High throughput dielectrophoresis devices and microfluidic apparatuses with optimized electrode arrangements and wiring

Abstract

The application provides a dielectrophoresis device, comprising first electrodes arranged on one side of microfluidic channels, each microfluidic channel corresponding to one first electrode, and each first electrode being electrically connected to one first switch; and a plurality of second electrode groups arranged on the other side of the microfluidic channels, each second electrode group being electrically connected to one second switch, and each second electrode group comprising a plurality of second electrodes connected in series, and the plurality of second electrodes being respectively located in different microfluidic channels; wherein the activation and deactivation of each second electrode are controlled by the first switch of the first electrode corresponding to the microfluidic channel where the second electrode is located and the second switch of the second electrode group where the second electrode is located. The application greatly reduces the wiring complexity and the space required for wiring, and makes it possible to perform high-throughput single-cell operation in a microfluidic device based on metal / metal oxide electrodes.

Description

TECHNICAL FIELD

[0001] The present application relates to a dielectrophoresis device for micro-object manipulation, in particular to a high-throughput dielectrophoresis device with optimized electrode arrangement and wiring and a microfluidic device comprising the same. BACKGROUND

[0002] The development of biological and medical technology puts forward higher requirements for detecting and manipulating micro-nano-sized objects (such as biological cells and biological macromolecules). As a non-contact manipulation method, dielectrophoresis technology can achieve complex manipulation of micro-objects by using the dielectrophoresis force experienced by micro-objects in a non-uniform electric field. To achieve dielectrophoresis force, a plurality of electrodes need to be arranged near the micro-objects, and a non-uniform electric field is generated near the micro-objects by controlling the electrode switch.

[0003] Traditional metal electrodes can achieve precise and independent switch manipulation. For example, CN 109456874 A discloses a cell bidirectional dielectrophoresis single cell manipulation microfluidic chip, which sets a corresponding addressable electrode at each micro-trap, the micro-trap is arranged between a flat plate electrode and an addressable electrode (for example, both can be gold electrodes), by applying different frequency voltages to the addressable electrode, the target cell is captured by using positive dielectrophoresis, and then the target cell is pushed out of the micro-trap by controlling a single addressable electrode to generate negative dielectrophoresis. The addressable electrode is connected to an electrode driving input pin, and the flat plate electrode is welded to a printed circuit board by a gold wire. However, such a microfluidic chip is limited by wiring space and complexity because each addressable electrode is individually welded to the printed circuit board by a gold wire. It can only be applied to a microfluidic chip with a small number of micro-traps (i.e. a small number of addressable electrodes, such as tens or about one hundred). High-throughput single cell screening requires a microfluidic chip with thousands or even tens of thousands of micro-traps. If each electrode is individually welded to the printed circuit board by a metal wire and individually controlled, the wiring will be difficult to implement in the chip.

[0004] Optoelectronic tweezer (OET) technology, especially transistor-based optoelectronic tweezer technology, can achieve simultaneous manipulation of dielectrophoresis force on thousands or even tens of thousands of micro-traps. The typical structure of this type of optoelectronic tweezer device is to set a photosensitive material (such as a phototransistor array) between two glass plates coated with indium tin oxide (ITO). When a patterned light is irradiated on a specific area of the phototransistor array, the activated transistor allows current to pass through, thereby forming a non-uniform electric field in the microfluidic channel, generating a dielectrophoresis force capable of manipulating micro-objects. A bias voltage is usually applied between two electrodes, which is usually an alternating current AC.

[0005] For example, CN 107223074 B discloses a transistor photo tweezers and a microfluidic device thereof, each transistor structure contains a lateral transistor and a longitudinal transistor, in each transistor structure, a P-type base region surrounds an N-type emitter region, an N-type collector region surrounds the P-type base region, and the base region and the collector region each include a lateral portion and a longitudinal portion, compared with photo tweezers with only longitudinal transistors, the simultaneous generation of lateral current and longitudinal current at the same light intensity, the additional lateral transistor is said to increase the strength of the generated current, thereby allowing more robust control of micro-objects. However, photo tweezers devices based on photo transistors need to rely on silicon, germanium semiconductor processing technology, the process involved is complex, and the equipment is expensive.

[0006] Therefore, there is a need in the art for an improved dielectrophoresis device and corresponding microfluidic device to overcome the above-mentioned drawbacks in the prior art. SUMMARY

[0007] One aspect of the present application provides a dielectrophoresis device for a microfluidic device, the microfluidic device comprising at least two microfluidic channels, each microfluidic channel having an inlet and an outlet and comprising a plurality of microwells having an opening to the microfluidic channel, characterized in that the dielectrophoresis device comprises: a first electrode disposed on one side of the microfluidic channels, each microfluidic channel corresponding to one first electrode, the first electrode extending in the direction from the inlet to the outlet of the microfluidic channel, and each first electrode being electrically connected to one first switch; and a second electrode array disposed on the other side of the microfluidic channels, the second electrode array comprising a plurality of second electrode groups, each second electrode group being electrically connected to one second switch, each second electrode group comprising a plurality of second electrodes connected in series, the plurality of second electrodes being located in different microfluidic channels respectively, the second electrodes being point electrodes, the interior of each microwell corresponding to one second electrode as an interior electrode; wherein the activation and deactivation of each second electrode are controlled by the first switch of the first electrode corresponding to the microfluidic channel where the second electrode is located and the second switch of the second electrode group where the second electrode is located.

