CN115825203A - Dielectrophoresis force testing chip, testing device and testing method - Google Patents

Abstract

The invention relates to the technical field of optical tweezers testing dielectrophoresis force, and discloses a dielectrophoresis force testing chip, a testing device and a testing method. The invention can realize the analysis of the influence of the mutual inductance effect between different electrode pairs on the chip pairing efficiency and improve the pairing performance of the power-assisted chip by testing the dielectrophoresis force borne by the microspheres between different electrode pairs.

Description

A dielectrophoretic force test chip, test device and test method

technical field

The invention relates to the technical field of optical tweezers testing dielectrophoretic force, in particular to a dielectrophoretic force testing chip, a testing device and a testing method.

Background technique

The research on the single-cell paired microfluidic chip platform is of great significance to the research of precise cell fusion, single-cell interaction and single-cell sequencing. Research has shown that the occurrence of most diseases involves at least one type of communication problem between cells. At present, the research on the interaction between cells is still focused on the cell population level, and what is obtained is the overall average effect displayed by many cells. However, studying cell-cell interactions at the single-cell level allows the observation of some indistinct cellular responses that are masked at the aggregate level. It is difficult to obtain an isolated pair of single cells in vivo. Therefore, establishing a fast and simple method for single cell capture pairing can provide a powerful research platform for related biomedical fields. Among them, dielectrophoresis (dielectrophoresis, DEP) is a method in which neutral particles are controlled by the dielectric properties of neutral particles to move to a high electric field by a positive DEP force or to a low electric field by a negative DEP force in a non-uniform electric field. , so as to realize the manipulation of dielectric particles. By rationally designing and fabricating a microfluidic chip based on the DEP principle, we can achieve effective high-throughput single-cell pairing. For example, Cheng Xin's research group at Southern University of Science and Technology has developed a "planar" DEP single-cell paired chip, which integrates two pairs of interdigitated microelectrode structures in the same plane, combined with microcavity arrays, micro baffles and other structures, in turn. When two pairs of interdigitated electrodes were energized, the two kinds of cells were sequentially trapped in adjacent single-cell-sized microcavity arrays under the action of DEP, and finally formed an array of single-cell pairs, with a pairing efficiency of 74%. The Yasukawa research group of the University of Hyogo, Japan reported a "vertical" single-cell paired microfluidic device based on the DEP method, which uses the positive dielectrophoresis generated by the top ITO electrode and the bottom patterned microelectrode The two kinds of cells are sequentially captured in the microcavity array to achieve high-throughput single-cell pairing, with a pairing efficiency of 44%. In these different chip structures, the mutual inductance effect between different electrode pairs is a key factor affecting the pairing rate. Therefore, in the process of chip structure design and optimization, finding a method that can accurately analyze the mutual inductance effect in the chip structure is very helpful to improve the pairing performance of the chip.

Therefore, those skilled in the art are devoting themselves to developing a dielectrophoretic test chip, a test device and a test method, so as to realize the influence and analysis of the mutual inductance effect between different electrode pairs on the chip pairing efficiency.

Contents of the invention

In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to provide a dielectrophoretic force test chip, a test device and a test method to realize the influence and analysis of the mutual inductance effect between different electrode pairs on chip pairing efficiency.

In order to achieve the above object, the present invention provides a dielectrophoretic test chip, which includes a base layer, on which an electrode layer is arranged, and the electrode layer includes at least one first interdigitated electrode pair and at least one second fork For the pair of finger electrodes, the pole plates of the first interdigital electrode pair and the second interdigital electrode pair are vertically arranged. The setting of two electrode pairs can energize one of the electrode pairs, thereby forming a non-uniform electric field between the two electrode pairs, and the dielectrophoretic force in the electric field of the microspheres in the electric field can move. By observing the movement direction of the microspheres and The distance can measure the dielectrophoretic force on the microsphere and the difference in the dielectrophoretic force on the microsphere caused by different mutual inductance electric fields. The vertical setting of the polar plate can facilitate positioning on the one hand, and on the other hand, it is more convenient to observe the trajectory of the microspheres, which is convenient for subsequent calculations.

