Hydrophobic Cartridges for Digital Microfluidics

Abstract

Methods and compounds are disclosed for making and / or forming hydrophobic cartridges for use with digital microfluidic (DMF) devices. The hydrophobicity of the DMF cartridge may be improved by mixing an effective amount of one or more fluorinated surfactants with the polymer or polycarbonate resin used to form the cartridge. A method for preparing a molding compound for use in a DMF cartridge may include heating a compound of polycarbonate and fluorinated surfactant for a predetermined period of time.

Description

[Technical Field]

[0001] Priority claims This patent application claims priority to U.S. Provisional Patent Application No. 63 / 350,618, "HYDROPHOBIC CARTRIDGE FOR DIGITAL MICROFLUIDICS," filed June 9, 2022, which is incorporated by reference in its entirety.

[0002] INCORPORATION BY REFERENCE All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

[0003] Field FIELD OF THE DISCLOSURE The present disclosure relates to digital microfluidic devices and related fluid manipulation and extraction devices and methods for making the same. [Background technology]

[0004] background Digital microfluidics (DMF) is a powerful technique for the simple and precise manipulation of microscale fluid droplets. DMF is rapidly gaining popularity for chemical, biological, and medical applications due to its direct control of multiple reagents (no pumps, valves, or tubing required); its easy handling of both solids and liquids (no channels to clog); and its compatibility with difficult reagents (e.g., organic solvents, corrosive chemicals) due to the chemical inertness of the hydrophobic surfaces (typically treated with one or more hydrophobic coatings) that come into contact with the fluid droplets. Conventional DMF devices use relatively large electric fields selectively applied to electrode arrays to manipulate droplets. Generating and controlling these fields requires specialized and complex circuitry capable of withstanding relatively high voltages.

[0005] However, hydrophobic coatings must be applied through additional processing steps. Therefore, there is a need for hydrophobic surfaces that can be obtained with fewer processing steps. Summary of the Invention

[0006] Summary of the Disclosure Described and disclosed herein are methods and components for making and / or forming hydrophobic cartridges, such as, but not limited to, for use with any digital microfluidic (DMF) device. The hydrophobicity of the DMF cartridge may be enhanced by mixing a fluorinated surfactant with the polymer or polycarbonate resin used to form the DMF cartridge.

[0007] For example, described herein is a microfluidics cartridge comprising: a first plate having a first side and a second side; and a second plate, the first plate and the second plate being fixed opposite and parallel to one another with an air gap therebetween; and further wherein at least the first plate comprises an injection molding compound including polycarbonate and an effective amount of a fluorinated surfactant to increase the hydrophobicity of the first plate.

[0008] Generally, any of these cartridges may be a digital microfluidics (DMF) cartridge. For example, the cartridge may be for use with a DMF device and may include: a first (e.g., top) plate having a first side and a second side; a ground electrode disposed on the first side of the top plate; a second (e.g., bottom) plate, at least the top and bottom plates comprising an injection molding compound including polycarbonate and an effective amount of a fluorinated surfactant to increase the hydrophobicity of the top and bottom plates; and a frame configured to separate the top plate from the bottom plate to form an air gap therebetween, with the first side of the top plate facing the frame.

[0009] In any of the cartridges disclosed herein, the effective amount of fluorinated surfactant may be about 0.4% by weight of the polycarbonate. In any of the present cartridges, the fluorinated surfactant may be configured to bloom on the surfaces of the top and bottom plates. Further, in any of the cartridges disclosed herein, the fluorinated surfactant may be configured to increase the contact angle of deionized water with the top and bottom plates to greater than about 90 degrees.

[0010] In any of the cartridges disclosed herein, the fluorinated surfactant is trifluoroethyl methacrylate (TFMA). Additionally, the injection molding compound may further include a colorant in an amount of about 4% by weight of the polycarbonate. The colorant may be Clariant Mevopur NC7M820049.

