Background

[0001] Microfluidic devices are revolutionizing testing in the healthcare industry. Some microfluidic devices comprise digital microfluidic technology, which may employ circuitry to move fluids.

Brief Description of the Drawings

[0002] FIG. 1 A is a diagram including a side view schematically representing an example consumable microfluidic receptacle including electrodes formed on an anisotropic conductivity layer.

[0003] FIG. 1 B is a block diagram schematically representing an example external charge applicator.

[0004] FIGS. 2A and 2B are each a diagram including a side view schematically representing an example conductive element including an array of conductive particles.

[0005] FIG. 3 is a diagram including a side view schematically representing an example device and/or example method of controlling electrowetting movement via airborne charges deposited by a charge depositing unit in association with an example consumable microfluidic receptacle.

[0006] FIG. 4 is a diagram including a top plan view schematically representing an example consumable microfluidic receptacle.

[0007] FIG. 5 is a diagram including a side view schematically representing an example two-dimensional addressable charge depositing unit in charging relation to a portion of a consumable microfluidic receptacle. [0008] FIG. 6A is a diagram including a side view schematically representing an example electrode control element.

[0009] FIG. 6B is a diagram including a side view schematically representing an example electrode control element in releasable contact with an example consumable microfluidic receptacle.

[0010] FIGS. 7A-7B are each a diagram including a side view schematically representing an example alignment between electrodes of an electrode control array relative to electrodes of anisotropic conductivity layer of a consumable microfluidic receptacle.

[0011] FIG. 8 is a diagram including an isometric view schematically representing an example two-dimensional array of individually controllable electrodes, prior to releasable contact relative to, a portion of a consumable microfluidic receptacle.

[0012] FIG. 9 is a diagram including a side view schematically representing an example including a layer of electrodes sandwiched between two portions of anisotropic conductivity layer of a consumable microfluidic receptacle.

[0013] FIG. 10 is a diagram including a side view schematically representing an example anisotropic conductivity layer comprising an exterior surface portion supporting a layer of electrodes having varying sizes and/or shapes.

[0014] FIG. 1 1 is a diagram including a side view schematically representing an example including a layer of electrodes sandwiched between an anisotropic conductivity layer and a dielectric layer.

[0015] FIG. 12 is a diagram including a side view schematically representing an example consumable microfluidic receptacle including an anisotropic conductivity layer sandwiched between a first and second layers of electrodes.

[0016] FIG. 13A is a block diagram schematically representing an example fluid operations engine.

[0017] FIG. 13B is a block diagram schematically representing an example control portion.

[0018] FIG. 13C is a block diagram schematically representing an example user interface.

[0019] FIG. 14 is a flow diagram schematically representing an example method of applying charges to cause electrowetting movement of droplets. Detailed Description

[0020] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise.

[0021] The life sciences research and diagnostics industries are under pressure to reduce costs, increase throughput, and improve the utilization of samples. As a result, the instruments and tools used therein are moving from complex macrofluidic-based systems to simpler microfluidic-based technology. One class of such devices includes digital microfluidic devices.

[0022] Among other uses, these digital microfluidic devices may provide for molecular diagnostics which may help identify infectious diseases by performing operations on a sample of biological material. The molecular diagnostics may include nucleic acid testing, drug testing, neonatal testing, and other types of testing.

[0023] Among other functions, these digital microfluidic devices may handle fluid droplets. Each droplet may comprise a small, single generally spherical mass of fluid with the entire droplet being sized to be movable via electrowetting forces. In sharp contrast, dielectrophoresis may cause movement of particles within a fluid, rather than movement of an entire droplet of fluid.

[0024] Among other functions, these digital microfluidic devices provide for at least three main operations including moving, splitting, and merging the droplets. These operations can be used in various combinations to provide for more complex operations. For instance, mixing can be performed by repeating droplet moving or repeating droplet merging and splitting. [0025] In some of these microfluidic devices, movement of the fluid droplets within a passageway is controlled by an active electrode array which may create an electric field to induce movement of the fluid droplets. The active electrode array forms part of (i.e. is on-board) the microfluidic device such that the active electrode array cannot be separated from the portion defining the fluid droplet passageway. As further described below, these arrangements suffer from several drawbacks. Among other drawbacks, the incorporation of the active electrode array into the microfluidic device significantly increases the cost of manufacture, use, and handling after use (e.g. being discarded, recycling).

[0026] In contrast, at least some examples of the present disclosure are directed to a consumable microfluidic receptacle which is separate from an external charge applicator which applies charges to a portion of the consumable microfluidic receptacle. The charges create an electric field within the passageway of the microfluidic device to cause electrowetting movement of the fluid droplets. In one aspect, this example arrangement may dramatically reduce the cost of molecular diagnostics and/or other testing performed at least because the external charge applicator can be re-used over and over again, while the simpler consumable microfluidic receptacle may be manufactured, used, and/or disposed as a single use element at a significantly lower cost.

[0027] With this in mind, in at least some examples of the present disclosure, a consumable microfluidic receptacle may comprise a first plate electrically connectable to a ground element. A second plate is spaced apart from the first plate to define a passageway to receive a liquid droplet, wherein the second plate comprises a conductive-resistant matrix layer and a plurality of conductive paths spaced apart throughout the matrix layer and oriented perpendicular to a plane through which second plate extends. A plurality of electrodes is formed on, and spaced apart across, a first portion of the matrix layer with each electrode electrically coupled to at least one of the respective conductive paths. The electrodes are to receive charges from an external charge applicator to produce an electric field within the passageway to cause electrowetting movement of the liquid droplet. [0028] In some such examples, the electrodes may sometimes be referred to as charge-receiving electrodes. In one aspect, “charges” as used herein refers to ions (+/-) or free electrons.

[0029] Via such example arrangements, the charges received by the electrodes are conveyed via the conductive paths through the second plate to produce the electric field. In some examples, each conductive path comprises includes an elongate pattern of field-aligned, conductive particles.

[0030] In some such examples, each respective first and second plate may sometimes be referred to as a sheet, a wall, a portion, and the like.

[0031] Moreover, it will be apparent that in some examples, the consumable microfluidic receptacle may form part of and/or comprise a microfluidic device. In some examples, the consumable microfluidic receptacle may sometimes be referred to as a single use microfluidic receptacle, or as being a disposable microfluidic receptacle.

[0032] In some examples, the arrangement of the conductive-resistant matrix layer and plurality of conductive paths within the second plate may sometimes be referred as an anisotropic conductivity layer, which may facilitate migration of charges across the second plate by providing lower resistivity across or through the second plate and a higher lateral resistivity along the plane through which the second plate extends. Of course, the structure of the example anisotropic conductivity layer is further described below in much greater detail.

[0033] In some examples, the external charge applicator may comprise at least one of: a non-contact charge depositing unit to selectively emit airborne charges of a selectable polarity onto the respective electrodes; and an electrode control element comprising an array of individually controllable second electrodes of a circuitry substrate to selectively provide the charges upon releasable engagement against the plurality of respective electrodes. In some such examples, the circuitry substrate may comprise a printed circuit board or thin film transistor. Via these arrangements, the external charge applicator is to achieve and maintain a target voltage at the electrodes, i.e. the charge-receiving electrodes. This target voltage may comprise on the order of tens of Volts to hundreds of Volts. [0034] In some examples, the external charge applicator may apply the charges having a first polarity and/or an opposite second polarity, depending on whether the external charge applicator is to build charges on the plate or is to neutralize charges on the plate. The first polarity may be positive or negative depending on the particular goals, while the second polarity will be the opposite of the first polarity. In some examples, electrodes of the electrode control element may sometimes be referred to as control electrodes or as driving electrodes.

[0035] In some examples, the movement of droplets (caused by electrowetting forces) may occur between adjacent target positions along passageways within a microfluidic receptacle of a microfluidic device, with the target positions corresponding to locations at which the charges are directed from one of the example external charge applicators.

[0036] In some examples, the electrodes formed within or on (at least) the conductive-resistant matrix layer may enhance conveyance of charges through the second plate by counter-acting irregularities within or on the conductive- resistant matrix layer, along the conductive paths, and/or at an interface between the conductive-resistant matrix layer and the external charge applicator.

[0037] In particular, in instances in which the external charge applicator comprises an electrode control element (e.g. electrode array) brought into releasable contact with the conductive-matrix layer, irregular surface topography of the conductive-resistant matrix layer and/or of the respective electrodes of the electrode control array (of the external charge applicator) may cause poor surface contact between those respective elements. This poor surface contact, in turn, may inhibit application (e.g. transfer) of electrical charges from the external charge applicator to the second plate of the consumable microfluidic receptacle. This inhibition, in turn, may reduce the magnitude of charges deposited at the exterior surface of the second plate, which in turn would inhibit or diminish a magnitude of the voltage differential across the passageway. This diminished voltage differential would, in turn, reduce the electrowetting forces applied on the liquid droplet(s), which then may inhibit the intended operations of moving, splitting, merging, etc. This inhibition may, in turn, hamper the effectiveness of the molecular testing, diagnostics, etc. [0038] In one aspect, the irregular surface topography may comprise irregularities present as part of forming the conductive-resistant matrix layer and/or the conductive paths magnetically aligned therein. In another aspect, to the extent that the electrodes on the electrode control element are not planarized, then the contact surface of these electrodes may include irregular surface.

[0039] In other instances, poor transfer of the electrical charges (from the external charge applicator) to the conductive paths (within the conductive- resistant matrix layer) may be caused by debris present on the conductive paths, conductive-resistant layer, and/or on the electrodes of the active electrode array. [0040] The debris may cover a portion of the surface of the electrodes of the electrode control element and/or may cover a surface portion of the conductive- resistant matrix layer (and/or ends of the conductive paths). Accordingly, the debris may interfere with establishing robust, uniform contact between the surface of the electrodes of the electrode control element and surface portion of the conductive-resistant matrix layer (and/or ends of the conductive paths).

[0041] In some instances in which charges are applied from an addressable charge depositing unit as airborne charges, then debris present on the surface of the conductive-resistant matrix layer (and/or ends of the conductive paths) may interfere with reception of these airborne charges. This interference may, in turn, reduce uniformity and accuracy of depositing charges from the addressable charge depositing unit.

[0042] In some instances, during formation (e.g. magnetic alignment) of the conductive-resistant matrix layer and/or formation of the conductive paths within the conductive-resistant matrix layer, some of the bulk material (of the conductive- resistant matrix layer) and/or some of the conductive particles (which form the conductive paths) may remain and/or become bunched together resulting in the above-mentioned formation irregularities. This bunching may be of a shape and/or of a size, which inhibits conveyance of the electrical charges along and through the conductive paths.

[0043] Given these various ways in which irregularities from formation and/or from debris may interfere with the reception, transfer, and/or conveyance of charges received from an external charge applicator, at least some examples of the present disclosure include charge-receiving electrodes (different from the electrodes of the electrode control element) formed on a portion of the conductive- resistant matrix layer. In some such examples, these charge-receiving electrodes are of a size and/or a shape to be co-extensive with a plurality of conductive paths extending within the conductive-resistant matrix layer.

[0044] In one aspect, each charge-receiving electrode, or a group of these electrodes, extend in a plane which is generally parallel to, or generally the same as, the plane in which the conductive-resistant matrix layer extends.

[0045] Via these arrangements, the charge-receiving electrodes may act as current spreading elements or charge spreading elements, at least in the sense that upon charge(s) striking any portion of a particular electrode, the effect of the charge(s) are spread out along the entire (or substantially the entire) electrode. Accordingly, to the extent that debris or formation irregularities (in the conductive paths and/or conductive-resistant matrix layer) are co-extensive with a portion of a respective one of the charge-receiving electrodes, the distribution or spreading of the electrical effect of the received charges throughout the entire area of the charge-receiving electrode acts to effectively circumvent the debris and/or the formation irregularity so that the electrical effect of a significant portion of the intended charges effect is still conveyed, via the electrode, through the conductive paths electrically coupled to the particular electrode.

[0046] As further detailed below, such charge-receiving electrodes may be implemented in various configurations relative to the conductive-resistant matrix layer and/or the conductive paths to overcome the presence of debris and/or formation irregularities.