Preferably, the first interdigital electrode pair and the second interdigital electrode pair are arranged in pairs, and one first interdigital electrode pair and one second interdigital electrode pair form an interdigital electrode group. Two electrode pairs are arranged in groups, and a group of electrode pairs can form an electric field.

Preferably, above the electrode layer is a negative glue layer, and several microcavities are arranged on the negative glue layer, and a single microcavity is connected to the two paired plates of any first interdigitated electrode pair, or connected to Any second interdigitated electrode pair refers to two paired plates. The setting of the microcavity facilitates the formation of multiple independent electric fields.

Preferably, several microcavities are arranged in a horizontal and vertical array, thereby forming a plurality of regular electric fields, which is convenient for testing and observation.

Preferably, the cross-section of the microcavity is circular, with a diameter of 15-25 microns and a depth of 8-15 microns.

Preferably, the first interdigitated electrode pair includes a first electrode plate and a second electrode plate, and the first electrode plates of each first interdigitated electrode pair are connected to each other;

A first conductive strip is provided on the negative adhesive layer, and the first conductive strip is connected to the second plate of each of the first interdigitated electrode pairs;

The second interdigitated electrode pair includes a third pole plate and a fourth pole plate;

A second conductive strip is provided on the negative adhesive layer, and the second conductive strip is connected to the third plate of each of the second interdigitated electrode pairs;

A third conductive strip is also arranged on the negative adhesive layer, and the third conductive strip is connected to the fourth electrode plate of each second interdigitated electrode pair.

Preferably, a positioning block is provided on the negative adhesive layer, and a positioning block is provided at the front and back of any of the interdigital electrode groups.

The present invention also provides a dielectrophoretic test device, which includes the above-mentioned dielectrophoretic test chip.

Preferably, it also includes a clamp, the clamp includes a glass slide base plate, and a front clamping wall and a rear clamping wall are arranged on the slide glass base plate, and the front clamping wall and the rear clamping wall are surrounded by a gap with a gap at the contact point. A cavity, the dielectrophoretic test chip is inserted into the gap after packaging. The bottom of the fixture adopts a glass slide base plate, which is convenient for the laser beam (optical trap) to shine into the cavity, capture the microspheres, and facilitate observation at the same time.

The present invention also provides a method for testing dielectrophoretic force, using the above-mentioned dielectrophoretic force chip or dielectrophoretic force testing device, comprising the following steps:

S1: Standing the dielectrophoretic force chip in a cavity, the bottom of the cavity is a glass slide bottom plate;

S2: adding the microsphere solution into the cavity;

S3: Use two beams of light traps to trap microspheres above the first pair of interdigitated electrodes and the second pair of interdigitated electrodes, each beam of light traps captures at least one microsphere; the height of the captured microspheres is on the same plane;

S4: Apply a sinusoidal electrical signal to the first interdigitated electrode pair, and the microspheres are subjected to dielectrophoretic force to move laterally in the optical trap;

S5: Observe the moving direction of the microspheres, determine the direction of the dielectrophoretic force, and analyze the dielectrophoretic force and the mutual inductance electric field on the microspheres that are subjected to the applied electricity by testing and calculating the transverse optical trap force received by the two microspheres. The difference in the size of the dielectrophoretic force.

The beneficial effects of the present invention are: the present invention can realize the influence analysis of the mutual inductance effect between different electrode pairs on the chip pairing efficiency by testing the dielectrophoretic force on the microspheres between different electrode pairs, and help improve the chip pairing performance.

Description of drawings

Fig. 1 is a schematic structural diagram of a dielectrophoretic force testing device according to a specific embodiment of the present invention.

Fig. 2 is a schematic diagram of the electrode layer structure of a dielectrophoretic test chip according to a specific embodiment of the present invention.