[0011] In any of the cartridges disclosed herein, the ground electrode may be disposed on a surface of the top plate. Further, in any of the present cartridges, the ground electrode may be formed from an opaque material, a conductive ink, silver nanoparticles, or a combination thereof.

[0012] In any of the cartridges disclosed herein, the polycarbonate may be a medical-grade polycarbonate resin.In any of the cartridges disclosed herein, the fluorinated surfactant is Cytonix FluoroPel TFMA-6.

[0013] An exemplary method for preparing a hydrophobic injection molding compound for use in a cartridge device is disclosed. The exemplary method may include grinding a fluorinated surfactant into a powder; combining the fluorinated surfactant and a plurality of polycarbonate pellets together to form a compound; actively mixing the compound for at least 5 minutes; and, after active mixing, heating the compound to about 115 degrees Celsius for at least 4 hours.

[0014] In any of the methods described herein, the fluorinated surfactant may be in an amount of about 0.4% by weight of the plurality of polycarbonate pellets. Additionally, any of the methods may include adding a colorant to the compound in an amount of about 4% by weight of the plurality of polycarbonate pellets, where the actively mixing step further includes actively mixing the colorant with the plurality of polycarbonate pellets. The colorant may be Clariant Mevopur NC7M820049. In any of the methods described herein, the colorant may be added prior to the step of heating the compound.

[0015] In any of the methods described herein, the fluorinated surfactant may be trifluoroethyl methacrylate (TFMA). In any of the methods described herein, the fluorinated surfactant may be Cytonix FluoroPel TFMA-6.

[0016] In any of the present methods, the plurality of polycarbonate pellets may be medical-grade polycarbonate pellets. Further, in any of the present methods, the fluorinated surfactant may be a dry melt hydrophobic additive. In any of the methods described herein, the step of actively mixing the compound may occur at ambient temperature.

[0017] Another exemplary method may include receiving a compound of a fluorinated surfactant and polycarbonate pellets; heating and controlling the temperature of the compound to a temperature of about 250 degrees Celsius; and injecting the compound into an injection mold. In any of the methods described herein, the fluorinated surfactant may be in an amount of about 0.4% by weight of the polycarbonate pellets. Further, in any of the methods, the fluorinated surfactant may be trifluoroethyl methacrylate (TFMA).

[0018] In any of the methods described herein, the compound may include a colorant in an amount of about 4% by weight of the polycarbonate pellets. Further, the colorant may be Clariant Mevopur NC7M820049.

[0019] Any of the methods described herein may further include aging the cartridge for a period of two days or more after injection and before using the cartridge. In any of the methods, the polycarbonate pellets are medical-grade polycarbonate pellets. Further, the fluorinated surfactant may be a dry-melt hydrophobic additive. In any of the methods described herein, the compound may be heated to a temperature of about 115 degrees Celsius for a period of about four hours before receiving.

[0020] All methods and apparatus described herein, in any combination, are contemplated herein and may be used to realize the benefits as described herein. [Brief explanation of the drawings]

[0021] A better understanding of the features and advantages of the methods and apparatus described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments and the accompanying drawings.

[0022] [Figure 1] 1 is a flow chart depicting an exemplary method for preparing a compound for use in manufacturing a cartridge for use with any microfluidic device. [Figure 2] 1 is a flowchart depicting an exemplary method for injection molding an article for use with a microfluidics device. [Figure 3] FIG. 1 shows an exploded view of a simplified representation of a microfluidics cartridge. [Figure 4] 1 shows an exploded view of another exemplary microfluidics cartridge. [Figure 5] 1 shows three different exemplary images showing the contact angle of deionized water with a conventional polymer or polycarbonate resin. [Figure 6]1 shows three different exemplary images showing the contact angle of deionized water with a polymer or polycarbonate resin similar to the formulation described with respect to FIG. 1 (e.g., a formulation including TFMA). DETAILED DESCRIPTION OF THE INVENTION

[0023] Detailed Description Disclosed are methods and compounds for making and / or forming hydrophobic cartridges for use with any microfluidic device. The hydrophobicity of the microfluidic cartridge may be enhanced by mixing one or more fluorinated surfactants with a polymer or polycarbonate resin, followed by heating the resulting compound for use in an injection molding process.