[0047] In some examples, the first portion of the matrix layer comprises an exterior surface portion facing the external charge source the electrodes are formed on, and spaced apart across, the exterior surface portion of the matrix layer, each first electrode electrically coupled relative to an end of at least one of the respective conductive paths.

[0048] In some examples, the first portion of the matrix layer comprises an interior surface portion facing the first plate, and the electrodes are formed on, and spaced apart across, the interior surface portion of the matrix layer, each first electrode electrically coupled relative to an end of at least one of the respective conductive paths.

[0049] In some examples, the first portion of the matrix layer comprises an interior surface portion and an exterior surface portion. The interior surface portion faces the first plate, wherein the electrodes comprise first electrodes formed on, and spaced apart across, the interior surface portion of the matrix layer, each first electrode electrically coupled relative to a second end of at least some of the respective conductive paths. The exterior surface portion faces the external charge applicator, wherein the electrodes comprise second electrodes formed on, and spaced apart across, the exterior surface portion of the matrix layer, each second electrode electrically coupled relative to an opposite first end of at least some of the respective conductive paths.

[0050] In some examples, the first portion of the matrix layer comprises a first layer and a second layer wherein the electrodes are sandwiched between the respective first and second layers of the matrix layer.

[0051] In some examples, a size and/or shape of at least some of the electrodes vary from one another. In some such examples, the size and/or shape of the electrodes (e.g. charge-receiving electrode) may be significantly less than a size and/or shape of a respective one of the single electrodes of an electrode control element which applies charges to the formed electrodes of the matrix layer. In some of these examples, the sizes and/or shapes may vary in a pseudo-random manner.

[0052] Conversely, in some examples a respective charge-receiving electrode (on the anisotropic conductivity layer) may be larger than a respective one of the electrodes of the electrode control element (e.g. active control electrode array), which may help ensure alignment and/or significant overlap between the formed electrodes and the control electrodes.

[0053] In some examples, the second plate comprises a dielectric layer in contact with the interior surface portion, facing the first plate, and further defining the passageway, and wherein the respective second electrodes are sandwiched between the dielectric layer and the interior surface portion of the matrix layer of the second plate. [0054] In some examples, a digital microfluidic assembly comprises a consumable microfluidic receptacle and an external charge applicator. The consumable microfluidic receptacle may comprise a fluid droplet passageway at least partially defined by an anisotropic conductivity first portion including a plurality of conductive paths spaced apart throughout the first portion and oriented perpendicular to a plane through which first portion extends; and a plurality of electrodes formed on, and spaced apart across, the first portion with each electrode electrically coupled to at least one of the respective conductive paths. The external charge applicator is removably positionable into charging relation to the plurality of electrodes.

[0055] In some such examples, the external charge applicator comprises at least one of: a non-contact charge depositing unit to selectively emit airborne charges of a selectable polarity onto the respective electrodes; and an electrode control element comprising an array of individually controllable second electrodes of a circuitry substrate to selectively transmit the charges upon releasable engagement against the plurality of respective electrodes.

[0056] In some examples, the consumable microfluidic receptacle comprises a first plate electrically connectable to a ground element and a second plate spaced apart from the first plate, wherein the second plate and the first plate define the liquid droplet passageway and the second plate comprises the anisotropic conductivity first portion.

[0057] Via such example arrangements, the consumable microfluidic receptacle (of a microfluidic device) may omit active control electrodes (e.g. electrically active electrodes) which would otherwise be used to cause microfluidic operations such as moving, merging, and/or splitting droplets within a microfluidic device. Moreover, by using an example external charge applicator to cause an electric field on a portion of the consumable microfluidic receptacle, the consumable microfluidic receptacle may omit inclusion of a printed circuit board and circuitry (e.g. active control circuitry) typically associated with digital microfluidic devices. This arrangement may significantly reduce the cost of the consumable microfluidic receptacle of the microfluidic device and/or significantly ease its recyclability. [0058] Moreover, because the consumable microfluidic receptacle omits such electrically active control electrodes (for causing electrowetting movement) and omits complex circuitry which is typically directly connected to the control electrodes via conductive traces, the example consumable microfluidic receptacle of the present disclosure is not limited by the limited space constraints typically arising from a one-to-one correspondence between control electrodes and the complex control circuitry. Absent such space constraints, a greater number of target positions along the passageways of the microfluidic receptacle may be used, which may increase the precision by which microfluidic operations are performed, with a resolution (e.g. number of target positions for a given area) of such target positions corresponding to the capabilities (e.g. resolution) that the example external charge applicator (e.g. non-contact addressable charge depositing unit or electrode control element) can deposit charges. By being able to re-use the example external charge applicator over-and-over again with a supply of disposable or consumable microfluidic receptacles, this example arrangement greatly reduces the overall, long term cost of using digital microfluidic devices while significantly conserving valuable electrically conductive materials.

[0059] In some examples, the consumable microfluidic receptacle may be used to perform microfluidic operations to implement a lateral flow assay and therefore may sometimes be referred to as a lateral flow device. In some examples, the consumable microfluidic receptacle also may be used for other types of devices, tests, assays which rely on or include digital microfluidic operations, such as moving, merging, splitting, etc. of droplets within internal passages within the microfluidic device.

[0060] These examples, and additional examples, are further described and illustrated below in association with at least FIGS. 1A-14.

[0061] FIG. 1 A is a diagram including a side view schematically representing an example arrangement 100 (and/or example method) for electrowetting movement of microfluidic droplets 129. In some examples, the arrangement 100 may comprise a consumable microfluidic receptacle 102. [0062] As shown in FIG. 1 A, the consumable microfluidic receptacle 102 comprises a first plate 1 10 and a second plate 120 spaced apart from the first plate 1 10, with the spacing between the respective plates 110, 120 sized to receive and allow movement of a liquid droplet 129, such as a polar liquid droplet (e.g. conducive droplet). In some examples, the consumable microfluidic receptacle may form a portion of a microfluidic device, and according sometimes may be referred to as a microfluidic device or portion thereof.

[0063] As shown in FIG. 1 A, in some examples each of the respective first and second plates 110 comprise an interior surface 1 1 1 , 121 , respectively, and each of the respective first and second plates 1 10, 120 comprise an exterior surface 1 12, 122, respectively. The first and second plates 1 10, 120 may sometimes be referred to as first and second plates 110, 120, respectively.

[0064] In some examples, at least the interior surface 1 1 1 , 121 of the respective plates 1 10, 120 may comprise a planar or substantially planar surface. However, it will be understood that the passageway 1 19 defined between the respective first and second plates 1 10, 120 may comprise side walls, which are omitted for illustrative simplicity. The passageway 1 19 may sometimes be referred to as a conduit, cavity, and the like.

[0065] It will be understood that the first and second plates 1 10, 120 may form part of, and/or be housed within a frame, such as the frame 305 of the microfluidic device 300 as later described in association with at least FIG. 4.

[0066] In some examples, the interior of the passageway 1 19 (between plates 1 10, 120) may comprise a filler such as a dielectric oil, while in some examples, the filler may comprise air. In some such examples, the filler may comprise other liquids which are immiscible and/or which are electrically passive relative to the droplet 129 and/or relative to the respective plates 1 10, 120. In some examples, the filler may affect the pulling forces (F), may resist droplet evaporation, and/or facilitate sliding of the droplet and maintaining droplet integrity.

[0067] In some examples, the distance (D1 ) between the respective plates 1 10, 120 may comprise between about 50 to about 500 micrometers, between about 100 to about 150 micrometers, or about 200 micrometers. In some examples, the droplet 129 may comprise a volume of about less than a microliter, such as between about 10 picoliters and about 30 microliters. However, it will be understood that in some examples, the consumable microfluidic device 102 is not strictly limited to such example volumes or dimensions.

[0068] In some examples, the first plate 110 may be grounded, i.e. electrically connected to a ground element 1 13, which is also later shown in other FIGS, such as element 1 13 in at least FIGS. 3 and 6B. In some examples, the first plate 110 may comprise a thickness (D4) of about 100 micrometers to about 3 millimeters, and may comprise a plastic or polymer material. In some examples, the first plate 1 10 may comprise a glass-coated, indium tin oxide (ITO). As noted later in association with at least FIG. 4, the thickness (D4) of first plate 1 10 may be implemented to accommodate fluid inlets (e.g. 321 A, 323A, etc. in FIG. 4), to house and/or integrate sensors into the first plate 110, and/or to provide structural strength. In some examples, the sensors may sense properties of the fluid droplets, among other information.

[0069] In some examples, the second plate 120 of the example microfluidic receptacle 100 may comprise a substrate 123, and in some examples, the substrate 123 may comprise an anisotropic conductivity layer 130, which is described below in detail.

[0070] In some examples, the second plate 120 also may comprise an array 170 of electrodes 172 formed on the anisotropic layer 130 in order to receive charges 264A from an external charge applicator (e.g. 190 in FIG. 1 B) to induce electric field (represented by arrow E) across the passageway 1 19 in induce electrowetting movement of droplet 129. The electrodes 172 may sometimes be referred to as charge-receiving electrodes 172.

[0071] Further details regarding such electrodes 172 are described below after providing further detail regarding the anisotropic conductivity layer 130. Meanwhile, further details regarding the deposit, reception, conveyance, etc. of charges 264A (FIG. 1 ), the electric field E, and the induced electrowetting movement is further described in association with at least FIGS. 3 and 6B. For instance, as further described later, in some examples the external charge applicator (e.g. 190 in FIG. 1 B) may be implemented as an example addressable charge depositing unit (280 in FIGS. 3, 5) or as an addressable electrode control element 1050 FIGS. 6A, 6B, in some examples.

[0072] In some examples, in general terms the anisotropic conductivity layer 130 acts to facilitate migration (i.e. conveyance of charges 264A) to a position at which the charges 264A contribute to forming an electric field E to induce electrowetting movement of the fluid droplet 129, as further describe later in association with at least FIG. 3.

[0073] With this in mind, as shown in FIG. 1A, in some examples the anisotropic conductivity layer 130 comprises a conductive-resistant medium 135 (e.g., conductive-resistant matrix layer, partially conductive matrix) within which an array 132 of conductive elements 134 is oriented generally perpendicular to the plane (P1 ) through which the entire anisotropic conductivity layer 130 generally extends. In some examples, the conductive-resistant medium 135 (e.g. matrix) may comprise a bulk resistivity of about 10 ¹¹ Ohm-cm to about 10 ¹⁶ Ohm-cm. In some examples, this bulk resistivity may sometimes be referred to as a lateral resistivity, which expresses a resistivity in an orientation along (or parallel to) plane P1. While FIG. 1 A provides a two-dimensional view, it will be understood from FIG. 1 A that this lateral resistivity extends in an X-Y orientation with the direction C corresponding the X orientation according to the X-Y-Z reference axes.

[0074] In some such examples, each conductive element 134 may comprise a resistivity in the B direction (e.g. perpendicular to the plane P1 ) of layer 130 to be less than 10 ⁵ ohm cm. In some such examples, each conductive element 134 may comprise a cross-sectional area of 1 micrometer squared, and a spacing (in the X-Y orientation) between adjacent conducive elements 134 of about 10 micrometers. In some examples, this resistivity in the B direction may be referred to as a vertical resistivity and/or as resistivity in a Z orientation according to the X-Y-Z reference axes.

[0075] Accordingly, in some examples, a resistivity (e.g. 10 ⁵ Ohm-cm) of each conductive element 134 extending in the B direction may comprise at least six orders of magnitude less than the bulk resistivity of the conductive-resistant medium 135 (e.g. at least 10 ¹¹ Ohm-cm) of layer 130. Stated in different terms, each conductive element 134 individually (and/or when considered collectively) may comprise a conductivity which is at least six orders of magnitude greater than a bulk conductivity of the conductive-resistant medium 135 of layer 130.

[0076] In some examples, an overall vertical resistivity (e.g. in the B direction) of the layer 130 takes into consideration both the bulk resistivity (at least 10 ¹¹ Ohm- cm) of conductive-resistant medium 135 and the resistivity (e.g. 10 ⁵ Ohm-cm) of the conductive elements 134 with one example overall vertical resistivity of layer 130 comprising less than about 10 ⁷ Ohm-cm.

