communication. In still other embodiments, there may be a combination of communication interfaces implemented as hardware, software, and combination thereof.

[0191] Throughout the foregoing discussion, numerous references will be made regarding servers, services, interfaces, portals, platforms, or other systems formed from computing devices. It should be appreciated that the use of such terms is deemed to represent one or more computing devices having at least one processor configured to execute software instructions stored on a computer readable tangible, non-transitory medium. For example, a server can include one or more computers operating as a web server, database server, or other type of computer server in a manner to fulfill described roles, responsibilities, or functions.

[0192] The technical solution of embodiments may be in the form of a software product. The software product may be stored in a non-volatile or non-transitory storage medium, which can be a compact disk read-only memory (CD-ROM), a USB flash disk, or a removable hard disk. The software product includes a number of instructions that enable a computer device (personal computer, server, or network device) to execute the methods provided by the embodiments.

[0193] The embodiments described herein are implemented by physical computer hardware, including computing devices, servers, receivers, transmitters, processors, memory, displays, and networks. The embodiments described herein provide useful physical machines and particularly configured computer hardware arrangements. The embodiments described herein are directed to electronic machines and methods implemented by electronic machines adapted for processingand transforming electromagnetic signals which represent various types of information. The embodiments described herein pervasively and integrally relate to machines, and their uses; and the embodiments described herein have no meaning or practical applicability outside their use with computer hardware, machines, and various hardware components. Substituting the physical hardware particularly configured to implement various acts for non-physical hardware, using mental steps for example, may substantially affect the way the embodiments work. Such computer hardware limitations are clearly essential elements of the embodiments described herein, and they cannot be omitted or substituted for mental means without having a material effect on the operation and structure of the embodiments described herein. The computer hardware is essential to implement the various embodiments described herein and is not merely used to perform steps expeditiously and in an efficient manner.

[0194] FIG. 16 is a schematic diagram of a computing device 1600, according to some embodiments. As depicted, computing device 1600 includes at least one processor 1602, memory 1604, at least one I / O interface 1606, and at least one network interface 1608. The computing device 1600 and aspect thereof may be provided within the user device 200 and the analyzer system 300 of FIG. 2.

[0195] For example, and without limitation, the computing device 1600 may be a server, network appliance, set-top box, embedded device, computer expansion module, personal computer, laptop, personal data assistant, cellular telephone, smartphone device, LIMPC tablets, video display terminal, gaming console, electronic reading device, and wireless hypermedia device or any other computing device capable of being configured to carry out the methods described herein

[0196] For simplicity only one computing device 1600 is shown but system may include more computing devices 1600 operable by users to access remote network resources and exchange data. The computing devices 1600 may be the same or different types of devices. The computing device 1600 at least one processor, a data storage device (including volatile memory or nonvolatile memory or other data storage elements or a combination thereof), and at least one communication interface. The computing device components may be connected in various ways including directly coupled, indirectly coupled via a network, and distributed over a wide geographic area and connected via a network (which may be referred to as “cloud computing”).

[0197] Each processor 1602 may be, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, a programmable read-only memory (PROM), or any combination thereof.

[0198] Memory 1604 may include a suitable combination of any type of computer memory that is located either internally or externally such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically- erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like.

[0199] Each I / O interface 1606 enables computing device 1600 to interconnect with one or more input devices, such as a keyboard, mouse, camera, touch screen and a microphone, or with one or more output devices such as a display screen and a speaker.

[0200] Each network interface 1608 enables computing device 1600 to communicate with other components, to exchange data with other components, to access and connect to network resources, to serve applications, and perform other computing applications by connecting to a network (or multiple networks) capable of carrying data including the Internet, Ethernet, plain old telephone service (POTS) line, public switch telephone network (PSTN), integrated services digital network (ISDN), digital subscriber line (DSL), coaxial cable, fiber optics, satellite, mobile, wireless (e.g. Wi-Fi, WiMAX), SS7 signaling network, fixed line, local area network, wide area network, and others, including any combination of these.

[0201] Computing device 1600 is operable to register and authenticate users (using a login, unique identifier, and password for example) prior to providing access to applications, a local network, network resources, other networks and network security devices. Computing devices 1600 may serve one user or multiple users.Other Implementation Details

[0202] The following discussion provides many example embodiments. Although each embodiment represents a single combination of inventive elements, other examples may include all possible combinations of the disclosed elements. Thus if one embodiment comprises elementsA, B, and C, and a second embodiment comprises elements B and D, other remaining combinations of A, B, C, or D, may also be used.

[0203] Although terms such as “maximize”, “minimize” and “optimize” may be used in the present disclosure, it should be understood that such term may be used to refer to improvements, tuning and refinements which may not be strictly limited to maximal, minimal or optimal.

[0204] The term “connected” or "coupled to" may include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements).