[0024] FIG. 1 is a flow chart depicting an exemplary method 100 for preparing a compound for use in manufacturing a cartridge for use with any microfluidics device, including, but not limited to, a digital microfluidics (DMF) device. While injection molding is described herein, any other viable method may be used to form the cartridge. Traditional injection molding techniques may use a polymer as the primary material. The hydrophobicity of the primary material may be increased by the addition of a fluorinated surfactant. Additionally, one or more colorants may also be added to the primary material. The colorant does not adversely affect the hydrophobicity but allows for a visually appealing color to the cartridge.

[0025] The method 100 may begin at block 110, where the fluorinated surfactant is milled. In some embodiments, the fluorinated surfactant may be in the form of pellets. In other embodiments, the fluorinated surfactant may have an irregular (e.g., non-uniform) size and shape. Thus, the milling step may provide a fluorinated surfactant of a more uniform size and shape. This uniform size and shape may allow for a more even distribution of the surfactant in the base material. In some embodiments, the fluorinated surfactant may be milled into a fine powder.

[0026] In some variations, the fluorinated surfactant may be trifluoroethyl methacrylate (TFMA). One non-limiting example of TFMA is FluroPel TFMA-6 by Cytonix LLC. Other TFMA surfactants are possible. In some embodiments, TFMA may be a dry melt hydrophobic additive.

[0027] Next, in block 120, the components of the injection molding material are combined. The components of the injection molding material may include a primary material, a fluorinated surfactant, and (optionally) a colorant. The amount of each component of the injection molding material may be determined relative to the weight of the primary material to produce a consistent product with uniform hydrophobic properties.

[0028] The primary material may be any polymer or polymer-like material suitable for injection molding. In some embodiments, the primary material may be a polycarbonate resin. One non-limiting example of a polycarbonate resin is Makrolon 2458 resin. In some variations, the polycarbonate resin may be any viable medical-grade polycarbonate resin. The colorant may be any viable colorant compatible with the primary material and the fluorinated surfactant. One exemplary colorant is Clariant Mevopur NC7M820049.

[0029] The amount of fluorinated surfactant may be about 0.4% by weight based on the weight of the primary material. In some embodiments, about 0.4% by weight based on the weight of the primary material may be an effective amount of fluorinated surfactant to increase the hydrophobicity of cartridges formed from such compounds. However, in some variations, the effective amount of fluorinated surfactant used may be more or less than 0.4% by weight of the primary material.

[0030] The amount of colorant may be about 4% by weight based on the weight of the primary material. In some embodiments, about 4% by weight based on the weight of the primary material may be an effective amount of colorant to color a cartridge formed from such a compound. In some variations, the effective amount of colorant used may be more or less than 4% by weight of the primary material.

[0031] Next, in block 130, the ingredients are actively mixed. For example, the ingredients mentioned in block 120 may be mixed for at least a minimum period of time. An example of a minimum period of time is 5 minutes, although any other feasible period of time that evenly distributes the ingredients of the compound may be used. In some variations, mixing may occur at ambient or room temperature. An example of ambient or room temperature is 10 degrees Celsius, although other ambient temperatures may be used.

[0032] Next, the ingredients are heated at block 140. In some embodiments, the ingredients may be heated at a controlled temperature for a minimum time. For example, the minimum time period for heating the ingredients may be about 4 hours, although other minimum time periods may be used. The controlled temperature may be about 115 degrees Celsius, although other controlled temperatures may be used in some other variations.