[0077] In some examples, the resistant-conductive medium 135 of the layer 130 may comprise a plastic or polymeric materials, such as but not limited to, materials such as polypropylene, Nylon, polystyrene, polycarbonate, polyurethane, epoxies, or other plastic materials which are low cost and available in a wide range of conductivities. In some examples, a bulk conductivity (or bulk resistivity) within the desired range noted above may be implemented via mixing into the plastic material some conductive carbon molecules, carbon black pigments, carbon fibers, or carbon black crystal.

[0078] In some examples, the relative permittivity of the conductive-resistant medium 135 of the anisotropic layer 130 may be greater than about 20. In some examples, the relative permittivity may be greater than about 25, 30, 35, 40, 45 50, 55, 60, 65, 70, or 75. In some instances, the relative permittivity may sometimes be referred to as a dielectric constant. Among other attributes, providing such relative permittivity may result in a lower voltage drop across the second plate 120. In some examples, the relative permittivity of the second plate 120 in the direction of the plane P1 may comprise lower than about 10. In some examples, it may comprise about 3.

[0079] In comparison to the relatively high conductivity of the conductive resistant medium 135 perpendicular to the plane P1 (direction B), the abovenoted relatively low lateral conductivity (direction C) of the conductive resistant medium 135 may effectively force travel of the charges (applied by an external charge applicator 190 in FIG. 1 B) to travel primarily in a direction (B) perpendicular to the plane P1 , such that the electric field E acting within the passageway 1 19 (i.e. conduit) may comprise a target area (e.g. x-y dimensions) which are similar to the area (e.g. x-y dimensions) of each application of charges (from the external charge applicator) directed to a specific target position (e.g. T 1 , T2, etc.).

[0080] In some such examples, each above-noted target area corresponds to an area of a respective one of the charge-receiving electrodes 172.

[0081] As shown in FIG. 1 A, via the example anisotropic conductivity layer 130 of second plate 120, the conductive elements 134 are aligned generally parallel to each other, in a spaced apart relationship, in an orientation generally the same as the direction (arrow B) which the charges 264A at the exterior surface 124 (of second plate 120) are to travel through substrate 123 of second plate 120 to reach the interface 135 of substrate 322 with the dielectric layer 134. While the respective conductive elements 134 are shown as being oriented perpendicular to the plane P1 , it will be understood that in some examples the conductive elements 134 may be oriented at a slight angle (i.e. slanted) which not strictly perpendicular.

[0082] Moreover, in some examples, as shown in FIG. 2A, each respective conductive element 134 may comprise an array 137 of smaller conductive particles 138 which are aligned in an elongate pattern to approximate a linear element of the type shown as element 134 in FIG. 1 A. The array 138 of elements 138 (e.g. particles) represented in FIG. 2A may sometimes be referred to as a conductive path. In some examples, the conductive particles 138 may comprise metal beads with each bead ranging from 0.5 micrometers to about 5 micrometers in diameter (or a greatest cross-sectional dimension). In some such examples, these smaller conductive particles 138 may be aligned during formation of the anisotropic layer 130 via application of a magnetic field until the materials (e.g. conductive particles within the conductive-resistant medium) solidify into their final form approximating the configuration shown in FIGS. 2A-2B. In particular, after the magnetic particles become aligned under the influence of the magnetic field, the magnetic particles and the material of the conductive-resistant medium 135 may be subjected to radiation (e.g. heat or ultra-violet) to cause cross-linking which effectively locks or fixes the metal beads into the aligned location and orientation.

[0083] Consistent with the above-described examples, the elongate pattern formed by array 137 of conductive particles 138 (for each conductive element 134) may comprise a resistivity of less than 10 ⁵ Ohm-cm, in some examples. Further consistent with the above-described examples, this arrangement may reduce the overall resistivity (i.e. increase the overall conductivity) of layer 130 in the B direction (perpendicular to plane P1 ) to be less than about 10 ⁷ Ohm cm. In some examples, the conductive particles 138 may comprise conductive materials such as, but not limited to, iron or nickel. In some examples in which the conductive particles 138 are not in contact with each other, such particles 138 may be spaced apart by a distance F1 as shown in FIG. 2B, with such distances being on the order of a few nanometers in some examples. In some examples, the material (e.g. polymer) forming the conductive-resistant medium 135 of the anisotropic layer 130 of the second plate 120 is interposed between the respective conductive particles 138 of the array 137 (e.g. forming the elongate pattern) defining elements 134. In some such examples, because of this very small dimension F1 between at least some of the conductive particles 138, the conductive-resistant medium 135 interposed between the conductive particles 138 (and which would other exhibit a resistivity of at least on the order of 10 ¹¹ Ohm-cm in some examples) may comprise a conductive bridge (between adjacent particles 138) having a length less than about a micrometer and as such, may exhibit a much smaller resistivity which is several (e.g. 2, 3, or 4) orders of magnitude less than the resistivity otherwise exhibited by the conductive-resistant medium 135. Accordingly, even when some conductive resistant medium 135 is interspersed between some of the aligned conductive particles 138, the elongate pattern (e.g. array 137) of the conductive particles 138 still exhibits an overall conductivity perpendicular to the plane P1 (through which the second plate 120 extends) which comprises at least two orders of magnitude higher (e.g. greater) than the lateral conductivity along the plane P1 .

[0084] In some examples, because of the anisotropic conductivity arrangement defining at least a part of the substrate 123 of the second plate 120, the second plate 120 exhibits a response time which is substantially faster than if the substrate 123 were otherwise made primarily dielectric material or made of a partially conductive material without the conductive elements 134.

[0085] In one aspect, the anisotropic conductivity configuration of the substrate 123 of second plate 120 either may enable faster electrowetting movement of droplets 129 through passageway 1 19 due to higher electrical field on the droplet resulting in higher pulling forces and/or may permit use of thicker second plates (e.g. 120 in FIG. 1 A), as desired (i.e. increasing the thickness of second plate 120). In one aspect, providing a relative thick/thicker (substrate 123 of the) second plate 120 enables better structural strength, integrity, and/or better mechanical control of the gap between interior surface 1 11 of the first plate 110 and the interior surface 121 of the second plate 120. In some examples, the second plate 120 may comprise a thickness (D3) of about 30 micrometers to about 1000 micrometers. In some examples, the thickness (D3) may comprise about 30 micrometers to about 500 micrometers. In some examples, at least the substrate 123 of the second plate 120 may sometimes be referred to as a chargereceiving layer and sometimes may be referred to as an anisotropic conductivity layer.

[0086] In one aspect, the anisotropic conductivity configuration (e.g. layer 130) forming substrate 123 of second plate 120 in FIG. 1 A stands in sharp contrast to at least some anisotropic conductive films (ACF) which may resemble a tape structure and involve the application of high heat and high pressure, which in turn may negatively affect the overall structure of the consumable microfluidic receptacle, such as but not limited to, any sensitive sensor elements or circuitry within the first plate 110. Moreover, at least some anisotropic conductive films (ACF) may be relatively thin and/or flexible such that they are unsuitable to stand alone as a bottom plate of a microfluidic device because they may lack sufficient structural strength and durability.

[0087] With further reference to FIG. 1 A, as previously mentioned in some examples, the second plate 120 comprises an array 170 of electrodes 172 formed on the anisotropic conductivity layer 130 at exterior surface portion 122 of second plate 120. In some examples, the electrodes 172 comprise electrically conducive material and may be formed via printing the electrically conductive material directly onto the anisotropic conductivity layer 130. In some examples, the electrically conductive material may be printed via screen printing, inkjet printing, or flexographic printing. In some examples, the electrodes 172 may be formed via a thin-film vapor deposition process.

[0088] In some examples, each electrode 172 may comprise a generally uniform thickness and a sheet resistance of less than about 10 ³ Ohm per square. In some of these examples, the sheet resistance may comprise less than 10 ² Ohm per square. In some such examples, upon forming the electrodes 172 as a screen- printed layer of conductive carbon black material, the sheet resistance may comprise about 0.1 Ohm per square. In some examples, the screen printing may comprise a lithographic process utilizing a mask. In some examples, the conductive carbon black material may be obtained from Novacentrix of Austin, Texas.

[0089] As later noted in association with at least FIG. 10, in some examples the electrodes (e.g. 782 in FIG. 10) may be formed via a vapor deposition process, which may comprise sputtering or splattering, which in turn may produce a pseudo-random pattern of electrodes instead of a structured pattern of electrodes 172 in FIG. 1 A.

[0090] It will be understood that the above-noted sheet resistance may correspond to a resistivity of a thin-film structure divided by its thickness, and provides an indication of at least a lateral resistivity for each electrode 172, such as in a direction along or parallel to plane P2 in FIG. 1 A. The above-noted example relatively low values of sheet resistance indicate that the electrical effect of the deposited charges 264A electrodes 172 will rapidly spread (e.g. current spreading) laterally throughout the entire electrode 172. This rapid spreading, in turn, may facilitate overcoming blocked conductive pathways through (e.g. across) the anisotropic conductivity layer 130, as further described in much greater detail below in association with at least FIGS 3, 6B, and 9-12.

[0091] With further reference to FIG. 1 A, in some examples, each electrode 172 may comprise a thickness (H1 ) between about 50 nanometers to about 10 micrometers. [0092] In some examples, each electrode 172 may comprise a length L1 of about 150 micrometers to about 2 millimeters. In some examples, a spacing or gap G1 exists between adjacent electrodes of about 50 micrometers to about 150 micrometers, such as when an external charge applicator (e.g. 190 in FIG. 1 B) is implemented as an electrode control element (e.g. 500 in FIG. 6A) comprising a circuitry substrate made of a printed circuit board.

[0093] However, in some examples, the spacing or gap G1 between adjacent electrodes 172 may be significantly lower and may comprise about 3 micrometers to about 10 micrometers such as when the circuitry substrate of an electrode control element (e.g. 500 in FIG. 6A) comprises a thin film transistor (TFT) structure, which may utilize an example activation voltage of about 20 Volts to about 50 Volts.

[0094] It will be understood that these examples comprise general numerical ranges and that in some examples, the numerical examples of the length L1 and the gap G1 for electrodes 172 may be subject to further constraints such as, but not limited to, at least some examples in which the length (L1 ) of each chargereceiving electrode 172 is less than a length (X1 ) of charge control electrodes (e.g. 503) of an electrode control element (e.g. 500), as later further described in association with at least FIGS. 6A-6B. In one aspect, the length (e.g. D2) of a fluid droplet 129 within the passageway 1 19 also may impact a selection of length (L1 ) of the electrodes 172 on anisotropic conductivity layer 130, with length (D2) of the droplet 129 generally corresponding to a length (X1 ) of the charge control electrodes 503 (FIG. 6A) of an electrode control element 500, in some examples. [0095] With these at least these aspects of example charge-receiving electrodes 172 in mind, the electrodes 172 may be understood as providing a robust manner of ensuring that charges (e.g. 264A) deposited at the anisotropic conductivity layer 130 (at an exterior surface portion 121 of the second plate 120) are effectively and efficiently conveyed through (e.g. via) the conductive paths 134 of the anisotropic conductivity layer 130 to be adjacent to the interior surface 121 of the second plate 120 despite various forms of interference. In some examples, this interference may comprise the presence of debris at the exterior surface portion 122 of the second plate 120, the presence of formation irregularities within the anisotropic conductivity layer 130, the presence of debris on a surface of an external charge applicator 190 (FIG. 1 B) like electrode control element 500 in FIGS. 6A-6B, and/or other types of interference.

[0096] FIGS. 3-14 provide further details regarding the general example arrangement described in association with FIGS. 1A-2B.

[0097] FIG. 3 is a diagram including a side view schematically representing an example device (and/or example method) 200 including an example consumable microfluidic receptacle 202, which includes an anisotropic conductivity layer 130. In some examples, the example consumable microfluidic receptacle 202 may comprise, and/or be employed via, at least some of substantially the same features and attributes as the example consumer microfluidic receptacle 102, as previously described in association with at least FIG. 1 A-2B.

[0098] in some examples, instead of the entire first plate 1 10 being electrically conductive to serve as (or connect to) ground, as further shown in FIG. 3, the first plate 1 10 of the consumable microfluidic receptacle 202 may comprise an electrically conductive layer 1 15, by which the first plate 1 10 may be electrically connected to a ground element 1 13. In some such examples, the electrically conductive layer 1 15 may comprise a material such an indium titanium oxide (ITO) which is transparent and may have a thickness D8 on the order of a few tens of nanometers.