Fig. 3 is a front structural schematic diagram of a dielectrophoretic force testing device according to a specific embodiment of the present invention.

FIG. 4 is a schematic diagram of an enlarged structure at point A in FIG. 3 .

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation or in a specific way construction and operation, therefore, should not be construed as limiting the invention. The terms "first", "second", "third", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

As shown in Fig. 1 and Fig. 2, a kind of dielectrophoretic test chip comprises base layer 1, and electrode layer 2 is arranged on base layer 1, and electrode layer 2 comprises at least one first interdigitated electrode pair 21 and at least one second The interdigital electrode pair 22 , the pole plates of the first interdigital electrode pair 21 and the second interdigital electrode pair 22 are all arranged vertically. In the present invention, the base layer 1 is made of a glass substrate, and the interdigital electrodes on the base layer 1 are specifically patterned ITO electrodes. In this embodiment, there are three pairs of first interdigital electrode pairs 21 and three pairs of second interdigital electrode pairs 22 . Using the dielectrophoretic force test chip in this application, by energizing the first interdigitated electrode pair 21, the microspheres in the microsphere solution where the electrodes are located are subjected to dielectrophoretic force, thereby generating motion, and the pole plates are vertically arranged , which can facilitate the observation of the direction and distance of the microsphere movement.

The first interdigital electrode pair 21 and the second interdigital electrode pair 22 are arranged in pairs, and one first interdigital electrode pair 21 and one second interdigital electrode pair 22 form an interdigital electrode group. Therefore, in this embodiment, there are 3 interdigitated electrode groups, so that multiple groups of observation can be performed.

The top of the electrode layer 2 is a negative glue layer 3, and the negative glue layer 3 is provided with several microcavities 30, as shown in Figures 3 and 4, a single microcavity 30 communicates with any pair of two first interdigitated electrode pairs 21. An electrode plate, or two pairs of electrode plates connected to a second interdigitated electrode pair 22 . Several microcavities 30 are arranged in a horizontal and vertical array. A pair of interdigitated electrodes can be seen in a microcavity 30, so that when the electrodes are energized, it is convenient to clearly observe the movement direction of the microspheres. For the convenience of observation, the section of the microcavity 30 is circular, the diameter is preferably set at 15-25 microns, and the depth is 8-15 microns. In this embodiment, the diameter is set at 20 microns and the depth is 10 microns.

In order to facilitate fast connection and energization of each interdigital electrode of the dielectrophoretic test chip, the first interdigital electrode pair 21 includes a first pole plate 211 and a second pole plate 212, and the first interdigital electrode pair 21 of each first interdigital electrode pair 21 The pole plates 211 are connected to each other. In this embodiment, as shown in the figure, the first pole plates 211 of each first interdigitated electrode pair 21 are connected through a conductive copper strip 213 connected to the top.

In order to quickly connect and conduct the same type of electrode plates at the same time, the negative adhesive layer 3 is provided with a first conductive strip 31 , a second conductive strip 32 and a third conductive strip 33 . The first conductive strip 31 is connected to the second electrode plate 212 of each first interdigital electrode pair 21 . The second interdigitated electrode pair 22 includes a third pole plate 221 and a fourth pole plate 222, the second conductive strip 32 is connected to the third pole plate 221 of each second interdigitated electrode pair 22, and the third conductive strip 33 is connected to each second pole plate 221. The fourth plate 222 of the pair of interdigitated electrodes 22 is connected. In this embodiment, the negative adhesive layer 3 is an insulating layer, and the first conductive strip 31, the second conductive strip 32, and the third conductive strip 33 are arranged outside the negative adhesive layer 3, only when each conductive strip needs to be connected to a corresponding plate , by setting a hollow at the position of the negative adhesive layer 3 corresponding to the pole plate, each conductive strip can be connected to the corresponding pole plate, so that all the corresponding pole plates of the same type can be connected only by electrically connecting each conductive strip. When the second pole plate 212 of each first interdigitated electrode pair 21 is energized, because all the second pole plates 212 are connected to the first conductive strip 31, so the first conductive strip 31 is directly conductive, that is, all the second pole plates 212 are connected to the first conductive strip 31. The diode plate 212 conducts electricity. In this embodiment, each conductive strip is a copper conductive layer.