[0033] 2 is a flowchart depicting an exemplary method 200 for injection molding an article for use with an apparatus. Method 200 may begin at block 210, where an injection molding compound (e.g., the mixed components of FIG. 1) is received. For example, the compound described with respect to FIG. 1 (e.g., a polymer, a fluorinated surfactant in an amount of about 0.4% by weight of the polymer, and a colorant in an amount of about 4% by weight of the polymer) may be received by a hopper or any suitable injection molding equipment.

[0034] Next, at block 220, the injection molding compound is heated. In some embodiments, the injection molding compound may be heated to approximately 250 degrees Celsius. In some variations, the injection molding compound may be heated to temperatures above 250 degrees Celsius, but only for a limited period of time. In some embodiments, heating the injection molding compound to a temperature of approximately 250 degrees Celsius may be sufficient to liquefy the molding compound, but not high enough to destroy or adversely affect the hydrophobic properties of the TFMA contained in the compound.

[0035] Next, at block 230, an injection molding compound is injected into the mold. In some embodiments, the mold may be for all or part of a cartridge. By molding all or part of a DMF cartridge with a TFMA-containing compound, each cartridge may have increased hydrophobicity compared to a cartridge made without TFMA.

[0036] In some variations, the injection-molded part may be aged for a predetermined period of time after injection into the mold. In some examples, the predetermined period of time may be as short as two days, and in some cases up to ten days after injection molding. Waiting the predetermined period of time may allow the TFMA to "bloom" onto the exterior surface of the injection-molded part. The aging process may allow the surface of the injection-molded part to develop maximum hydrophobicity.

[0037] One or more components of a cartridge for use with any viable microfluidics device may be injection molded as described with respect to Figure 2 using an injection molding compound as described with respect to Figure 1. The resulting cartridge may have one or more hydrophobic surfaces, which may enhance the performance of the associated cartridge, for example, by reducing surface fouling.

[0038] 3 shows an exploded view of a simplified representation of cartridge 300 configured as a DMF cartridge. Exemplary DMF cartridges and devices are described in commonly assigned U.S. patent application Ser. No. 16 / 259,984, filed Jan. 28, 2019, now U.S. Pat. No. 11,311,882, the entire disclosure of which is incorporated herein by reference.

[0039] DMF cartridge 300 may include an upper frame 310, a top plate 320, a tensioning frame 330, a bottom plate 340, and a base 350. Other cartridges 300 may include more or fewer components than those described in FIG. 3. In some variations, the components of DMF cartridge 300 may be arranged differently than those shown and described in FIG. 3.

[0040] A top plate 320 may be coupled to the upper frame 310. In some variations, the top plate 320 may include a conductive material that can function as an electrode (e.g., a ground electrode). In some embodiments, the electrode may be formed from an opaque material, conductive ink, and / or silver nanoparticles. The combination of the upper frame 310 and the top plate 320 may be coupled to a tensioning frame 330. A bottom plate 340 may also be coupled to the tensioning frame 330. In some embodiments, the bottom plate 340 may be thin and relatively flexible. In some variations, the tensioning frame 330 may hold the thin, flexible bottom plate 340 flat by providing a uniform, outward tension (relative to the center of the bottom plate 340) to the bottom plate 340.

[0041] The tensioning frame 330 may be mounted (coupled) to a base 350. The base 350 may facilitate temporary mounting and / or attachment of the DMF cartridge 300 to a DMF device (not shown). The tensioning frame 330 may provide or form an air gap 335 between the top plate 320 and the bottom plate 340. Additionally, one or more openings may be provided in the top plate 320 and / or bottom plate 340 to allow a user to introduce analytes, reagents, and the like into the air gap 335. Analytes, reagents, and other chemicals may be used to provide an analysis or assay of any viable analyte.