[0099] As further shown in FIG. 3, in some examples, microfluidic receptacle 202 may comprise a first coating 137 on interior surface 1 11 of first plate 1 10 and/or a second coating 136 on interior surface 121 of second plate 120, with such coatings arranged to facilitate electrowetting movement of droplets 129 through a passageway 1 19 defined between the respective plates 110, 120.

[00100] In some examples, at least one of the respective coatings 137,136 may comprise a hydrophobic coating, while in some examples, at least one of the respective coatings 137,136 may comprise a low contact angle hysteresis coating. In some examples, a low contact angle hysteresis coating may correspond to contact angle hysteresis of less than about 30, 29, 28, 27, 26, 25, 24, 23, 22, 21 , or 20 degrees. In some examples, the contact angle hysteresis may comprise less than about 20, 19, 18, 17, 16, or 15 degrees. In some example implementations including coatings 137,136, an oil filler is provided within the passageway 1 19 (e.g. also 319A-319E in FIG. 4), which further enhances the effect of the coatings 137,136. In some examples, the coating 137 and coating 136 may have respective thicknesses of D6, D7 on the order of one micrometer, but in some examples the thicknesses D6, D7 can be less than one micrometer, such as a few tens of nanometers. In some examples, the thicknesses can be greater than one micrometer, such as a few micrometers.

[00101] As further shown in FIG. 3, in some examples the second plate 120 of receptacle 202 may further comprise a dielectric layer 234 interposed between the coating 136 and the anisotropic conductivity layer 130. At least some examples of the dielectric layer 234 are described below in context with, at least, how the dielectric layer 234 may facilitate maintaining a voltage differential across the second plate 120 as part of inducing electrowetting movement of droplet 129. [00102] As further shown in FIG. 3, in some examples the consumable microfluidic receptacle 202 may be used with an external charge applicator (e.g. 190 in FIG. 1 B) embodied as an addressable charge depositing unit 280. The addressable charge depositing unit 280 may be brought into a spaced apart relationship relative to the exterior surface 122 of the second plate 120 of the example arrangement, as represented by the distance D5. In some examples, the distance D5 may comprise about 0.25 millimeters (e.g. 0.23, 0.24, 0.25, 0.26, 0.27) to about 2 millimeters (e.g. 1 .9, 1 .95, 2, 2.05. 2.1 ). In some such examples, the addressable charge depositing unit 280 may be supported by, or within, a frame 233 and the consumable microfluidic receptacle 202 may be releasably supportable by the frame 233 to place the consumable microfluidic receptacle 202 and the addressable charge depositing unit 280 into charging relation to each other. In some examples, the addressable airborne charge depositing unit 280 may sometimes be referred to as a non-contact charge depositing unit, as a noncontact charge head, and the like.

[00103] The addressable charge depositing unit 280 may comprise a wide variety of configurations, depending on the particular type of consumable microfluidic receptacle 202, whether it is stationary or mobile, etc. In some examples, the addressable charge depositing unit 280 may comprise separate charge emitting units for building charges and for neutralizing charges or may comprise charge emitting units which are used for both building charges and for neutralizing charges. In some examples, the addressable charge depositing unit 280 may comprise a two-dimensional array of addressable charge depositing units, such as later described in FIG. 5. In some of these examples, the two- dimensional array may comprise an array of individually controllable electrode nozzles and a corona wire. In some examples, the addressable charge depositing unit 280 may comprise a needle within a cylinder, which under application of appropriate signals, may emit charges.

[00104] As further shown in FIG. 3, upon the consumable microfluidic receptacle 202 and the addressable charge depositing unit 280 being appropriately positioned relative to each other, the addressable charge depositing unit 280 may emit airborne charges 282 toward and onto the exterior surface 122 of the second plate 120, which may then be referred to as deposited charges 264A.

[00105] In some examples the charges 264A are deposited onto a respective one of the electrodes 172 on the exterior surface 146 of the anisotropic conductivity layer 130, which may correspond to a target location T1 to which droplet 129 will be moved via electrowetting.

[00106] As further shown in FIG. 3, in some instances debris 208 may be present on a surface of the electrode 172 on which the charges 264A are deposited and/or a formation irregularity 209 may be present within the anisotropic conductivity layer 130.

[00107] At least with regard to the debris 208, at least some of the emitted airborne charges 282 (from the addressable charge depositing unit 280) will arrive at the electrode 172 as deposited charges 264A. Due to the electrical conductivity of the electrode 172, the electrical effect of those deposited charges 264 will be spread (e.g. current spreading) throughout the entire electrode 172 such as at least in a direction of the plane P2 (e.g. laterally) such that a sufficient amount of the deposited charge 264A becomes transferred to all (or nearly all) of the conductive elements 134 (e.g. conductive paths) which are electrically coupled relative to the electrode 172, including those conductive elements 134 in vertical alignment with the debris 208. In this way, the electrode 172 acts to circumvent the interference or blocking of receipt of charges 282 by debris 208, which might have otherwise prevented charges from being conveyed via the conductive elements 134 in alignment with the debris 208 if the electrode 172 were absent. [00108] Whether or not debris 208 may be present, in some instances a formation irregularity 209 is present within the anisotropic conductivity layer 130, as shown in FIG. 3. The formation irregularity 209 may hamper the ability of the conductive elements 134 (e.g. conductive paths) to convey the deposited charges 264A from the exterior surface 146 to the interior surface 145 of the anisotropic conductivity layer 130. Accordingly, if the example electrodes 172 were not present, deposited charges 264A at exterior surface 146 aligned with the formation irregularity 209 likely would not be conveyed (or conveyed poorly) through the anisotropic conductivity layer 130. However, with the presence of the example electrodes 172 which spread the electrical effect of the deposited charges 264 uniformly throughout the electrode 172 (e.g. current spreading), those same deposited charges 264 (e.g. aligned with the formation irregularity 209) will be conveyed from the exterior surface 146 to the interior surface 145 of the anisotropic conductivity layer 130 via the conductive elements 134 in alignment with a portion of the electrode 172 but which are not affected by the formation irregularity 209.

[00109] In some examples, the deposited charges 264A exhibit a first voltage V1 , which may sometimes be referred to as an applied voltage. Via this arrangement, the addressable charge depositing unit 280 may sometimes be referred to as being in charging relation to consumable microfluidic receptacle 202, and particularly to the second plate 120 and passageway 1 19.

[00110] As shown in FIG. 3, the emitted airborne charges 282 are directed to a target position shown in dashed lines T1 , which is immediately adjacent to the droplet 129. In some such examples, this target position may sometimes be referred to as a virtual electrode, at least to the extent that the dimensions/shape of the area over which the charges are deposited (and the applied voltage resides) may be viewed as being analogous to the dimensions/shape of an electrode pad. In some such examples, the position of the virtual electrode associated with the target position T1 corresponds with the location (and alignment) of electrode 172 of the array 170 at least because the electrode 172 facilitates transfer of the charges 264A in alignment with the target position T 1 .

[00111] As further represented in FIG. 3, the deposited charges 264A at exterior surface 122 of second plate 120 migrate through the conductive elements 134 (e.g. conductive paths) of the anisotropic conductivity layer 130 to an interface 235 between the interior surface 145 of the anisotropic conductivity layer 130 and the dielectric layer 234, as represented by charges 264B. Upon such migration to interface 235, the charges 264B exhibit substantially the same voltage (e.g. V1 ) at the interface 235 as the charges 264A at exterior surface 122 of second plate 120 (and exterior surface 146 of the anisotropic conductivity layer 130).

[00112] With further reference to FIG. 3, with first plate 1 10 being grounded, counter negative charges 266A develop at the first plate 1 10 to cause an electric field (E) between the respective first and second plates 1 10, 120, which creates a pulling force (F) to draw the droplet 129 forward into the target position T1 . In some examples, at least part of this arrangement includes the liquid droplet 129 being conductive (i.e. polar) in at least some examples, such that counter-charges 266B develop within the droplet 129 relative to charges 266A (at first plate 1 10) and counter-charges 264C develop within the droplet 129 relative to charges 264B at interface 235 (between the dielectric layer 234 and the anisotropic conductivity layer 130) within the second plate 120. At least because of the charge differential between the charges 264B and 264C and between the charges 266A and 266B (which corresponds to a voltage differential between V1 and V2), a pulling force is created to pull the droplet 129 from the position (e.g. TO) into the target position T1. Stated differently, the droplet 129 is moved from one virtual electrode to the next/adjacent virtual electrode. Among other aspects, parameters (e.g. dielectric strength, thickness, etc.) associated with the dielectric layer 234 help to maintain the desired charge differential (or voltage differential) which induces the desired droplet movement.

[00113] In some examples, depending on a size, shape, and/or number of electrodes 172, each electrode 172 may be aligned with and correspond to a respective one of the above-mentioned virtual electrodes. However, in some examples of the present disclosure such as, but not limited to, the example arrangement in FIG. 10, such direct correspondence may not be present.

[00114] With further reference to FIG. 3, in some examples the pulling force (F), which causes movement of droplet 129 upon inducing the electric field (E), may comprise electrowetting forces. In some such examples, the electrowetting forces may result from: (1 ) modification of the wetting properties of the interior surface 121 of second plate 120 and/or surface 1 1 1 of plate 1 10 upon application of the electric field (E); (2) counter charges introduced in the droplet 129, which may result from electrical conductivity within the droplet 129 in some examples and/or from induced dielectric polarization within the droplet 129 in some examples; and/or (3) a minimization of the electrical potential energy due to charges in the system including as an example the minimization of the energy due to the counter charges 266A (e.g. negative) and the charges 264A/264B (e.g. positive) in the case of a non-conductive droplet.

[00115] In some examples, the deposited charges 264A at exterior surface portion 122 of second plate 120 may comprise between on the order of tens of volts and on the order of a few hundred volts of charges on the second plate 120. In some examples, the deposited charges 264A may comprise 1000 Volts. In some examples, the deposited charges 264A will dissipate, e.g. discharge upon the addressable charge depositing unit 280 emitting opposite charges (e.g. negative charges). As the droplet 129 moves into the area of the charges (i.e. the target position T1 ), the electric field E drops due to an increased dielectric constant occurring in the effective capacitor which is formed between the respective first and second plates 1 10, 120.

[00116] It will be further understood that charges (e.g. 264A) deposited on the second plate 120 (by the charge depositing unit 280) will be significantly discharged or at least be discharged to a level at which their voltage is significantly lower than the voltage to be applied before the next electrowetting- caused pulling movement of the droplet 129 occurs to the next target position T2. [00117] In some examples, the response time and behavior of the second plate 120 may be related to, and/or expressed in association with, a voltage differential parameter, which may depend, at least in part, on the dielectric properties of the dielectric layer 234, which contribute to the overall dielectric properties of the second plate 120. Various aspects associated with the voltage differential parameter are described further below and throughout various examples of the present disclosure.

[00118] In some examples, the electric properties (e.g. resistivity, etc.) of second plate 120 (which contribute to implementation of the voltage differential are defined, at least in part, by the dedicated dielectric layer 234 of second plate 120. In some examples, the dielectric layer 234 may be an insulating material, comprising a resistivity of at least 10 ¹¹ Ohm-cm, and in some examples, at least 10 ¹³ Ohm-cm.

[00119] In some examples, the dielectric layer 234 may comprise a dielectric strength of at least 50 V/micrometers (e.g. 49.5, 49.6, 49.7, 49.8, 49.9,

50.1 . 50.2, 50.3, 50.4, 50.5), while in some examples, the dielectric layer 234 may comprise at least 100 V/micrometers (e.g. 99.5, 99.6, 99.7, 99.8, 99.9, 100.1 ,

100.2, 100.3, 100.4, 100.5). In some examples, the dielectric layer 234 may comprise at least about 200 V/micrometers (e.g. 199.5, 199.6, 199.7, 199.8, 199.9, 200.1 , 200.2, 200.3, 200.4, 200.5). In some examples, the dielectric layer 234 may comprise at least about 300 V/micrometers (e.g. 299.5, 299.6, 299.7, 299.8, 299.9, 300.1 , 300.2, 300.3, 300.4, 300.5).