[0205] The term “substantially” as used herein may be applied to modify any quantitative representation which could permissibly vary without resulting in a change in the basic function to which it is related. For example, a drive shaft as disclosed herein having a circular transverse cross-section may permissibly have a somewhat non-circular cross-section within the scope of the invention if its rotational driving capability is not materially altered.

[0206] Although the embodiments have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope as defined by the appended claims.

[0207] Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

[0208] As can be understood, the examples described above and illustrated are intended to be exemplary only. The scope is indicated by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A device for sample analysis, the device comprising: a movement grid comprising a top layer and a bottom layer, the bottom layer comprising a dielectric layer coated with a bottom hydrophobic layer, the top layer comprising a conductive top plate coated with a top hydrophobic layer, the top layer and the bottom layer defining a cavity, wherein a plurality of digital microfluidic (DMF) electrodes are configured to selectively actuate regions of the dielectric layer to move a sample droplet within the cavity between regions corresponding to each of the plurality of DMF electrodes via electrowetting-on-dielectric forces; at least one sensor configured to measure the sample droplet; and a bridge extending between at least one of the DMF electrodes and the at least one sensor to facilitate movement of the sample droplet to the at least one sensor; wherein the device is configured to move the sample droplet through the movement grid and from the movement grid to the at least one sensor via the bridge.

2. The device of claim 1 , wherein the bridge includes a hydrophilic coating applied to at least part of the at least one of the DMF electrodes and at least part of the at least one sensor.

3. The device of claim 1 , wherein the bridge includes a hydrophilic polymer matrix or surfactant.

4. The device of claim 1 , wherein the bridge includes a membrane formed of a dried hydrogel.

5. The device of claim 1 , wherein the bridge forms a hydrophilic surface above at least a portion of the movement grid.

6. A device for sample analysis, the device comprising: a movement grid comprising a top layer and a bottom layer, the bottom layer comprising a dielectric layer coated with a bottom hydrophobic layer, the top layer comprising a conductive top plate coated with a top hydrophobic layer, the top layer and the bottom layer defining a cavity, wherein a plurality of digital microfluidic (DMF) electrodes are configured to selectively actuate regions of the dielectric layer to move a sample droplet within the cavity between regionscorresponding to each of the plurality of DMF electrodes via electrowetting-on-dielectric forces; and at least one sensor configured to measure the sample droplet; wherein the device is configured to move the sample droplet through the movement grid and to the at least one sensor.

7. The device for sample analysis of claim 6, wherein the movement grid is disposed on a printed circuit board and the at least one sensor is disposed in a cavity of the printed circuit board.

8. The device for sample analysis of claim 6, wherein the at least one sensor is disposed on a printed circuit board and the at least one sensor includes an electrode with a via-in-pad.

9. The device for sample analysis of claim 6, wherein the at least one sensor includes an electrode pad and a wire extending from a first location on the electrode pad to a second location on the electrode pad to form a loop.

10. The device for sample analysis of claim 9, wherein the wire is wire-bonded to the electrode pad.11 . The device for sample analysis of claim 9, wherein the wire is formed of gold.

12. The device for sample analysis of claim 6, wherein the device further includes: a controller to detect an unexpected increase in a signal from the at least one sensor.

13. The device for sample analysis of claim 12, wherein the unexpected increase is an unexpected increase in measured current.

14. The device for sample analysis of claim 12, wherein the controller is configured to generate an alert based on the signal.

15. The device for sample analysis of claim 12, wherein the controller is configured to deactivate the at least one sensor based on the signal.

16. The device for sample analysis of claim 6, wherein the device further includes:a controller to schedule timing of activation of the at least one sensor based on timing of activations of the DMF electrodes.

17. The device for sample analysis of claim 16, wherein the controller schedules timing of activation of the at least one sensor to be interleaved with timing of activations of the DMF electrodes.

18. The device for sample analysis of claim 6, wherein the device further includes: a controller to monitor movement of the sample droplet from the movement grid to the at least one sensor.

19. The device for sample analysis of claim 18, wherein the controller performs at least one pilot assay prior to a primary assay.

20. The device for sample analysis of claim 19, wherein the controller causes the at least one sensor to activate in a first voltage range for the at least one pilot assay and to activate in a second voltage range higher than the first voltage range for the primary assay.

21. The device for sample analysis of claim 19, wherein the controller causes the at least one sensor to activate in a first voltage range for the at least one pilot assay and to activate in a second voltage range lower than the first voltage range for the primary assay.

22. The device for sample analysis of claim 6, wherein the at least one sensor includes a plurality of wires suspended over a given one of the DMF electrodes, each of the wires functioning as an electrode of the at least one sensor.

23. The device for sample analysis of claim 21 , wherein the device is configured to move the sample droplet away from the given one of the DMF electrodes.

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