[0008] In some embodiments, each microwell corresponds to at least two second electrodes, respectively, the interior electrode and the exterior electrode opposite to the opening of the microwell, the interior electrode and the exterior electrode belonging to different second electrode groups.

[0009] In some embodiments, a second electrode is activated when both the first switch of the first electrode corresponding to the microfluidic channel where the second electrode is located and the second switch of the second electrode group where the second electrode is located are turned on, and the second electrode is deactivated when either of the first switch of the first electrode corresponding to the microfluidic channel where the second electrode is located and the second switch of the second electrode group where the second electrode is located is turned off.

[0010] In some embodiments, the dielectrophoretic device further comprises a third electrode array, the third electrode array comprising a plurality of third electrode groups, each microfluidic channel comprising at least one third electrode group, each third electrode group electrically connected to one third switch, each third electrode group comprising a plurality of third electrodes in series, and each third electrode being a point electrode, wherein activation and deactivation of each third electrode group is controlled by the first switch of the first electrode corresponding to the microfluidic channel where the third electrode group is located and the third switch of the third electrode group.

[0011] In some embodiments, each microwell corresponds to at least one third electrode, the third electrode being offset from the opening of the microwell and located in the microfluidic channel. In other embodiments, each microwell corresponds to two third electrodes, and the two third electrodes belong to different third electrode groups.

[0012] In some embodiments, a third electrode group is activated when both the first switch of the first electrode corresponding to the microfluidic channel where the third electrode group is located and the third switch of the third electrode group are open, and the third electrode group is deactivated when either of the first switch of the first electrode corresponding to the microfluidic channel where the third electrode group is located and the third switch of the third electrode group is closed.

[0013] In some embodiments, the first electrode and / or the second electrode is a metal electrode or a metal oxide electrode. In some embodiments, the third electrode is a metal electrode or a metal oxide electrode.

[0014] In some embodiments, the series or electrical connection is achieved by a metal material. In some embodiments, the second electrode array is disposed on an insulating layer, each second electrode passing through the insulating layer and being at least partially exposed to the microfluidic channel. In some embodiments, the metal material is located on the other side of the insulating layer relative to the microfluidic channel and is insulated from the microfluidic channel by the insulating layer. In some embodiments, the insulating layer is composed of silicon oxide or silicon nitride.

[0015] In some embodiments, the number of second electrodes is about 3,000 to about 9,000. In some embodiments, the total number of second electrodes and third electrodes is about 3,000 to about 9,000. In some embodiments, the number of second electrodes and / or third electrodes is about 6,000 to about 9,000, for example about 7,000.

[0016] In another aspect, the present application provides a microfluidic device comprising at least two microfluidic channels, each microfluidic channel having an inlet and an outlet and comprising a plurality of microwells having an opening to the microfluidic channel, and further comprising any one of the dielectrophoretic devices as described herein.

[0017] In some embodiments, the microfluidic device further comprises a printed circuit board to which the first switch, the second switch and the third switch are electrically connected, respectively. In some embodiments, the printed circuit board comprises at least one micro control unit (MCU) for controlling the opening and closing of the switches. In some embodiments, the printed circuit board comprises a plurality of multiplexing analog switches.

[0018] In some embodiments, each of the microfluidic channels in the microfluidic device comprises a first side wall and a second side wall opposite to and spaced apart from the first side wall, the microfluidic channel being formed between the first side wall and the second side wall, wherein a plurality of first extensions extending towards the second side wall without abutting the second side wall are formed on the first side wall, a plurality of second extensions extending towards the first side wall without abutting the first side wall are formed on the second side wall, the plurality of first extensions and the plurality of second extensions are alternately arranged in the microfluidic channel, and wherein the microwells are formed in at least one of the first extensions or at least one of the second extensions, the opening is positioned such that the fluid does not directly flow into each of the microwells.