[00120] In some examples, second plate 120 (including the dedicated dielectric layer 234) may implement the above-mentioned voltage differential parameter, which corresponds to the extent to which a voltage differential across at least the dielectric layer 234 of second plate 120 is substantially preserved (i.e. maintained with a significant magnitude) during a predetermined, dropletmovement time period. In some such examples, this voltage differential parameter may sometimes also be expressed as substantially preventing a decay of the voltage differential across the second plate 120 (including the dielectric layer 234).

[00121] In considering the behavior of a voltage differential across at least the dielectric layer 234 of second plate 120, it will be understood that in at least some examples the droplet is generally electrically conductive and therefore droplet 129 generally sits at a voltage close to ground. In some such examples, in this context the droplet 129 may be considered to be conductive, having a resistivity less than 10 ⁷ ohm-cm. Given this general conductivity of the droplet 129, it will be further understood that the above-described, the applied voltage differential occurs entirely (or substantially entirely) across material within the second plate 120 which exhibits dielectric properties, such as the dielectric layer 234.

[00122] Moreover, as noted elsewhere among the various examples, of the present disclosure, materials of the dielectric layer 234 may exhibit compatibility with hydrophobic layer 236, as further described later.

[00123] In some examples, the dielectric layer 234 may comprise a dielectric material having a thickness of at least about 10 micrometers (e.g. 9.7, 9.8, 9.9, 10.1 , 10.2, 10.3). In some examples, the dielectric layer 234 may comprise a dielectric material having a thickness of at least about 20 micrometers (e.g. 19.7, 19.8, 19.9, 20.1 , 20.2, 20.3). In some examples, the dielectric layer 234 may comprise a dielectric material having a thickness of at least about 50 micrometers (e.g. 49.7, 49.8, 49.9, 50.1 , 50.2, 50.3).

[00124] In some such examples, the dielectric material comprise a combination (e.g. hybrid) of organic material and inorganic materials, which may comprise coatings provided in liquid form and cured via many possible routes. In some such examples, the dielectric material of layer 234 may comprise monomers/prepolymers that contain inorganic silicon-oxygen groups as well as reactive organic functional groups.

[00125] In at least some example implementations of such materials, the dielectric layer 134 may comprise a thickness of at least on the order of hundreds of nanometers to about 20 micrometers. In some examples, the thickness may depend on the dielectric strength, dielectric properties, voltage used, and/or coating or deposition techniques. In some examples, a pre-made film like a polyimide film may be formed using lamination or other adhesion techniques.

[00126] In at least some of the foregoing example combination of organic and inorganic materials to form a dielectric layer, solvent(s) may be used to enable the liquid coating process, for viscosity adjustment, etc. [00127] In some examples, the dielectric layer 234 may comprise other materials different from the above-described combination of inorganic material and inorganic materials. In some such examples, a dielectric layer 234 comprising these other materials may comprise a thickness of at least about 10 micrometers (e.g. 9.7, 9.8, 9.9, 10.1 , 10.2, 10.3). In some examples, these other materials may comprise a polyimide material, which may comprise a polyimide material such as a Kapton® material obtainable from DuPont de Nemours, Inc. In some examples, the other materials (from which dielectric layer 234 may be formed) may comprise a polyetherimide (PEI) material.

[00128] In some examples, the other materials (from which dielectric layer 234 may be formed) may comprise films in a fluoropolymer class of materials, and may comprise a perfluoroalkoxy alkane (PFA) material, an ethylene tetrafluorotethylene (ETFE) material, a polychlorotrifluoroethylene (PCTFE) material, or a fluorinated ethylene propylene (FEP) material. In some examples, these films may comprise a dielectric strength of at least 50 V/micrometers and are intrinsically compatible with many fluorinated-based hydrophobic coatings.

[00129] In some examples, these films can be adhered to the substrate in a variety of methods. First, the film may be commercially available with an adhesive backing, with typical adhesives being in the silicone or acrylic family. Second, a curable adhesive may be applied between the substrate and the film. The adhesive can be cured by either a hardener (two-pack epoxy or two-pack silicone system for example) or by a UV source as for a UV-curable adhesive. For all the cases above, one surface of the dielectric film may be surface treated by a variety of methods (e.g. corona, oxygen plasma, and UV ozone) to enhance adhesion.

[00130] In one example implementation of the above-described arrangement, the dielectric layer 234 may comprise a combined film and adhesive structure having a thickness of about 25 micrometers. For instance, the dielectric layer 234 may comprise a polyimide material in form of a tape, such as a Kapton® tape, including a silicone adhesive. One such example may comprise a film/adhesive combination available from Caplinq of Ottawa, Ontario, Canada. The polyimide film may comprise a thickness of about 12.5 micrometers. Meanwhile, the silicone adhesive portion may comprise a thickness of about 12.5 micrometers and is suitable for laminating via pressure to a substrate (e.g. a PCB, other). In some examples, with a thickness of 12.5 micrometers, the dielectric strength of the polyimide film comprises about 300 V/mi orometers.

[00131] During the charging of the ion head and deposit of charges 264A at exterior surface 122 of the second plate 120, the ground current is close to zero (e.g. at droplet 129) because the relatively high dielectric strength (and thickness) of the dielectric layer 234 substantially eliminates or prevents migration of charges through to ground. In some examples, shortly (e.g. 2 seconds) after charging of the exterior surface 122 of second plate 120 ends, a magnitude of the second voltage V2 (e.g. - 700 Volts) adjacent the interior surface 121 of the second plate 120 (such as within a portion of droplet 129) is substantially the same as a magnitude of the first voltage V1 (e.g. about 700 Volts) at the exterior surface 122 of the second plate 120, which also appears at the interface 235 (between the substrate 132 and the dielectric layer 234). In this arrangement, the voltage differential between the interface 235 and a portion of the droplet 129 (adjacent the interior surface 121 of the second plate 120) easily meets the voltage differential preservation parameter of V2=0.5 x V1 because the V2 of 700 significantly exceeds 350, which is 0.5 x 700 (V1 ).

[00132] In a related aspect, the second voltage V2 remains substantially stable at least during the droplet-movement time period. In some examples, a velocity of droplet movement may comprise between about 1 mm/second and 30 mm/second. Accordingly, in some examples which an electrode has a length (e.g. D2 in FIG. 1 A, 3) of about 3 millimeters, one example droplet-movement time period may comprise between about 0.1 and about 3 seconds. In one example, the time period may comprise about 2 seconds.

[00133] As previously noted, in some examples, the voltage differential parameter may be expressed as a voltage differential preservation parameter to the extent that a voltage differential across at least the dielectric layer is substantially preserved over a predetermined period of time during which the droplet is to move from a first position to a second position. This time period may sometimes be referred to as a droplet-movement time period or dropletmovement actuation time period. In some examples, the voltage differential parameter may be expressed as a voltage differential decay parameter to the extent that decay of a voltage differential across the second plate is substantially prevented over a predetermined period of time, such as the droplet-movement time period (or actuation time period).

[00134] In some examples, the voltage differential parameter may be expressed as a charge retention parameter to the extent that charges at an interface of the dielectric layer and the substrate of the second plate are substantially retained over the predetermined period of time during which the droplet is to move from a first position to a second position. Via this arrangement, a charge differential or voltage differential is retained between the charges at the interface (i.e. the interface of the dielectric layer and the substrate of the second plate) and a portion of the droplet (adjacent an interior surface of the second plate) at least during the droplet-movement time period.

[00135] With this in mind, in some examples the voltage differential engine 1240 may control or manage a voltage differential according to parameters regarding a material type, a thickness, a dielectric strength, an applied voltage (e.g. V1 at 122, V1 at 135), and a time period. In some examples, parameters regarding the material type, thickness, and dielectric strength may be implemented with regard to solely the dielectric layer (e.g. 234) while in some examples, these parameters may be implemented with regard to the second plate (e.g. 120, etc.) as a whole including the dielectric layer 234. In some examples, the parameters regarding the material type, thickness, and dielectric strength may be implemented with regard to both the dielectric layer (e.g. 234) and the hydrophobic layer 236. In some examples, parameters regarding voltage and a time period may depend on the other parameters, desired performance, type of microfluidic operations, or other factors. In some examples, the voltage parameter also may include control or specification of voltages such as internal voltages (e.g. V3) of a charge depositing unit, control voltages (VC) of the charge depositing unit (which are used to set the applied voltage V1 , etc.

[00136] With further reference to FIG. 3 and the deposited charges 264B at interface 235 in some examples, the addressable charge depositing unit 280 also may be used to neutralize charges at interface 235 (or also on exterior surface 122 of) second plate 120, such as after a desired droplet movement has occurred. In particular, in some arrangements, the addressable charge depositing unit 240 may be used to neutralize residual charges so as to prepare the microfluidic receptacle (e.g. portion of a microfluidic device) to receive a deposit of fresh charges (e.g. 264A) in preparation of causing further electrowetting movement of the droplet 129 to a next target position (e.g. T2).

[00137] It will be understood that in some examples, the addressable charge depositing unit 280 may be mobile and the microfluidic receptacle 102 may be stationary while performing microfluidic operations, while in some examples, the addressable charge depositing unit 280 may be stationary and the microfluidic receptacle 202 is moved relative to the addressable charge depositing unit 280 during microfluidic operations. In some examples, the frame 233 (FIG. 3) may including portions, mechanisms, etc. which may facilitate relative movement between the consumable microfluidic receptacle 102 and the charge depositing unit 280.

[00138] In some examples, both of the addressable charge depositing unit 280 and the microfluidic receptacle 202 are stationary during microfluidic operations, with the addressable charge depositing unit 280 being arranged in a two-dimensional array to deposit charges in any desired target area of the microfluidic receptacle in order to perform a particular microfluidic operation or sequence of microfluidic operations. At least some example implementations of such a two-dimensional array may comprise at least some of the substantially the same features and attributes as described in association with at least FIG. 5.

[00139] In some examples, such microfluidic operations to be performed via the consumable microfluidic receptacle 102 and an addressable charge depositing unit (e.g. 280 in FIG. 1 A) may be implemented in association with a control portion, such as but not limited to control portion 1300 in FIG. 13B and/or in association with a fluid operations engine 1200 in FIG. 13A.

[00140] In some examples, as shown in FIG. 3, each target position (e.g. T1 ,T2, etc.) may comprise a length (D2) which may comprise a length expected to be approximately the same size (e.g. length D2) as the droplet 129 to be moved. In view of the example volumes of droplets noted above, the length (D2) of each target position (e.g. T1 , T2, etc.) may comprise between about 50 micrometers to about 5 millimeters, and may comprise a width similar to its length in some examples. In some examples, the target position also may sometimes be referred to as a droplet position. As also previously noted, each of the respective droplet position also may sometimes be referred to as corresponding to the position, size, and/or shape of the above-described virtual electrodes of the second plate 120, which in some examples may correspond to a position, size and/or shape of the charge-receiving electrodes 172 formed on the anisotropic conductivity layer 130.

[00141] In some examples, the length (D2) of the droplet in passageway 1 19 may sometimes be referred as a length scale of the droplet (or target position of a droplet). In sharp contrast to some other devices which utilize an array of control electrodes and which involve spacing between adjacent control electrodes because of manufacturing limitations, in at least some examples of the present disclosure, the target positions (e.g. T1 , T2) may be immediately adjacent each other with virtually no spacing therebetween. Accordingly, at least some examples of the present disclosure do not face at least some of the challenges in moving droplets that may otherwise be posed by a distance between adjacent electrodes in such devices employing active control electrodes.

[00142] In some examples, the example arrangements of the present disclosure to cause electrowetting movement of droplets stand in sharp contrast to some microfluidic devices which rely on dielectrophoresis to produce movement of particles. At least some such dielectrophoretic devices comprise a distance between control electrodes (of a printed circuit board which form one of the microfluidic plates) which is substantially greater (e.g. 10 times, 100 times, etc. ) than a length scale (e.g. size) of a particle within a liquid to be moved. For instance, the distance between control electrodes (in some dielectrophoretic devices) may be on the order of hundreds (i.e. 100’s) of micrometers, whereas the length scale of such particles may comprise on the order of hundreds (i.e. 100’s) nanometers. In some such devices, the distance between electrodes in a dielectrophoretic device may sometimes be referred to as a length scale of such electrodes or as a length scale of the gradient (i.e. gradient length scale). [00143] For comparison purposes to some dielectrophoretic devices, a droplet of liquid to be moved via electrowetting forces in at least some examples of the present disclosure may comprise a thickness between a first plate 1 10 and second plate 120 of about 200 micrometers, and a length (or width) extending across a target position (e.g. T1 , T2) (i.e. droplet position) of about 2 millimeters, in some examples. In sharp contrast, dielectrophoresis may cause movement of a particle within a mass of fluid, where such particle may be about 100 nanometers diameter (or length, width, or the like) and many particles may reside within a droplet of liquid. However, the dielectrophoretic device does not generally cause movement of an entire fluid mass.