[0042] One or more components of cartridge 300 may be formed from the compound material described with respect to FIG. 1 and may be injection molded as described with respect to FIG. 2. Thus, the surfaces of the components of DMF cartridge 300 may be hydrophobic. In particular, top plate 320 and bottom plate 340 may be hydrophobic, which may reduce surface fouling associated with the operation of DMF within air gap 335. Additionally, DMF cartridge 300 may include one or more openings to allow the introduction of analytes, reagents, liquids, and the like into air gap 335. Any of these devices may include an air gap between the first and second plates. The air gap may be configured to hold droplets between the plates, for example, droplets contacting both plates or at least one plate (e.g., the bottom plate). The air gap may be about 0.1 mm to about 7 mm (for example, about 0.2 mm to about 5 mm, about 0.2 mm to about 4 mm, about 0.3 mm to about 5 mm, about 0.2 mm to about 3.5 mm, about 0.2 mm to about 3 mm, etc.).

[0043] 4 shows an exploded view of another exemplary DMF cartridge 400. DMF cartridge 400 may include a body 410, a top plate 420, a frame 430, and a bottom plate 440. Body 410 may include one or more microfluidic channels and / or chambers (not shown) for delivering or receiving fluids into / out of an air gap (not shown) bounded between top plate 420 and bottom plate 440. In some embodiments, multiple connectors 415 may allow for the introduction of solvents, reagents, analytes, etc. into the air gap of DMF cartridge 400.

[0044] In some embodiments, one or more reservoirs 416 may be attached to body 410. Reservoirs 416 may be used to store reagents or other solutions that may be used during an analysis and / or assay. Additionally, one or more waste receptacles 417 may also be attached to body 410. Waste receptacles 417 may be used to receive and / or store waste liquids generated during an analysis and / or assay. For example, used reagents or cleaning by-products may be stored in waste receptacle 417. Body 410 may also include a protective film 418.

[0045] The top plate 420, frame 430, and bottom plate 440 may form an air gap of the DMF cartridge 400. In some embodiments, the top plate 420, frame 430, and bottom plate 440 may be formed from a compound material as described with respect to FIG. 1 and may be injection molded as described with respect to FIG. 2. Thus, the top plate 420, frame 430, and / or bottom plate 440 may be formed from a hydrophobic material. Note that, for convenience, we refer to the top and bottom plates herein as "top" and "bottom" plates, but these may also be more accurately referred to as first and second plates herein and may be arranged in any orientation (e.g., top / bottom).

[0046] In some variations, the top plate 420 may include a conductive material that can function as an electrode (e.g., as a ground electrode). In some variations, the bottom plate 440 may be thin and flexible and may be held in tension by at least the frame 430.

[0047] Figure 5 shows three different example images showing the contact angle of deionized water with a conventional polymer or polycarbonate resin. The contact angle of deionized water can provide an indication of hydrophobicity. Generally, the higher the water contact angle, the more hydrophobic the polymer or polycarbonate resin.

[0048] In image 510, the first water droplet 511 has a left contact angle 512 of about 87.58 degrees, a right contact angle 513 of about 86.69 degrees, and an average contact angle of about 87.14 degrees. In image 520, the second water droplet 521 has a left contact angle 522 of about 88.94 degrees, a right contact angle 523 of about 88.93 degrees, and an average contact angle of about 88.94 degrees. In image 530, the third water droplet 531 has a left contact angle 532 of about 86.48 degrees, a right contact angle 533 of about 87.97 degrees, and an average contact angle of about 87.23 degrees. Thus, for a conventional polymer or polycarbonate resin, the average water contact angle is seen to be about 87.77 degrees.

[0049] FIG. 6 shows three different exemplary images showing the contact angle of deionized water with a polymer or polycarbonate resin similar to the formulations described with respect to FIG. 1 (e.g., formulations including TFMA).

[0050] In image 610, a first small water droplet 611 has a left contact angle 612 of about 94.68 degrees, a right contact angle 613 of about 94.34 degrees, and an average contact angle of about 94.51 degrees. In image 620, a second small water droplet 621 has a left contact angle 622 of about 94.49 degrees, a right contact angle 623 of about 91.97 degrees, and an average contact angle of about 93.23 degrees. In image 630, a third small water droplet 631 has a left contact angle 632 of 95.46 degrees, a right contact angle 633 of 94.29 degrees, and an average contact angle of 94.88 degrees.