[0019] By controlling the activation and deactivation of each second electrode through a secondary switch, the present application greatly reduces the complexity and space required for wiring the electrodes, making high-throughput single-cell manipulation possible in microfluidic devices based on metal / metal oxide electrodes. Furthermore, one or more groups of third electrodes can be provided in the microfluidic channel, the activation and deactivation of which are controlled through a secondary switch, thus increasing the number of electrodes without significantly increasing the wiring difficulty and space required. BRIEF DESCRIPTION OF DRAWINGS

[0020] The application will be described in greater detail with reference to the drawings. It should be noted that the illustrated arrangements are merely representative of embodiments of the application and that the elements in the drawings are not to scale with the actual elements, the number of actual elements can vary, the relative positions of actual elements are substantially maintained as shown, and certain elements are not shown. In the case of multiple embodiments, when one or more features described in a previous embodiment can also apply to another embodiment, for the sake of brevity, the one or more features that are repeatable are not repeated in the latter one or more embodiments, which should be understood to have described the repeatable features, unless otherwise stated. Those skilled in the art will realize, upon reading the present application, that one or more features shown in one figure can be combined with one or more features in another figure to construct one or more alternative embodiments not specifically shown in the drawings, which also form part of the present application.

[0021] Figure 1 A partial cross-sectional view of a microfluidic device according to one embodiment of the application is schematically shown along one of the microfluidic channels thereof.

[0022] Figure 2 A partial cross-sectional view of a microfluidic device according to one embodiment of the application is schematically shown along a cross-section of a microfluidic channel thereof.

[0023] Figure 3 A partial top view of a microfluidic device according to one embodiment of the application is schematically shown, showing only the electrode arrangement above the microfluidic channel and its electrical connections for the sake of clarity.

[0024] Figure 4 A partial top view of a microfluidic device according to one embodiment of the application is schematically shown, showing only the electrode arrangement below the microfluidic channel and its electrical connections for the sake of clarity.

[0025] Figure 5 A partial top view of a microfluidic device according to another embodiment of the application is schematically shown, showing the electrode arrangement below the microfluidic channel and its electrical connections.

[0026] Figure 6 A partial top view of a microfluidic device according to another embodiment of the application is schematically shown, showing the electrode arrangement below the microfluidic channel and its electrical connections.

[0027] Figure 7 An arrangement of a dielectrophoretic device according to one embodiment of the application in a microfluidic channel of an exemplary microfluidic device is schematically shown.

[0028] Figure 8FIG. 1 schematically illustrates a microfluidic channel design pattern of another microfluidic device to which a dielectrophoretic device according to one embodiment of the present application can be applied.

[0029] Figure 9 FIG. 2 schematically illustrates an arrangement of a dielectrophoretic device according to one embodiment of the present application in a microfluidic channel of another exemplary microfluidic device. DETAILED DESCRIPTION

[0030] The exemplary embodiments of this application are described in detail below with reference to the attached drawing figures, wherein:

[0031] Figure 1 FIG. 1 schematically illustrates a microfluidic channel design pattern of another microfluidic device to which a dielectrophoretic device according to one embodiment of the present application can be applied.

[0032] As Figure 2As shown, an array of second electrodes 112 is disposed on the other side of the microfluidic channel 152, the array of second electrodes comprising a plurality of second electrodes 112. A portion of each second electrode 112 is exposed in the microfluidic channel, thereby enabling direct contact with the microfluidic fluid. In this embodiment, the array of second electrodes 112 may be disposed on an insulating layer 106, with each second electrode 112 passing through the insulating layer 106. The insulating layer 106 may be made of, for example, silicon oxide or silicon nitride. The second electrode 112 is a point electrode, for example, circular or rectangular. The second electrode 112 may be made of the same material as the first electrode 104, for example, the second electrode 112 may be a metal or metal oxide electrode. Suitable materials for metal or metal oxide electrodes may be, for example, noble metals such as gold, silver, platinum, palladium, indium, iridium, etc.; metals such as copper, tin, antimony, iron, cobalt, nickel, chromium, titanium, manganese, etc.; or alloys such as platinum-barium, palladium-barium, iridium-tungsten-rhenium, iridium-barium-osmium, etc. In this embodiment, the second electrode 112 is made of indium tin oxide (ITO).

[0033] As described below, the second electrodes 112 are grouped in a specific manner in this invention, with each group individually connected to a switch. The second electrodes 112 within the same group are connected in series, which can be achieved by using a metallic material (e.g., molybdenum, aluminum, gold, or combinations thereof, not shown). The electrical connection between each group and the switch can also be achieved by using a metallic material (e.g., molybdenum, aluminum, gold, or combinations thereof). In this embodiment, the metallic material may be located in the wiring layer 108 below the insulating layer 106, insulated from the microfluidic channel 152 by the insulating layer 106. Optionally, in this embodiment, the insulating layer 106 is disposed on the substrate 110 (e.g., a glass substrate).