[00144] FIG. 4 is a diagram including top plan view schematically representing an example microfluidic device 300. In some examples, the microfluidic device 300 comprises at least some of substantially the same features and attributes as the consumable microfluidic receptacle 102, 202 in FIGS. 1 A-3 and 5-14. In particular, in some examples, the microfluidic receptacle 102 in FIG. 1 A (and related examples in FIGS. 2B-14) may comprise at least a portion of the example microfluidic device 300.

[00145] As shown in FIG. 4, the microfluidic device 300 comprises a frame 305 within which is formed an array 315 of interconnected passageways 319A, 319B, 319C, 319D, 319E, with each respective passageway being defined by a series of target positions 317. In some examples, the respective passageways 319A-319E are defined between a first plate (like first plate 1 10 in at least FIGS. 1 A, 3, 6B) and a second plate (like second plate 120 at least in FIGS. 1 A, 3, 6B), with each target position 317 corresponding to a target position (e.g. T1 or T2 in FIGS. 3, 6B) at which a droplet 129 (FIGS. 1 A, 3, 6B) may be positioned. In some examples, each target position 317 may comprise a length of about 500 to about 1500 micrometers while in some examples the length may be about 750 to about 1250 micrometers. In some examples, the length may be about 1000 micrometers. Meanwhile, in some examples, each target position 317 may have a width commensurate with the length, such as the above-noted examples.

[00146] As previously noted in association with FIGS. 1 A, 3, 6B, the respective target positions 317 and the passageways 319A-319E do not include active control electrodes (and related circuitry) for moving droplets 129. Rather, droplets 129 are moved through the various passageways 319A, 319B, 319B, 319D, 319E via electrowetting forces caused by directing charges from the external charge applicator 190 (FIG. 1 B), which may comprise the addressable charge depositing unit 280 (FIG. 3) or the electrode control element 500 (FIG. 6), in some examples. Accordingly, via the use of such an externally-applied charges to induce an electric field as described in FIG. 3, the droplet(s) 129 move through the passageways via electrowetting forces without any active control electrodes (and related circuitry) lining the paths defined by the various passageways 319A- 319E. In some examples, the electrode control element 500may sometimes be referred to as a releasable contact, electrode control element.

[00147] As further shown in FIG. 4, at least some of the respective target positions 317, such as at positions 321 A, 321 B, 323A, and/or 323B may comprise an inlet portion which can receive a droplet 129 to begin entry into the passageways 319A-319E to be subject to microfluidic operations such as moving, merging, splitting, etc. In some examples, some of the example positions 321 A, 321 B, 323A, 323B may comprise an outlet portion, from which fluid may be retrieved after certain microfluidic operations.

[00148] It will be understood that in some examples, the consumable microfluidic device 300 may comprises features and attributes, in addition to those described in association with FIGS. 1 -3 and/or 5-14. For example, in some instances, prior to receiving droplets 129, the microfluidic device 300 may comprise at least one fluid reservoir R at which various fluids (e.g. reagents, binders, etc.) may be stored and which may be released into at least one of the passageways 319A-319E. In some examples, release of such reagents or other materials may be caused by the same externally-caused electrowetting forces as previously described to cause movement of droplet 129. Moreover, in some examples, at least some of the passageways 319A-319E may form or define a lateral assay flow device in which some reagents, etc. may already be present at various target positions 317 within a particular passageway (e.g. 319A-319E) such that upon movement of various droplets 129 relative to such target positions 317 may result in desired reactions to effect a lateral flow assay. However, in some examples, the microfluidic device 300 does not store any liquids on board, and any liquids on which microfluidic operations are to be performed are added, such as in the example inlet locations 321 A, 321 B, 323A, 323B, as previously described.

[00149] Via the externally-caused electrowetting movement of the respective droplets within the passageways 319A-319E, various microfluidic operations of moving, merging, splitting may be performed within microfluidic device 300 to cause desired reactions, etc. With this in mind, in some examples a portion of the consumable microfluidic device 300 may comprise at least one sensor (represented by indicator S in FIG. 4) to facilitate tracking the status and/or position of droplets within a microfluidic device, as well as for determining a chemical or biochemical result ensuing from the various microfluidic operations, such as merging, splitting, etc. In some such examples, such sensors may be incorporated into the first plate 1 10 (FIG. 1 A) so as to not interfere with the deposit of charges, migration of charges, neutralization of charges, etc. occurring at or through the second plate 120 (FIG. 1A). In some examples the sensor(s) may include external sensors, like optical sensors. In some such examples, such external sensors may be used to sense attributes of a fluid retrieved from an above-described outlet portion.

[00150] In some examples, such microfluidic operations to be performed via the microfluidic device 300 and an external charge applicator (190 in FIG. 1 B, 280 in FIG. 3, 500 in FIG. 6B) may be implemented in association with a control portion, such as but not limited to control portion 1300 in FIG. 13B and/or in association with a fluid operations engine 1200 in FIG. 13A.

[00151] FIG. 5 is a diagram including a side view schematically representing an example two-dimensional addressable charge depositing unit 415 in charging relation to a second plate 420 of a consumable microfluidic receptacle (e.g. 102, 202 in FIGS. 1 A, 3). In some examples, the addressable charge depositing unit 415 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable charge depositing unit 280 in FIG. 3. Meanwhile, the second plate 420 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the consumable microfluidic receptacle 102, 202 described in association with at least FIGS. 1 A-4 and 6A-14. [00152] As shown in FIG. 5, addressable charge depositing unit 415 comprises a two dimensional array 441 of addressable charge depositing elements as represented by the arrows 442. The array 441 comprises a size and a shape to cause electrowetting movement of droplets 129 to any one target position (e.g. 317 in FIG. 4) of a corresponding array 418 of target droplet positions (e.g. 317 in FIG. 4) of the consumable microfluidic receptacle 102, 202 FIGS. 1 A, 3). In some examples, each addressable charge depositing element 442 may correspond to an addressable charge depositing unit 280 in FIG. 3, which may be operated to generate airborne charges (of a desired first polarity or opposite second polarity) in order to deposit and build charges on an exterior surface 422 of second plate 420 (of a consumable microfluidic receptacle) to cause a desired direction of movement of a droplet along a passageway (e.g. 319A-319E in FIG. 4) within the consumable microfluidic receptacle. In some such examples, any one of the addressable charge depositing elements 442 also may be operated in a charge neutralizing mode, to emit single polarity charges (e.g. negative), or to emit charges of both a first and second polarity (e.g. negative, positive) via an AC signal.

[00153] Via the two-dimensional arrangement shown in FIG. 5, both the second plate 420 of the microfluidic device and the addressable charge depositing unit 415 remain stationary while the array 441 of addressable charge depositing elements 442 may be selectively operated (e.g. individually controllable) to control electrowetting movement for any or all of the target positions (e.g. 317 in FIG. 4) of the second plate 420 of the consumable microfluidic receptacle (e.g. 102, 202 in FIGS. 1 A, 3).

[00154] FIG. 6A is a diagram including a side view schematically representing an example electrode control element 500. In some examples, the electrode control element 500 comprises one example implementation of the external charge applicator 190 (FIG. 1 B) such that the electrode control element 500 may be used instead of the addressable charge depositing unit 280 (FIG. 3) to apply charges to cause electrowetting droplet movement in the manner described in FIG. 3. [00155] With this in mind, as shown in FIG. 6A, electrode control element 500 comprises a base 505 which may comprise an insulative material which houses circuitry (and/or conductive elements connectable to circuitry) for controlling generation and application of charges (e.g. 264A in FIG. 3) via each of the addressable electrodes 503. In some examples, the electrode control element 500 may be implemented in the form of a circuitry substrate, which may comprise a printed circuit board (PCB) or thin film transistor (TFT) structure.

[00156] In some examples, microfluidic operations to be performed via the consumable microfluidic receptacle (e.g. 102, 202) and the addressable electrode control element 500 of FIGS. 6A-6B may be implemented in association with a control portion, such as but not limited to control portion 1300 in FIG. 13B and/or in association with a fluid operations engine 1200 in FIG. 13A. Such operations may also comprise control of the later-described relative movement and/or other later-described operational aspects associated with the receptacle 102, 202 and/or electrode control element 500.

[00157] In some examples, as shown in FIG. 6A, each electrode 503 of electrode control element 500 may comprise a length (X1 ) expected to be approximately the same size as the droplet 129 to be moved, as shown in FIG. 6B. In view of the example volumes of droplets noted above, the length (X1 ) of each electrode 503 may comprise between about 50 micrometers to about 5 millimeters, and may comprise a width similar to its length in some examples. In some examples, the length (X1 ) may comprise between about 100 micrometers and 3 millimeters, while in some examples, the length (X1 ) may comprise about 2 millimeters. In some examples, the length (X1 ) of each electrode 503 may be commensurate with the length (D2 in FIG. 3, 6B) of a droplet or target position (e.g. T1 , T2) of a droplet 129 within the consumable microfluidic receptacle 102, 202 (FIGS. 1 A, 3). [00158] As previously mentioned, in some examples, the length (D2) of the droplet in passageway 1 19 (e.g. FIG. 1 A, 3A, 6A-6B) may sometimes be referred as a length scale of the droplet, or a length of a target position of a droplet. Meanwhile, the distance (X2) between adjacent electrodes 503 as shown in FIG. 6A may sometimes be referred to as the length scale of the electrodes 503. In some examples, the length scale (X2) between electrodes 503 may comprise about 50 to about 100 micrometers and also may sometimes be referred to as spacing between electrodes 503. In some examples, this spacing may comprise about 75 micrometers.

[00159] As shown in FIG. 6B, in some examples the addressable electrode control element 500 may be brought into releasable contact against the exterior surface 122 of the second plate 120 of an example consumable microfluidic receptacle 102. In some such examples, the addressable electrode control element 500 may be supported by or within a frame 233 and the consumable microfluidic receptacle 102 may be releasably supportable by the frame to place the consumable microfluidic receptacle 102 and the addressable electrode contact element 500 into releasable contact and charging relation to each other. As shown in FIG. 6B, this arrangement places the electrodes 503 of the electrode control element 500 into direct contact against the electrodes 172 on the anisotropic conductivity layer 300 of the second plate 120. In some examples, the electrodes 172 at exterior surface 122 of second plate 300, and a first surface 501 (e.g. top surface) of the control element 500 are each planarized to facilitate establishing robust mechanical and electrical connectivity when brought and maintained in releasable contact together.

[00160] For illustrative simplicity, FIG. 6B depicts the microfluidic receptacle 102 without the dielectric layer 234 and hydrophobic layer 236 previously shown for microfluidic receptacle 202 in FIG. 3, and without the detailed illustration of counter-charges, voltages V1 , V2 and related concepts. However, it will be understood that the microfluidic receptacle 102 in FIG. 6B comprises at least some of substantially the same features and attributes as the microfluidic receptacle 202 in FIG. 3 regarding the migration of charges, operation of countercharges, voltages V1 , V2 as consumable microfluidic receptacle 202 in FIG. 3, except with the deposited charges 264A originating from electrode control element 500 (FIG. 6B) instead emanating from of the addressable charge depositing unit 280 in FIG. 3.

[00161] As further shown in FIG. 6B, upon the addressable electrode control element 500 being brought into releasable contact against the consumable microfluidic receptacle 102, a selected electrode(s) 503 of the addressable electrode control element 500 may apply charges 264A directly onto the chargereceiving electrodes 172 onto the exterior surface 122 of the anisotropic conductivity layer 130 of the second plate 320, with these charges being sometimes referred to as deposited charges 264A.