A positioning block 5 is provided on the negative adhesive layer 3 , and a positioning block 5 is provided at the front and rear of any interdigitated electrode group. Through the setting of the positioning block 5, when observing the movement of the microsphere, there is a positioning reference plane, so that the test is faster and more accurate.

Preparation The dielectrophoretic force test chip in this embodiment can be manufactured using the existing technology, and the first layer of glass substrate is cleaned. The preparation of the second layer, that is, the electrode layer 2, adopts a combination of photolithography and wet etching. For the negative adhesive layer, the SU-8 negative adhesive is prepared by photolithography. For the conductive strips, that is, the third layer, a copper conductive layer is prepared by magnetron sputtering to form the conductive regions of the first pair of interdigitated electrodes 21 and the second pair of interdigitated electrodes 22 . For the fourth layer, that is, the positioning block 5, a SU-8 negative resist is prepared by photolithography, and the height is 10 microns. Because the manufacture of the chip belongs to the conventional technology, for example, the CN114921341A patent document has more detailed records, and this patent will not repeat them.

As shown in FIG. 1 to FIG. 3 , the present invention also provides a DEP test device, including the above-mentioned DEP test chip. Also includes a clamp 6, the clamp 6 includes a glass slide base plate 61, the slide glass base plate 61 is provided with a front clamping wall 62 and a rear clamping wall 63, the front clamping wall 62 and the rear clamping wall 63 can be made by 3D printing, the front clamping wall The wall 62 and the rear clamping wall 63 form a cavity 64 with a gap at the contact point. In this embodiment, the cavity 64 has a square cross section. The dielectrophoretic force test chip is packaged and inserted into the gap. In this embodiment, it is packaged with ecoflex silica gel, which will not leak during the test. In order to further ensure the tightness of the gap, it can be sealed by dripping glue. The cavity 64 can hold the microsphere solution to realize the following DEP test method.

The present invention also provides a method for testing dielectrophoretic force, using the above dielectrophoretic force chip dielectrophoretic test device, comprising the following steps:

S1: Stand the dielectrophoretic force test chip in a cavity 64, the bottom of the cavity 64 is a glass slide base plate 61, in this embodiment, insert the dielectrophoretic force test core into the front clamping wall 62 and the rear clamping wall 63 to enclose In the formed cavity 64 , the pole plates of the first interdigital electrode pair 21 and the second interdigital electrode pair stand vertically in the cavity 64 .

S2: add microsphere solution in cavity 64;

S3: Use two beams of optical traps to trap microspheres above the first pair of interdigitated electrodes 21 and the second pair of interdigitated electrodes 22, each beam of optical traps captures at least one microsphere, and the height of the captured microspheres is on the same plane. The same plane can be marked with the positioning block 5, for example, the height of the microsphere and the lowermost surface of the positioning block 5 can be on the same plane, that is, the same focal plane is observed under a 60 times oil lens.

S4: Apply a sinusoidal electrical signal to the first interdigitated electrode pair 21, and the microspheres are subjected to dielectrophoretic force to move laterally in the optical trap;

S5: Observe the moving direction of the microspheres, determine the direction of the dielectrophoretic force, and analyze the dielectrophoretic force and the mutual inductance electric field on the microspheres that are subjected to the applied electricity by testing and calculating the transverse optical trap force received by the two microspheres. The difference in the size of the dielectrophoretic force. Specifically, the moving distance of the microsphere can be detected by the four-quadrant detector, and then the dielectrophoretic force on the microsphere can be calculated by Hooke's law.