[0034] like Figure 2 and Figure 3 As shown, each microfluidic channel (such as 152a, 152b, 152c) corresponds to a first electrode (such as 104a, 104b, 104c). The microfluidic channels are separated by sidewalls 114. As shown, the first electrode 104 may not span the entire channel, but may be located at the center of the channel. The first electrode 104 extends along the length of the channel, and the distance of extension is not particularly limited. For example, the first electrode 104 may extend along the entire length of the channel. In this embodiment, the second electrode 112 is positioned close to the sidewall 114, and thus close to the micropore 126 formed on the sidewall (see Figure 104a, 104b, 104c). Figure 4 The bottom of the channel. The position of the second electrode 112 can also be set at other positions in the channel as needed. The number of second electrodes 112 in each channel 152 is shown as one, but in other embodiments (described below), the number can vary. No electrical connection is formed between the second electrodes 112 in different channels 152. Figure 3As shown, in this embodiment, each first electrode 104 is individually electrically connected to one first switch 120 (as shown by first switches 120a, 120b, and 120c), and no electrical connection is formed between the corresponding first electrodes 104 of each channel 152.

[0035] Figure 4 is a partial view of the arrangement of second electrodes 112 and their electrical connections in a microfluidic device according to an embodiment of the present application. As shown, there are three channels 152a, 152b, and 152c, each having a plurality of microwells 126 defined by a fence 124 extending from the side wall 114 into the channel. Preferably, the microwells 126 are sized to be comparable to the size of a cell, for example, about 15 to about 30 microns, so that the microwells 126 can only hold a single cell. The microwells 126 have an opening to the fluid channel 152, allowing cells or other micro-objects (such as labeled fluorescent microspheres) to enter and exit the microwells 126. As shown, the openings of the microwells 126 can be arranged to not directly face the direction of fluid flow (as indicated by the arrows).

[0036] In this embodiment, the second electrodes 112 are arranged to correspond to the bottoms of the microwells 126. The second electrodes 112 are grouped into different second electrode groups 122 (as shown by the dashed boxes) according to their electrical connections. Each second electrode group 122 (shown as 122a, 122b, 122c, and 122d) is electrically connected to one second switch 130 (shown as second switches 130a, 130b, 130c, and 130d) and is individually controlled by the corresponding second switch 130. Each second electrode group 122 includes a plurality of second electrodes 112 connected in series, and the series of second electrodes 112 are respectively located in different microfluidic channels 152. Specifically, the second electrodes 112 (Al) in channel 152a, the second electrodes 112 (A2) in channel 152b, and the second electrodes 112 (A3) in channel 152c are connected in series by a wire 128 (for example, a molybdenum wire, as shown by the dashed lines) to form the second electrode group 122a. Similarly, B1 / B2 / B3 are connected in series to form the second electrode group 122b, C1 / C2 / C3 are connected in series to form the second electrode group 122c, and D1 / D2 / D3 are connected in series to form the second electrode group 122d. However, the second electrodes 112 in the same channel (for example, 152a) (for example, numbered Al, Bl, Cl, and Dl) are not electrically connected by a wire.

[0037] In this embodiment, the activation and deactivation of each second electrode 112 are controlled by the first switch (120a) of the first electrode (104a) corresponding to the microfluidic channel (152a) where the second electrode 112 (e.g., A1) is located, and the second switch (e.g., 130a) of the second electrode group (122a) where the second electrode 112 (e.g., A1) is located. For example, the second electrode A1 is activated when both the first switch 120a of the first electrode 104a corresponding to the microfluidic channel 152a where the second electrode A1 is located and the second switch 130a of the second electrode group 122a where the second electrode A1 is located are open, and the second electrode A1 is deactivated when either the first switch 120a of the first electrode 104a corresponding to the microfluidic channel 152a where the second electrode A1 is located or the second switch 130a of the second electrode group 122a where the second electrode A1 is located is closed. Therefore, the activation of each second electrode 112 is controlled by two levels of switches. During operation, controlling the opening or closing of the two-stage switch can apply a voltage of a specific frequency to the corresponding second electrode 112. Micro-objects (such as cells) inside or near the micropore 126 will be subjected to electric fields in different directions, generating positive or negative dielectric force (i.e., attraction or push), thereby manipulating the micro-objects to enter and exit the micropore 126.

[0038] like Figure 5 As shown, in another embodiment, each micropore 126 corresponds to at least two second electrodes: an internal second electrode 112 inside the micropore 126 and an external second electrode 112 opposite to the opening of the micropore. The internal second electrode 112 and the external second electrode 112 belong to different second electrode groups. The arrangement, electrical connection method, and activation / deactivation method of the internal second electrode 112 are consistent with those described above. Figure 4The same is described. Similar to the internal second electrodes 112, the external second electrodes 112 are grouped into different second electrode groups 132 (shown as dashed boxes) according to their electrical connection. Each second electrode group 132 (shown as 132a, 132b, 132c, and 132d) is electrically connected to one second switch 140 (shown as second switches 140a, 140b, 140c, and 140d) and is controlled by the corresponding second switch 140 individually. Each second electrode group 132 includes a plurality of external second electrodes 112 in series, and the series of external second electrodes 112 are located in different microfluidic channels 152 respectively. Specifically, the external second electrodes 112 (E2) in channel 152b and the external second electrodes 112 (E3) in channel 152c are in series through a wire 134 (e.g., a molybdenum wire, as shown by the solid line), forming the second electrode group 132a (the external second electrodes in channel 152a are not shown). Similarly, F2 / F3 are in series to form the second electrode group 132b, G2 / G3 are in series to form the second electrode group 132c, and H2 / H3 are in series to form the second electrode group 132d. However, the external second electrodes 112 in the same channel (e.g., 152b) (e.g., numbered E2, F2, G2, and H2) are not electrically connected through the wire. The second electrode group 122 and the second electrode group 132 are also not electrically connected through the wire.