[00162] In some examples, the electrodes 172 on exterior surface portion 146 of anisotropic conductivity layer 130 act in a manner comprising at least some of substantially the same features and attributes as described in association with at least FIG. 3 in order to facilitate conveyance of deposited charges 264A from the exterior surface portion 146 to the interior surface portion of the anisotropic conductivity layer 130 despite the presence of dirt and/or formation irregularities on or within the anisotropic conductivity layer 130.

[00163] Moreover, further example implementations of the example electrodes 172 and related variations of the anisotropic conductivity layer 130 are described below in association with at least FIGS. 9-12.

[00164] After the charges 264A are deposited on electrodes 172 at surface 122 of second plate 120 of receptacle 102, the charges 264A behave in a manner substantially similar to that described in association with at least FIG. 3 to cause electrowetting movement of droplet 129 within and through passageway 1 19 of receptacle 102.

[00165] With further reference to FIG. 6B, via the formed electrodes 172 on anisotropic conductivity layer 130, each electrode 503 selected from array 502 (of electrodes 503) is aligned with a target position T 1 (represented via dashed lines), which is immediately adjacent to the droplet 129 and to which the droplet 129 is to be moved.

[00166] In some examples, the addressable electrode control element 500 also may be used to neutralize charges on second plate 120 so as to prepare the microfluidic receptacle 102 (e.g. 202 in FIG. 3) to receive an application of fresh charges from electrode control element in preparation of causing further controlled pulling movement of the droplet 129 to a next target position (e.g. T2). [00167] It will be further understood that charges (e.g. 264A) applied on electrode 172 of the second plate 120 (by the electrode control element 500) will be significantly discharged or at least be discharged to a level at which their voltage is significantly lower than the voltage to be applied before the next electrowetting- caused pulling movement of the droplet 129 occurs to the next target position T2. [00168] In some examples, both of the addressable electrode control element 500 and the consumable microfluidic receptacle 102 (e.g. 202 in FIG. 3) are stationary during microfluidic operations, with the addressable electrode control element 500 being arranged in a two-dimensional array to apply charges in any desired target location (e.g. 317 in FIG. 4) of the microfluidic receptacle in order to perform a particular microfluidic operation or sequence of microfluidic operations. One example implementation of a two-dimensional array of such electrodes is described later in association with at least FIG. 8.

[00169] However, it will be understood that in some examples, the electrode control element 500 may be mobile and the consumable microfluidic receptacle 102 may be stationary while performing microfluidic operations, while in some examples, the addressable electrode control element 500 may be stationary and the consumable microfluidic receptacle 102 is moved relative to the addressable electrode control element 500 during microfluidic operations. In some examples, frame 233 may include portions, mechanisms, etc. which may facilitate relative movement between the consumable microfluidic receptacle 102 and the electrode control element 500.

[00170] FIGS. 7A-7B are each a diagram including a side view schematically representing example alignments between charge control electrodes 503 of an electrode control element 500 (FIGS. 6A-6B) relative to charge-receiving electrodes 172 formed on anisotropic conductivity layer 130 of a consumable microfluidic receptacle 102, 202. In some examples, the control electrodes 503 in FIG. 7A, 7B may comprise at least some of substantially the same features and attributes as the electrodes 503 previously described in association with at least FIGS. 6A-6B. In some examples, the electrodes 172 in FIG. 7A, 7B may comprise at least some of substantially the same features and attributes as the electrodes 172 of anisotropic conductivity layer 130 described in association with at least FIGS. 1 -6B and/or analogous electrodes in FIGS. 9-12. [00171] As shown in FIG. 7A, when electrode control element 500 is in releasable contact with the electrodes 172 (of anisotropic conductivity layer 130), in some examples the charge control electrodes 503 may be completely aligned with (e.g. in proper registration with) the charge-receiving electrodes 172 of the anisotropic conductivity layer 130. In such examples, outer edges 515 of the control electrodes 503 (of electrode control element 500) are located between (e.g. within) the outer edges 175 of the charge-receiving electrodes 172 (on anisotropic conductivity layer 130).

[00172] As further shown in FIG. 7A, in some examples a spacing 01 between an outer edge 515 of a control electrode 503 and an outer edge 715 of a charge-receiving electrode 172 may provide one measure of a degree of complete overlap between the respective electrodes 503, 172. In one aspect, the charge control electrodes 503 may sometimes be referred to as being coextensive with charge-receiving electrodes 172. In some examples, a target value of spacing 01 between the respective outer edges 515, 172 may be selected when forming the charge-receiving electrodes 172 assuming knowledge of the length (X1 ) of the charge control electrodes 503 of the electrode control element 500.

[00173] As further shown in FIG. 7A, in some examples of complete overlap, a gap G1 between adjacent charge-receiving electrodes 172 (on the anisotropic conductivity layer 130) may be less than a gap X2 between adjacent control electrodes 503 of the electrode control element 500.

[00174] In contrast to the complete alignment depicted in FIG. 7A, FIG. 7B illustrates electrodes 503 of electrode control element 500 being partially offset relative to the charge-receiving electrodes 172 (of anisotropic conductivity layer 130), as represented by the distance R1 between the outer edge 715 of electrode 172 and the outer edge 515 of electrode 503 of electrode control element 500. Despite this offset, the significant degree of overlap between the control electrodes 503 and the charge-receiving electrodes 172 may still result in a sufficient transfer of charges from control electrodes 503 to electrodes 172 (on anisotropic conductivity layer 130). In one aspect, the presence of, and the position of, the charge-receiving electrodes 172 may ensure that the charges from the misaligned electrodes 503 become conveyed at the proper target location (e.g. T 1 , T2) in passageway 1 19. [00175] FIG. 8 is a diagram including a side view schematically representing an example arrangement 651 comprising a two-dimensional addressable electrode control element 650 in charging relation to a second plate 660 of a consumable microfluidic receptacle 658. In some examples, the addressable electrode control element 650 may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the addressable electrode control element 500 described in association with at least FIGS. 6A-7B. Meanwhile, the second plate 660 (and associated consumable microfluidic receptacle 658) may comprise one example implementation of, and/or may comprise at least some of substantially the same features and attributes as, the second plate 120 and consumable microfluidic receptacle 102, 202 as described in association with at least FIGS. 1 A-7B.

[00176] As shown in FIG. 8, the example addressable electrode control element 650 comprises a two dimensional array 681 of individually controllable (e.g. addressable) electrodes 683. The array 681 comprises a size and a shape to cause controlled movement of droplets 129 to any one target position (e.g. 317 in FIG. 4) of a corresponding array of target droplet positions (e.g. 317 in FIG. 4) implemented via the second plate 660 of the consumable microfluidic receptacle 658. In some examples, at least some of the respective example addressable electrodes 683 of control element 650 may correspond to the example electrodes 503 shown in FIGS. 6A-6B, which may be operated to apply charges (of a desired first polarity or opposite second polarity) in order to deposit charges on the electrodes 172 of the exterior surface 122 of anisotropic layer 130 of second plate 660 (of the consumable microfluidic receptacle 658) to ultimately cause a desired direction of movement of a droplet along a passageway (e.g. 319A-319E in FIG. 4) within the consumable microfluidic receptacle 658. In some such examples, any one of the addressable electrodes 683 also may be operated in a charge neutralizing mode in which charges are emitted having a polarity (e.g. negative) opposite the polarity of the charges (e.g. positive) used to initiate an electrowetting movement of the liquid droplet 129.

[00177] Via the two-dimensional arrangement 651 shown in FIG. 8, both the second plate 660 of the consumable microfluidic receptacle 658 and the addressable electrode control element 650 remain stationary while the various respective addressable electrodes 683 (of array 681 ) may be selectively operated (e.g. individually controlled) to control droplet movement for any or all of the target positions (e.g. 317 in FIG. 4) of the second plate 660 of the consumable microfluidic receptacle 658.

[00178] FIG. 9 is a diagram including a side view schematically representing at least a portion of an example consumable microfluidic receptacle 700 and an electrode control element 500 prior to releasable contact with the receptacle 700. As shown in FIG. 9, in some examples the receptacle 700 comprises at least some of substantially the same features and attributes as the consumable receptacles 102, 202 of FIGS. 1 A-8, except with an anisotropic conductivity portion 730 separated into two different layers 728A, 728B with a layer of an array 170 of charge-receiving electrodes 172 formed (and sandwiched between) the two respective anisotropic conductivity layers 728A, 728B. The array 170 (e.g. layer) of spaced apart electrodes 172 may sometimes be referred to as being interposed between the first and second anisotropic conductivity layers 728A, 728B.

[00179] For illustrative simplicity, the first plate 110 (FIG. 1 A, 3, 6B) is not shown in the schematic representation of FIG. 9, but the first plate 1 10 would be understood as still forming part of the consumable microfluidic receptacle 700.

[00180] As further shown in FIG. 9, the consumable microfluidic receptacle 700 comprises a second plate 720 like second plate 120 in FIGS. 1 A, 3, and 6B, with second plate 720 including a dielectric layer 234 and a hydrophobic layer 236, like similar layers in FIG. 3.

[00181] As shown in FIG. 9, in some examples, the second plate 720 also comprises an anisotropic conductivity portion 730, which includes a first anisotropic conductivity layer 728A, a second anisotropic conductivity layer 728B, and a layer 170 of charge-receiving electrodes 172 interposed between the layers 728A, 728B. In a manner substantially similar to that described in association with at least FIGS. 1 A, 3, and 6B, the presence of electrodes 172 in anisotropic conductivity portion 730 may overcome deleterious effects which might otherwise ensue from the presence of debris 208 and/or formation irregularities 209 within one or both of the anisotropic conductivity layers 728A, 728B.

[00182] In some such examples, the first anisotropic conductivity layer 728A may comprise a rigid structure, which the second anisotropic conductivity layer 728B may comprise a compliant structure to facilitate releasable engagement relative to the electrode control element 500 in order increase a degree of contact between the electrodes 503 and the exterior surface portion 722 of the second plate 720.

[00183] In some examples, the first anisotropic conductivity layer 728A may comprise an interior surface 745 connected to dielectric layer 234 and an opposite exterior surface portion 746 on which the electrodes 172 are formed. The second anisotropic conductivity layer 728B may comprise an interior surface 747 formed on or at the electrodes 172 and an exterior surface portion 748 acting as the exterior surface portion 722 of the second plate 720.

[00184] As further shown in FIG. 9, the first and second anisotropic conductivity layers 728A, 728B extend in planes P1 , P3 which are generally parallel to each other, and generally parallel to a plane P2 through which the layer of electrodes 172 extends.

[00185] FIG. 10 is a diagram including a side view schematically representing an example consumable microfluidic receptacle 750 and an electrode control element 500 prior to releasable contact with the receptacle 750. As shown in FIG. 10, in some examples the receptacle 750 comprises at least some of substantially the same features and attributes as the consumable receptacles 102, 202 of FIGS. 1 A-8, except with the layer 780 of charge-receiving electrodes 782 formed on the exterior surface 746 of anisotropic conductivity layer 728A having varying sizes and/or shapes. In some examples, the sizes and/or shapes of the electrodes 782 may vary on a pseudo-random basis. As shown in FIG. 10, in some examples a size and/or shape of the electrodes 782 may be significantly less than a size and/or shape of a respective one of the single electrodes 503 of the electrode control element 500 which applies charges to the electrodes 782 (i.e. the current spreading electrodes 782). [00186] As shown in FIG. 19, in some examples, each charge-receiving electrode 782 may have a length Y1 , which varies from among the various electrodes 782. Similarly, the gap G2 between adjacent pairs of electrodes 782 also may vary in some examples, or the gap G2 may be the same between adjacent pairs of electrodes 782, in some examples.

[00187] As previously mentioned, the pseudo-random pattern of electrodes 782 may be formed via a vapor deposition process, which may comprise sputtering or splattering.

[00188] In some examples, the pseudo-random pattern of electrodes 782 may provide for a more overall robust arrangement to facilitate conveyance of deposited charges (e.g. 264A in FIGS. 1 A, 3, 6B) because a location of formation irregularities 209 may not be known or knowable and/or a location of debris 208 will nearly always be variable.