[0051] Therefore, the overall average water contact angle for deionized water in contact with a polymer or polycarbonate resin containing TFMA is about 94.20 degrees. This overall average water contact angle is greater than the overall average water contact angle for a conventional polymer or polycarbonate resin. Therefore, a polymer or polycarbonate resin containing TFMA may have a relatively high hydrophobicity.

[0052] It should be recognized that all combinations of the concepts discussed above, and the additional concepts described in more detail below (provided such concepts are not mutually inconsistent), are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0053] The process parameters and sequence of steps described and / or illustrated herein are provided by way of example only and can be varied as desired. For example, although the steps illustrated and / or described herein may be shown or discussed in a particular order, the steps do not necessarily have to occur in the order illustrated or discussed. The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or may include additional steps in addition to those disclosed.

[0054] As used herein, when a feature or element is referred to as being "on" another feature or element, it may be directly on the other feature or element, or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It is also understood that when a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it may be directly connected, attached, or coupled to the other feature or element, or there may be intervening features or elements present. In contrast, when a feature or element is referred to as being "directly connected," "directly attached," or "directly coupled" to another feature or element, there are no intervening features or elements present. Features and elements described or illustrated with respect to one embodiment may apply to other embodiments as well. Those skilled in the art will also recognize that a reference to a structure or feature being "adjacent" to another feature may have portions that overlap or underlie the adjacent feature.

[0055] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. For example, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It is further understood that as used herein, the terms "comprises" and / or "comprising" specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ."

[0056] Spatial relationship terms such as "under," "below," "lower," "over," and "upper" may be used herein for ease of description in describing the relationship of one element or feature to another element or feature, as illustrated in the figures. It is understood that the spatial relationship terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures were inverted, an element described as being "under" or "beneath" another element or feature would be oriented "over" that other element or feature. Thus, the exemplary term "under" can encompass both an above and below orientation. The device may be otherwise oriented (rotated 90 degrees or to other orientations), and the spatial relationship descriptors herein would be interpreted accordingly. Similarly, terms such as "upwardly," "downwardly," "vertical," and "horizontal" are used herein for descriptive purposes only, unless specifically indicated otherwise.

[0057] Although the terms "first" and "second" may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another. Thus, a first feature / element described below may be referred to as a second feature / element, and similarly, a second feature / element described below may be referred to as a first feature / element, without departing from the teachings of the present invention.

[0058] Throughout this specification and the appended claims, unless the context requires otherwise, the word "comprise," and variations such as "comprises" and "comprising," mean that various components may be used together in methods and articles (e.g., compositions and apparatuses, including devices and methods). For example, the term "comprising" is understood to imply the inclusion of any stated element or step, but not the exclusion of any other elements or steps.

[0059] Generally, any of the apparatus and methods described herein should be understood as being inclusive, although alternatively, all or a subset of the components and / or steps may be exclusive and may be expressed as "consisting of," or alternatively, "consisting essentially of," various components, steps, subcomponents, or substeps.