[0039] In this embodiment, the activation and deactivation of each internal second electrode 112 is controlled by the first switch (120a) of the first electrode (e.g., 104a) corresponding to the microfluidic channel (e.g., 152a) where the internal second electrode 112 (e.g., A1) is located and the second switch (e.g., 130a) of the second electrode group (e.g., 122a) where the internal second electrode 112 (e.g., A1) is located. Similarly, the activation and deactivation of each external second electrode 112 is controlled by the first switch (120b) of the first electrode (e.g., 104b) corresponding to the microfluidic channel (e.g., 152b) where the external second electrode 112 (e.g., E2) is located and the second switch (e.g., 140a) of the second electrode group (e.g., 132a) where the external second electrode 112 (e.g., E2) is located. For example, the external second electrode E2 is activated when both the first switch 120b of the first electrode 104b corresponding to the microfluidic channel 152b where the external second electrode E2 is located and the second switch 140a of the second electrode group 132a where the external second electrode E2 is located are open, and the external second electrode E2 is deactivated when either of the first switch 120b of the first electrode 104b corresponding to the microfluidic channel 152b where the external second electrode E2 is located and the second switch 140a of the second electrode group 132a where the external second electrode E2 is located is closed. Therefore, the activation of each external second electrode 112 is controlled by two-stage switching.

[0040] The additional external second electrodes 112 opposite the openings allow for the application of a voltage of a particular frequency to the corresponding second electrodes 112 to control the activation of each second electrode 112 independently to generate a positive or negative dielectrophoretic force to push or attract a micro-object into or out of the microwells 126, thus making the manipulation of the micro-objects more convenient, accurate and with a wider range of manipulations. The voltage used can be an alternating current (AC). The peak voltage of the AC can be between about 1 Vppk and about 50 Vppk, and the frequency can be between about 10 kHz and about 10 MHz. The AC can be a square wave, a sine wave or a triangular wave.

[0041] Figure 6 An electrode distribution diagram of the bottom of the channels in another embodiment is shown. This embodiment is similar to the embodiment shown in FIG. 2, but with the addition of third electrodes 142 between the internal second electrodes 112 and the external second electrodes 112 in the channels. Figure 5 The embodiment shown in FIG. 3 is similar to the embodiment shown in FIG. 2, but with the addition of third electrodes 142 between the internal second electrodes 112 and the external second electrodes 112 in the channels. The third electrodes 142 form a third electrode array, which includes a plurality of third electrode groups, such as third electrode groups 146a, 146b and 146c. Each microfluidic channel 152 includes at least one third electrode group 146, as shown in FIG. 3, where channel 152a includes third electrode group 146a, channel 152b includes third electrode group 146b, and channel 152c includes third electrode group 146c. Each third electrode group 146 is electrically connected to a third switch 150, as shown in FIG. 3, where third electrode group 146a is electrically connected to third switch 150a, third electrode group 146b is electrically connected to third switch 150b, and third electrode group 146c is electrically connected to third switch 150c. Each third electrode group 146 includes a plurality of third electrodes 142, and the third electrodes are point electrodes. The third electrodes in each third electrode group 146 are connected in series by a metal material 144, such as a molybdenum wire. As shown in FIG. 3, unlike the electrical connections of the second electrodes 112, the third electrodes 142 in each third electrode group 146 are in the same microfluidic channel 152. For example, third electrodes Ml, M2, M3 and M4 in third electrode group 146a are all in channel 152a. Similarly, third electrodes Nl, N2, N3 and N4 in third electrode group 146b are all in channel 152b, and third electrodes Pl, P2, P3 and P4 in third electrode group 146c are all in channel 152c. The third electrodes 142 in different channels 152 are not electrically connected by a metal wire, such as between Ml and Nl, or between Nl and Pl. The third electrode groups 146 are also not electrically connected to the second electrode groups 122 or 132 by a metal wire.

[0042] As shown, the third electrode set 146 is generally between the second electrodes 112 located within the microwells 126 and the second electrodes 112 located outside the microwells 126 and corresponding to the microwell openings, and is preferably located at a middle position of the microfluidic channel 152. Thus, the third electrodes 142 can be offset from the openings of the microwells 126. The third electrode set 146 has a direction of extension that is generally the same as the first electrodes 104. The number of third electrodes 142 can be equal to or less than the number of second electrodes 112 (one second electrode per microwell), or equal to or less than the number of second electrodes 112 located within the microwells 126 (at least two second electrodes per microwell, including the second electrodes located within the microwells). For example, two or more microwells 126 share one third electrode 142, and thus the number of third electrodes 142 can be about 1 / 2 to about 1 / 4 of the number of inner second electrodes 112, or less. In this embodiment, the number of third electrodes 142 is equal to the number of second electrodes 112 or the number of inner second electrodes 112. The material of the third electrodes 142 can be the same as the material of the first electrodes 104 or the second electrodes 112.