[00189] FIG. 1 1 is a diagram including a side view schematically representing an example consumable microfluidic receptacle 800 and an electrode control element 500 prior to releasable contact with the receptacle 800. As shown in FIG. 1 1 , in some examples the receptacle 800 comprises at least some of substantially the same features and attributes as the consumable receptacles 102, 202 of FIGS. 1A-8, except with a layer 870 (e.g. array) of electrodes 872 sandwiched between the anisotropic conductivity layer 728A and the dielectric layer 234 of second plate 820. The electrodes 872 may sometimes be referred to as being interposed between (e.g. embedded within or between) the interior surface portion 745 of anisotropic conductivity layer 728A and the dielectric layer 234. In one aspect, the electrodes 872 may sometimes be referred to being located at interface 235.

[00190] As shown in FIG. 1 1 , the electrodes 872 extend in a plane P4 generally parallel to the previously described plane P1 of the anisotropic conductivity layer 728A.

[00191] In this example arrangement, the patterned layer of electrodes 872 may overcome a presence of debris 208 and/or of formation irregularities 209 via a location in close proximity to the target locations (e.g. T1 , T2 in FIGS. 3, 6B) within passageway 1 19 of the consumable microfluidic receptacle 800. In some such examples, this location may enhance conveyance of charges from exterior surface portion 746 to interior surface portion 745 of anisotropic layer 728A at least because just a few conducive elements 134 under each electrode 872 may be sufficient to enable the voltage (e.g. V1 at charges 264B in FIG. 3A) at electrodes 872 correspond to (e.g. be equal to or close to) the voltage at the aligned electrodes 503 of the electrode control element 500, thereby providing a strong enough electric field (e.g. E in FIG. 1 A, 6B) to establish strong electrowetting pulling forces (e.g. F in FIG. 1 A, 6B) on droplet 129 to move into position T1 (FIG. 1 A, 6B).

[00192] FIG. 12 is a diagram including a side view schematically representing an example consumable microfluidic receptacle 850 and an electrode control element 500 prior to releasable contact with the receptacle 850. As shown in FIG. 12, in some examples the receptacle 850 comprises at least some of substantially the same features and attributes as the consumable receptacle 800 in FIG. 1 1 , except further comprising an additional layer 880 of electrodes 882 on an exterior surface 746 of the anisotropic conductivity layer 728A. Via this arrangement, the anisotropic conductivity layer 728A becomes sandwiched between first layer 870 of electrodes 872 and second layer 880 of electrodes 882. In this arrangement, the first layer 870 of electrodes 872 at interior surface portion 745 of anisotropic conductivity layer 728A is connected to, and in contact with, the dielectric layer 234. At this location, the electrodes 782 are in contact with (or electrically coupled to) first ends of the conducive elements 134 (e.g. conductive paths). As further shown in FIG. 12, the second layer 880 of electrodes 882 is formed at exterior surface portion 746 of the anisotropic conductivity layer 728A to be in contact with (or electrically coupled to) opposite second ends of the conductive elements 134 (e.g. conductive paths).

[00193] As shown in FIG. 12, the electrodes 872 extend in the previously described plane P4 generally parallel to the previously described plane P1 of the anisotropic conductivity layer 728A, while electrodes 882 may extend in the previously described plane P2.

[00194] In some examples, each respective first electrode 872 of layer 870 is in a one-to-one alignment with a respective one of the second electrodes 882 of layer 880, which provides an additional manner of ensuring conveyance of deposited charges (e.g. 264A in FIGS. 3, 6B) along an intended conveyance path from the electrode control element 500, through (e.g. across) the anisotropic conductivity layer 728A to one of the target locations (e.g. T1 , T2 in FIGS. 3, 6B) within passageway 1 19.

[00195] FIG. 13A is a block diagram schematically representing an example fluid operations engine 1200. In some examples, the fluid operations engine 1200 may form part of a control portion 1300, as later described in association with at least FIG. 13B, such as but not limited to comprising at least part of the instructions 131 1. In some examples, the fluid operations engine 1200 may be used to implement at least some of the various example devices and/or example methods of the present disclosure as previously described in association with FIGS. 1 -12 and/or as later described in association with FIGS. 13B-14. In some examples, the fluid operations engine 1200 (FIG. 13A) and/or control portion 1300 (FIG. 13B) may form part of, and/or be in communication with, an external charge applicator (e.g. 190, 280, 500) and/or a consumable microfluidic receptacle, such as the devices and methods described in association with at least FIGS. 1 -12.

[00196] As shown in FIG. 13A, in some examples the fluid operations engine 1200 may comprise a moving function 1202, a merging function 1204, and/or a splitting function 1206, which may track and/or control electrowetting-caused manipulation of droplets within a microfluidic device, such as moving, merging, and/or splitting, respectively.

[00197] In some examples, the fluid operations engine 1200 may comprise a charge control engine 1220 to track and/or control parameters associated with operation of an external charge applicator (e.g. 190 in FIG. 1 B, 280 in FIG. 3, 500 in FIGS. 6A-12) to build charges or neutralize charges on electrodes (e.g. 172, 782, 882) of a consumable microfluidic receptacle (of a microfluidic device), as well as to track and/or control the polarity of such charges. In some examples, charge control engine 1220 may track and/or control positioning of the external charge applicator and a consumable microfluidic receptacle relative to each other to implement such building or neutralizing of charges. In some examples, at least some of these aspects of the charge control engine 1220 may be implemented according to at least some of the example implementations described in association with at least FIGS. 1 -12 and 13B-14.

[00198] It will be understood that various functions and parameters of fluid operations engine 1200 may be operated interdependently and/or in coordination with each other, in at least some examples.

[00199] FIG. 13B is a block diagram schematically representing an example control portion 1300. In some examples, control portion 1300 provides one example implementation of a control portion forming a part of, implementing, and/or generally managing the example microfluidic devices, as well as the particular portions, components, external charge applicators, charge-receiving electrodes, electrode control elements, consumable microfluidic receptacle, dielectric layers, hydrophobic layers, substrates, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure in association with FIGS. 1 -13A and 13C-14. In some examples, control portion 1300 includes a controller 1302 and a memory 1310. In general terms, controller 1302 of control portion 1300 comprises at least one processor 1304 and associated memories. The controller 1302 is electrically couplable to, and in communication with, memory 1310 to generate control signals to direct operation of at least some of the example portions, components, etc. of the external charge applicators, charge-receiving electrodes, electrode control elements, consumable microfluidic receptacle, dielectric layers, hydrophobic layers, substrates, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure. In some examples, these generated control signals include, but are not limited to, employing instructions 1311 stored in memory 1310 to at least direct and manage microfluidic operations via electrowetting movement in the manner described in at least some examples of the present disclosure. In some instances, the controller 1302 or control portion 1300 may sometimes be referred to as being programmed to perform the above-identified actions, functions, etc.

[00200] In response to or based upon commands received via a user interface (e.g. user interface 1320 in FIG. 13C) and/or via machine readable instructions, controller 1302 generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller 1302 is embodied in a general purpose computing device while in some examples, controller 1302 is incorporated into or associated with at least some of the example microfluidic devices, as well as the particular portions, components, external charge applicators, charge-receiving electrodes, electrode control elements, consumable microfluidic receptacles, dielectric layers, hydrophobic layers, substrates, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, etc. as described throughout examples of the present disclosure.

[00201] For purposes of this application, in reference to the controller 1302, the term “processor” shall mean a presently developed or future developed processor (or processing resources) that executes machine readable instructions contained in a memory or that includes circuitry to perform computations. In some examples, execution of the machine readable instructions, such as those provided via memory 1310 of control portion 1300 cause the processor to perform the above-identified actions, such as operating controller 1302 to implement microfluidic operations, including causing electrowetting movement of droplets, via the various example implementations as generally described in (or consistent with) at least some examples of the present disclosure. The machine readable instructions may be loaded in a random access memory (RAM) for execution by the processor from their stored location in a read only memory (ROM), a mass storage device, or some other persistent storage (e.g., non-transitory tangible medium or non-volatile tangible medium), as represented by memory 1310. The machine readable instructions may include a sequence of instructions, a processor-executable machine learning model, or the like. In some examples, memory 1310 comprises a computer readable tangible medium providing nonvolatile storage of the machine readable instructions executable by a process of controller 1302. In some examples, the computer readable tangible medium may sometimes be referred to as, and/or comprise at least a portion of, a computer program product. In other examples, hard wired circuitry may be used in place of or in combination with machine readable instructions to implement the functions described. For example, controller 1302 may be embodied as part of at least one application-specific integrated circuit (ASIC), at least one field-programmable gate array (FPGA), and/or the like. In at least some examples, the controller 1302 is not limited to any specific combination of hardware circuitry and machine readable instructions, nor limited to any particular source for the machine readable instructions executed by the controller 1302.

[00202] In some examples, control portion 1300 may be entirely implemented within or by a stand-alone device.

[00203] In some examples, the control portion 1300 may be partially implemented in one of the example microfluidic operation devices (e.g. external charge applicator and/or consumable microfluidic receptacle) and partially implemented in a computing resource separate from, and independent of, the example microfluidic operation devices (e.g. external charge applicator and/or consumable microfluidic receptacle) but in communication with the example microfluidic operation devices. For instance, in some examples control portion 1300 may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion 1300 may be distributed or apportioned among multiple devices or resources such as among a server, a microfluidic operation device (e.g. external charge applicator and/or consumable microfluidic receptacle), and/or a user interface.

[00204] In some examples, control portion 1300 includes, and/or is in communication with, a user interface 1320 as shown in FIG. 12C. In some examples, user interface 1320 comprises a user interface or other display that provides for the simultaneous display, activation, and/or operation of at least some of the example microfluidic devices, as well as the particular portions, components, external charge applicator, charge-receiving electrodes, electrode control elements, consumable microfluidic receptacles, dielectric layers, hydrophobic layers, substrates, microfluidic operations, control portion, instructions, engines, functions, parameters, and/or methods, etc., as described in association with FIGS. 1 -13B and 14. In some examples, at least some portions or aspects of the user interface 1320 are provided via a graphical user interface (GUI), and may comprise a display 1324 and input 1322. [00205] FIG. 14 is a flow diagram of an example method 1400. In some examples, method 1400 may be performed via at least some of the devices, components, example microfluidic devices, external charge applicators, chargereceiving electrodes, electrode control elements, consumable microfluidic receptacles, dielectric layers, hydrophobic layers, substrates, microfluidic operations, instructions, control portions, engines, functions, parameters, and/or methods, etc. as previously described in association with at least FIGS. 1 -13C. In some examples, method 1400 may be performed via at least some of the devices, components, example microfluidic devices, as well as the particular portions, components, external charge applicators, charge-receiving electrodes, electrode control elements, consumable microfluidic receptacles, dielectric layers, hydrophobic layers, substrates, microfluidic operations, instructions, control portions, engines, functions, parameters, and/or methods, etc. other than those previously described in association with at least FIGS. 1 -13C.

[00206] In some examples, as shown at 1402 in FIG. 14 method 1400 may comprise placing a liquid droplet in a passageway between a first plate and a second plate of a replaceable fluid cavity, the second plate comprising a plurality of conductive paths spaced apart throughout a conductive-resistant portion with each conductive path oriented perpendicular to a plane through which second plate extends, the second plate including a first layer of spaced apart first electrodes extending parallel to the plane, with each first electrode electrically coupled relative to at least one conductive path. As further shown at 1404 in FIG. 14, method 1400 may comprise selectively applying charges from an external charge applicator, which is separate from the first electrodes, onto the respective first electrodes to pass through the conductive paths of the second plate to cause an electric field between the second plate and the first plate, to control electrowetting movement of the droplet through the passageway.

[00207] In some examples, the method 1400 may further comprise implementing the selective application of charges via the external charge applicator, which comprises at least one of: a non-contact charge depositing unit to selectively emit the charges as airborne charges of a selectable polarity; and an electrode control element comprising an array of individually controllable electrodes of a circuitry substrate and which is releasably engageable against the plurality of first electrodes to transmit the charges onto the respective first electrodes.

[00208] In some examples, the method 1400 may further comprise that the surface portion comprises at least one of: an exterior surface portion facing the external charge applicator; an interior surface portion facing the first plate; and an intermediate portion sandwiched between a first layer portion and a second layer portion of the conductive-resistant portion.

[00209] Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.