[0060] All numbers used in this specification and claims, including those used in the examples, unless otherwise expressly stated, may be read as if preceded by the term "about" or "approximately," even if the term does not explicitly appear. The phrase "about" or "approximately," when describing magnitude and / or position, may be used to indicate that the described value and / or position is within a reasonably expected range of value and / or position. For example, a numerical value may have a value that is + / - 0.1% of the stated value (or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical value given herein should be understood to include about or approximately that value unless the context indicates otherwise. For example, if the value "10" is disclosed, "about 10" is also disclosed. Any numerical range recited herein is intended to include all subranges subsumed therein. It is also understood that when a value is disclosed, "less than or equal to the value," "greater than or equal to the value," and possible ranges therebetween, as would be appropriately understood by one of ordinary skill in the art, are also disclosed. For example, if a value "X" is disclosed, "less than or equal to X" and "greater than or equal to X" (e.g., where X is a numeric value) are also disclosed. It is also understood that throughout this application, data is provided in a number of different formats; and this data represents endpoints and starting points, as well as ranges, for any combination of the data points.For example, if a particular data point "10" and a particular data point "15" are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and even between 10 and 15 are also considered disclosed. It is also understood that every unit between the two specified units is also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0061] While various illustrative embodiments have been described above, any of numerous modifications may be made to the various embodiments without departing from the scope of the invention as set forth by the claims. For example, the order in which various steps of the described methods are performed may often be changed in alternative embodiments, and in other alternative embodiments, one or more steps of the methods may be skipped altogether. Optional features of the various embodiments of the devices and systems may be included in some embodiments and not included in other embodiments. Accordingly, the foregoing description has been provided primarily for illustrative purposes and should not be construed as limiting the scope of the invention as set forth in the claims.

[0062] The examples and illustrations contained herein illustrate, by way of illustration and not limitation, specific modes in which the present subject matter may be practiced. As noted, other modes may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Although such modes of the present subject matter may be individually or collectively referred to herein by the term "invention," this is for convenience only and is not intended to intentionally limit the scope of the present application to any single invention or inventive concept, if more than one invention or inventive concept is actually disclosed. Thus, while specific modes are illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific mode. The present disclosure is intended to cover any and all adaptations or variations of the various modes. Combinations of the above-described modes and other modes not specifically described herein will be apparent to one of skill in the art upon reviewing the foregoing description.

Claims

1. a first plate having a first side and a second side; and Second Plate Equipped with the first plate and the second plate are fixed opposite and parallel to one another with an air gap therebetween; further comprising at least the first plate comprising an injection molding compound comprising polycarbonate and an effective amount of a fluorinated surfactant to increase the hydrophobicity of the first plate; Microfluidics cartridge.

2. 10. The cartridge of claim 1, wherein the effective amount of the fluorinated surfactant is about 0.4% by weight of the polycarbonate.

3. 3. The cartridge of claim 1 or 2, wherein the fluorinated surfactant is configured to bloom on the surface of the first side of the plate within the air gap.

4. 4. The cartridge of claim 1, wherein the fluorinated surfactant is configured to increase the contact angle of deionized water to greater than about 90 degrees with respect to the top and bottom plates.

5. The cartridge of any one of claims 1 to 4, wherein the fluorinated surfactant is trifluoroethyl methacrylate (TFMA).

6. 6. The cartridge of claim 1, wherein the injection molding compound further comprises a colorant in an amount of about 4% by weight of the polycarbonate.

7. 7. The cartridge of claim 6, wherein the colorant is Clariant Mevopur NC7M820049.

8. The cartridge of any one of claims 1 to 7, wherein the fluorinated surfactant is configured to increase the hydrophobicity of the first plate.

9. 9. The cartridge of any one of claims 1 to 8, wherein the polycarbonate is a medical grade polycarbonate resin.

10. The cartridge of any one of claims 1 to 9, wherein the fluorinated surfactant is Cytonix FluoroPel TFMA-6.

11. a top plate having a first side and a second side; a ground electrode disposed on the first side of the top plate; A bottom plate, wherein at least the top plate and the bottom plate are: Polycarbonate and an effective amount of a fluorinated surfactant to increase the hydrophobicity of the top plate and the bottom plate; the bottom plate comprising an injection molding compound comprising: a frame configured to separate the top plate from the bottom plate to form an air gap therebetween, the first side of the top plate being oriented toward the frame; 1. A cartridge for use with a digital microfluidics (DMF) device, comprising:

12. 12. The cartridge of claim 11, wherein the effective amount of the fluorinated surfactant is about 0.4% by weight of the polycarbonate.

13. 12. The cartridge of claim 11, wherein the fluorinated surfactant is configured to bloom onto the surfaces of the top and bottom plates.