[0043] The activation and deactivation of each third electrode set 146 is controlled by the first switch 120 of the first electrode 104 corresponding to the microfluidic channel 152 where the third electrode set 146 is located and the third switch 150 of the third electrode set 146. For example, the third electrode set 146a is activated when both the first switch 120a of the first electrode 104a corresponding to the microfluidic channel 152a where the third electrode set 146a is located and the third switch 150a of the third electrode set 146a are turned on, and the third electrode set 146a is deactivated when either of the first switch 120a of the first electrode 104a corresponding to the microfluidic channel 152a where the third electrode set 146a is located and the third switch 150a of the third electrode set 146a is turned off. Thus, similarly, the activation of each third electrode 142 is controlled by two-level switches.

[0044] Figure 7A schematic diagram showing the microfluidic channel design and electrode distribution in one exemplary microfluidic device suitable for use with the dielectrophoretic apparatus of the present application. The microfluidic device has a first opening (e.g., inlet 103) and a second opening (e.g., outlet 105) through which a fluid containing micro-objects (e.g., cells) flows in through inlet 103, through microfluidic channels 152a-152e, where biological analysis is performed, and out through outlet 105. The top of the microfluidic channels has first electrodes and their switches as described herein, which are not shown in the figure. As shown, each microwell 126 has an internal second electrode 112 corresponding to its bottom (as shown by the square shading within the microwell) and an external second electrode 112 opposite its opening (as shown by the circular shading). In each channel 152, third electrodes 142 are serially connected to form a third electrode group 146 (as shown by the dotted square box). Internal second electrodes 112 in different channels 152 are serially connected to form a second electrode group 122 (as shown by the dashed square box), and external second electrodes 112 in different channels 152 are serially connected to form a second electrode group 132 (as shown by the dashed circle). Each electrode group 122, 132, 146 is connected to a respective switch in the manner described previously with respect to FIG. 1. Figure 6

[0045] Figure 8 A schematic diagram showing the microfluidic channel design in another exemplary microfluidic device suitable for use with the dielectrophoretic apparatus of the present application. The microfluidic channel includes a first sidewall 202 and a second sidewall 204 opposite and spaced apart from the first sidewall 202. The microfluidic channel is formed between the first sidewall 202 and the second sidewall 204. Fluid flows into one end of the microfluidic channel in the direction indicated by arrow F, then flows between the first sidewall 202 and the second sidewall 204, and finally flows out of the other end of the microfluidic channel. The first sidewall 202 has a plurality of first extensions 206 extending toward the second sidewall 204 formed thereon. The second sidewall 204 has a plurality of second extensions 208 extending toward the first sidewall 202 formed thereon. The first extensions 206 and the second extensions 208 are alternately arranged in the microfluidic channel. The first extensions 206 extend from the first sidewall 202 but do not abut the second sidewall 204, thereby changing the flow direction of the fluid. The second extensions 208 extend from the second sidewall 204 but do not abut the first sidewall 202, thereby again changing the flow direction of the fluid. The first extensions 206 are spaced apart from adjacent second extensions 208 to form flow passages for the fluid to flow between the first extensions 206 and the adjacent second extensions 208. As the fluid flows between the first sidewall 202 and the second sidewall 204, it flows alternately through the first extensions 206 and the second extensions 208, thereby being constantly changed in flow direction by the first extensions 206 and the second extensions 208 (e.g., as indicated by direction F').

[0046] ​Micro-wells 226 are formed on the first and second extensions 206, 208 and are configured to hold micro-objects (e.g., cells, microspheres). The micro-wells 226 have an opening to allow the micro-objects to enter. The micro-wells 226 extend from the opening to form a cavity to hold the micro-objects. Each micro-well is provided with only one opening so that fluid or micro-objects in the fluid can only enter or exit the micro-well through the opening. The opening of the micro-well 226 is positioned so that fluid does not directly flow into each micro-well 226. For example, the opening of the micro-well 226 is oriented perpendicular to the flow direction F’ of the fluid at the opening. More details about the microfluidic channel design can be found in Chinese Invention Patent Application No. CN 202111663402.6, filed on December 31, 2021, the entire contents of which are incorporated herein by reference.