The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and changes according to the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims (10)

1. A dielectrophoretic force test chip, characterized in that: comprising a base layer (1), the base layer (1) is provided with an electrode layer (2), and the electrode layer (2) includes at least one first fork A finger electrode pair (21) and at least one second interdigital electrode pair (22), the pole plates of the first interdigital electrode pair (21) and the second interdigital electrode pair (22) are vertically arranged. 2. The dielectrophoretic force test chip as claimed in claim 1, characterized in that: said first interdigital electrode pair (21) and the second interdigital electrode pair (22) are arranged in pairs, and a first interdigital electrode The pair (21) and a second interdigitated electrode pair (22) form an interdigitated electrode group. 3. dielectrophoretic force test chip as claimed in claim 2, is characterized in that: described electrode layer (2) top is negative adhesive layer (3), and described negative adhesive layer (3) is provided with some microcavities ( 30), the single microcavity (30) communicates with any first interdigitated electrode pair (21) of two paired pole plates, or communicates with any second interdigitated electrode pair (22) of two paired poles plate. 4. The dielectrophoretic test chip according to claim 3, characterized in that: several microcavities (30) are arranged in a horizontal and vertical array. 5. The dielectrophoretic test chip according to claim 3, characterized in that: the microcavity (30) has a circular cross-section, a diameter of 15-25 microns, and a depth of 8-15 microns. 6. The dielectrophoretic force test chip as claimed in claim 3, characterized in that: said first interdigitated electrode pair (21) comprises a first pole plate (211) and a second pole plate (212), each of said The first pole plates (211) of the first interdigitated electrode pair (21) are connected to each other; The negative adhesive layer (3) is provided with a first conductive strip (31), and the first conductive strip (31) is connected to the second pole plate (212) of each of the first interdigitated electrode pairs (21) ; The second interdigitated electrode pair (22) includes a third pole plate (221) and a fourth pole plate (222); The negative adhesive layer (3) is provided with a second conductive strip (32), and the second conductive strip (32) is connected to the third plate (221) of each second interdigitated electrode pair (22) ; A third conductive strip (33) is also arranged on the negative adhesive layer (3), and the third conductive strip (33) is connected to the fourth electrode plate (222) of each second interdigitated electrode pair (22). connect. 7. The dielectrophoretic force test chip as claimed in claim 3, characterized in that: said negative glue layer (3) layer is provided with a positioning block (5), and any said interdigitated electrode group is provided with a positioning block before and after. block (5). 8. A dielectrophoretic test device, characterized in that it comprises the dielectrophoretic test chip according to any one of claims 1 to 7. 9. dielectrophoretic force testing device as claimed in claim 8, is characterized in that: also comprise fixture (6), and described fixture (6) comprises glass slide bottom plate (61), and described glass slide bottom plate (61) A front clamping wall (62) and a rear clamping wall (63) are arranged on the top, and the front clamping wall (62) and the rear clamping wall (63) enclose a cavity (64) with a gap at the contact point, and the dielectrophoretic force The test chip is inserted into the gap after being packaged. 10. A dielectrophoretic force testing method, using the dielectrophoretic force chip according to any one of claims 1 to 7 or the dielectrophoretic force testing device according to claim 8 or 9, characterized in that it comprises the following steps: S1: Standing the dielectrophoretic force chip in a cavity (64), the bottom of the cavity (64) is a glass slide bottom plate (61); S2: adding the microsphere solution into the cavity (64); S3: Use two beams of light traps to trap microspheres above the first pair of interdigitated electrodes (21) and the second pair of interdigitated electrodes (22), each beam of light traps captures at least one microsphere; the height of the captured microspheres is on the same plane ; S4: Apply a sinusoidal electrical signal to the first interdigitated electrode pair (21), and the microspheres are subjected to dielectrophoretic force to move laterally in the optical trap; S5: Observe the moving direction of the microspheres, determine the direction of the dielectrophoretic force, and analyze the dielectrophoretic force and the mutual inductance electric field on the microspheres that are subjected to the applied electricity by testing and calculating the transverse optical trap force received by the two microspheres. The difference in the size of the dielectrophoretic force.

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