14. 12. The cartridge of claim 11, wherein the fluorinated surfactant is configured to increase the contact angle of deionized water to greater than about 90 degrees with the top and bottom plates.

15. 12. The cartridge of claim 11, wherein the fluorinated surfactant is trifluoroethyl methacrylate (TFMA).

16. 12. The cartridge of claim 11, wherein the injection molding compound further comprises a colorant in an amount of about 4% by weight of the polycarbonate.

17. 17. The cartridge of claim 16, wherein the colorant is Clariant Mevopur NC7M820049.

18. 12. The cartridge of claim 11, wherein the fluorinated surfactant is configured to increase the hydrophobicity of the top plate and the bottom plate.

19. The cartridge of claim 11 , wherein the ground electrode is disposed on a surface of the top plate.

20. 12. The cartridge of claim 11, wherein the ground electrode is formed from an opaque material, a conductive ink, silver nanoparticles, or a combination thereof.

21. 12. The cartridge of claim 11, wherein the polycarbonate is a medical grade polycarbonate resin.

22. 12. The cartridge of claim 11, wherein the fluorinated surfactant is Cytonix FluoroPel TFMA-6.

23. grinding the fluorinated surfactant into a powder; forming a compound by combining together the fluorinated surfactant and a plurality of polycarbonate pellets; actively mixing the compound for at least 5 minutes; and After active mixing, heating the compound to about 115 degrees Celsius for at least four hours.

1. A method for preparing a hydrophobic injection molding compound for use in a cartridge for a digital microfluidics (DMF) device, comprising:

24. 24. The method of claim 23, wherein the fluorinated surfactant is in an amount of about 0.4% by weight of the plurality of polycarbonate pellets.

25. 24. The method of claim 23, further comprising adding a colorant to the compound in an amount of about 4% by weight of the plurality of polycarbonate pellets, and wherein actively mixing further comprises actively mixing the colorant with the plurality of polycarbonate pellets.

26. 26. The method of claim 25, wherein the colorant is Clariant Mevopur NC7M820049.

27. 26. The method of claim 25, wherein the colorant is added prior to the step of heating the compound.

28. 24. The method of claim 23, wherein the fluorinated surfactant is trifluoroethyl methacrylate (TFMA).

29. 24. The method of claim 23, wherein the fluorinated surfactant is Cytonix FluoroPel TFMA-6.

30. 24. The method of claim 23, wherein the plurality of polycarbonate pellets are medical grade polycarbonate pellets.

31. 24. The method of claim 23, wherein the fluorinated surfactant is a dry melt hydrophobic additive.

32. 24. The method of claim 23, wherein the mixing occurs at ambient temperature.

33. receiving a compound of fluorinated surfactant and polycarbonate pellets; heating and controlling the temperature of the compound to a temperature of about 250 degrees Celsius; and Injecting the compound into an injection mold.

1. A method of making a cartridge for use with a digital microfluidics (DMF) device, comprising:

34. 34. The method of claim 33, wherein the fluorinated surfactant is in an amount of about 0.4% by weight of the polycarbonate pellets.

35. 34. The method of claim 33, wherein the fluorinated surfactant is trifluoroethyl methacrylate (TFMA).

36. 34. The method of claim 33, wherein the fluorinated surfactant is Cytonix FluoroPel TFMA-6.

37. 34. The method of claim 33, wherein the compound comprises a colorant in an amount of about 4% by weight of the polycarbonate pellets.

38. 38. The method of claim 37, wherein the colorant is Clariant Mevopur NC7M820049.

39. 34. The method of claim 33, further comprising aging the cartridge for a period of two or more days after ejection and before using the cartridge.

40. 34. The method of claim 33, wherein the polycarbonate pellets are medical grade polycarbonate pellets.

41. 34. The method of claim 33, wherein the fluorinated surfactant is a dry melt hydrophobic additive.

42. 34. The method of claim 33, wherein the compound is heated to a temperature of about 115 degrees Celsius for a period of about four hours before being received.

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