[0047] Figure 9 A microfluidic device with a microfluidic channel design is shown, which uses one exemplary dielectrophoresis device provided by the present application. As shown, the microfluidic device has a plurality (6 shown) of microfluidic channels 200, each of which has a plurality of micro-wells 226. The microfluidic channels 200 are connected to a fluid inlet 202 and a fluid outlet 204. The microfluidic channels 200 are connected to a fluid inlet 202 and a fluid outlet 204. Figure 8 A schematic diagram of the electrode distribution of a microfluidic device with a microfluidic channel design is shown, which uses one exemplary dielectrophoresis device provided by the present application. As shown, the microfluidic device has a plurality (6 shown) of microfluidic channels 200, each of which has a plurality of micro-wells 226. The microfluidic channels 200 are connected to a fluid inlet 202 and a fluid outlet 204. The microfluidic channels 200 are connected to a fluid inlet 202 and a fluid outlet 204. Figure 8 As shown, for each micro-well 226, there are four electrodes, which are the inner and outer second electrodes 112 corresponding to the micro-well 226, and the third electrodes 142a and 142b disposed in the microfluidic channel corresponding to the fluid flow direction change. The third electrodes 142a in the same channel are connected in series to form a third electrode group 146a, and the third electrodes 142b in the same channel are connected in series to form a third electrode group 146b. Thus, the same channel can have two independent third electrode groups, and are respectively connected to different third switches. The inner second electrodes 112 in different channels are connected in series to form a second electrode group 122, and the outer second electrodes 112 in different channels are connected in series to form a second electrode group 132, wherein the second electrode groups 122 and 132 are insulated from each other and are respectively connected to second switches. Each electrode group 122, 132, 146 is connected to the respective switch in the manner described earlier with respect to the dielectrophoresis device. Figure 6 As shown, for each micro-well 226, there are four electrodes, which are the inner and outer second electrodes 112 corresponding to the micro-well 226, and the third electrodes 142a and 142b disposed in the microfluidic channel corresponding to the fluid flow direction change. The third electrodes 142a in the same channel are connected in series to form a third electrode group 146a, and the third electrodes 142b in the same channel are connected in series to form a third electrode group 146b. Thus, the same channel can have two independent third electrode groups, and are respectively connected to different third switches. The inner second electrodes 112 in different channels are connected in series to form a second electrode group 122, and the outer second electrodes 112 in different channels are connected in series to form a second electrode group 132, wherein the second electrode groups 122 and 132 are insulated from each other and are respectively connected to second switches. Each electrode group 122, 132, 146 is connected to the respective switch in the manner described earlier with respect to the dielectrophoresis device.

[0048] It is noted that the number of channels 152, the number of second electrodes 112, the second electrode groups 122, 132 (and the corresponding second switches 130, 140), the number of third electrode groups 146 (and the corresponding third switches 150) can vary without being limited to the numbers shown herein. In this regard, the electrode arrangement and its electrical connection method according to the present application are particularly suitable for high-throughput single-cell manipulation, for example, for a microfluidic device having about 3,000 to about 9,000 (or even more) microwells. When one second electrode is provided for each microwell, the number of second electrodes can be about 3,000 to about 9,000, or even more. By controlling the activation and deactivation of each second electrode through a secondary switch, the complexity of the electrode wiring and the space required for the wiring are greatly reduced, making high-throughput single-cell manipulation possible in a microfluidic device based on metal / metal oxide electrodes. Moreover, in the presence of the third electrode groups, by controlling the activation and deactivation of each third electrode group through a secondary switch, the complexity of the electrode wiring and the space required for the wiring can not be significantly increased. It is also noted that although the two-level switching is shown and described herein, it is understood that the present application is not limited thereto, but the number of switching levels can be increased, for example, to three levels, four levels, or higher, such that the activation of a single electrode or electrode group is controlled by more switches, thereby further simplifying the complexity of the wiring.

[0049] Another aspect of the present application provides a microfluidic device. The microfluidic device includes at least two microfluidic channels and includes a dielectrophoresis apparatus as described herein. In some embodiments, the microfluidic device further includes a printed circuit board to which the first switches 120, the second switches 130, 140, and the third switches 150 are electrically connected, respectively. For example, the printed circuit board can include one or more micro control units (MCU) for controlling the opening and closing of the switches. In one embodiment, any one or all of the first switches 120, the second switches 130, 140, and the third switches 150 can be implemented by means of a multiplexing analog switch. Moreover, in one embodiment of the microfluidic device, the first, second, and third electrodes described herein can be independently numbered and controlled for activation and deactivation by computer software. In one embodiment, the microfluidic device further includes an image acquisition and analysis device for acquiring images in the microfluidic channels and analyzing the images to enable corresponding operations of the microfluidic device by computer software.

[0050] The above described are representative examples of embodiments of the present application and are provided for illustrative purposes only. The present application contemplates that one or more of the technical features used in one embodiment can be added to another embodiment, without departing from the objectives of the embodiments, to form improved or alternative embodiments. Similarly, one or more of the technical features used in one embodiment can be omitted or replaced, without departing from the objectives of the embodiments, to form alternative or simplified embodiments. Furthermore, one or more of the technical features used in one embodiment can be combined with one or more technical features in another embodiment, without departing from the objectives of the embodiments, to form improved or alternative embodiments. The present application is intended to encompass all such improved, alternative, simplified technical solutions.

Claims

1. A dielectrophoresis apparatus for use in a microfluidic device, the microfluidic device comprising at least two microfluidic channels, each microfluidic channel having an inlet and an outlet and including a plurality of micropores, the micropores having openings leading to the microfluidic channels, characterized in that, The dielectrophoresis apparatus includes: A first electrode is disposed on one side of the microfluidic channel, with one first electrode corresponding to each microfluidic channel. The first electrode extends along the direction from the inlet to the outlet of the microfluidic channel, and each first electrode is electrically connected to a first switch; and A second electrode array is disposed on the other side of the microfluidic channel. The second electrode array includes a plurality of second electrode groups. Each second electrode group is electrically connected to a second switch. Each second electrode group includes a plurality of second electrodes connected in series. The plurality of second electrodes are located in different microfluidic channels. The second electrodes are point electrodes. Each micropore corresponds to a second electrode that serves as an internal electrode. The activation and deactivation of each second electrode are controlled by the first switch of the first electrode corresponding to the microfluidic channel in which the second electrode is located and the second switch of the second electrode group in which the second electrode is located; and The second electrode in the same channel is not electrically connected via a metal wire.

2. The dielectrophoresis apparatus according to claim 1, characterized in that, Each micropore corresponds to at least two second electrodes, namely the internal electrode and the external electrode opposite to the opening of the micropore. The internal electrode and the external electrode belong to different second electrode groups, and the different second electrode groups are not electrically connected by metal wires.

3. The dielectrophoresis apparatus according to claim 1 or 2, characterized in that, The dielectrophoresis apparatus further includes a third electrode array, which includes a plurality of third electrode groups. Each microfluidic channel includes at least one third electrode group. Each third electrode group is electrically connected to a third switch. Each third electrode group includes a plurality of third electrodes connected in series, and the third electrodes are point electrodes. The activation and deactivation of each third electrode group are controlled by the first switch of the first electrode corresponding to the microfluidic channel where the third electrode group is located and the third switch of the third electrode group. The third electrode group and the second electrode group are not electrically connected by metal wires.

4. The dielectrophoresis apparatus according to claim 3, characterized in that, Each micropore corresponds to at least one third electrode, which is offset from the opening of the micropore and located in the microfluidic channel.

5. The dielectrophoresis apparatus according to claim 4, characterized in that, Each micropore corresponds to two third electrodes, and the two third electrodes belong to different third electrode groups.

6. The dielectrophoresis apparatus according to claim 3, characterized in that, The first electrode, the second electrode, and the third electrode are independently metal electrodes or metal oxide electrodes.

7. The dielectrophoresis apparatus according to claim 1, characterized in that, The second electrode array is disposed on an insulating layer, with each second electrode passing through the insulating layer and at least partially exposed to the microfluidic channel.

8. The dielectrophoresis apparatus according to claim 7, characterized in that, The insulating layer is composed of silicon oxide or silicon nitride.

9. The dielectrophoresis apparatus according to claim 7, characterized in that, The series or electrical connection is achieved through a metal material connection.

10. The dielectrophoresis apparatus according to claim 9, characterized in that, The metallic material is located on the other side of the insulating layer opposite to the microfluidic channel and is insulated from the microfluidic channel by the insulating layer.

11. The dielectrophoresis apparatus according to claim 1, characterized in that, The number of the second electrodes is between 3,000 and 9,000.

12. A microfluidic device comprising at least two microfluidic channels, each microfluidic channel having an inlet and an outlet and including a plurality of micropores, said micropores having openings leading to the microfluidic channels, characterized in that, The microfluidic device further includes the dielectrophoresis apparatus according to any one of claims 1 to 11.

13. The microfluidic device according to claim 12, characterized in that, The microfluidic device also includes a printed circuit board, with the first switch, the second switch, and the third switch electrically connected to the printed circuit board.

14. The microfluidic device according to claim 13, characterized in that, The printed circuit board includes at least one microcontroller unit for controlling the opening and closing of each switch.

15. The microfluidic device according to claim 13, characterized in that, The printed circuit board includes a plurality of multiplexed analog switches.

16. The microfluidic device according to claim 12, characterized in that, Each of the microfluidic channels includes a first sidewall and a second sidewall opposite to and spaced apart from the first sidewall, the microfluidic channel being formed between the first sidewall and the second sidewall. The first sidewall has a plurality of first extensions extending toward but not abutting the second sidewall, and the second sidewall has a plurality of second extensions extending toward but not abutting the first sidewall. The plurality of first extensions and the plurality of second extensions are arranged alternately in the microfluidic channel. The micropores are formed in at least one first extension or at least one second extension, and the openings are positioned to prevent the fluid from flowing directly into each of the micropores.

Images