CN117483018A - Biological particle separation device, processing method and microfluidic chip - Google Patents

Abstract

The invention discloses a biological particle separating device, a processing method and a micro-fluidic chip, wherein the biological particle separating device comprises: a microchannel comprising a particle suspension inlet, a focusing sheath liquid inlet, a sample channel, a particle suspension outlet, a focusing sheath liquid outlet, the particle suspension inlet and the focusing sheath liquid inlet communicating the particle suspension outlet and the focusing sheath liquid outlet via the sample channel; the liquid metal inlet is communicated with the liquid metal outlet through the electrode runner, and the electrode runner is used for forming at least one group of three-dimensional microelectrodes with opposite polarities; and the substrate is used for fixing the micro-flow channel, the liquid metal inlet, the electrode flow channel and the liquid metal outlet. The biological particle separation device disclosed by the embodiment of the disclosure realizes continuous, progressive and high-flux dielectrophoresis biological particle separation.

Description

Biological particle separation device, processing method and microfluidic chip

Technical Field

The present invention relates to the field of microfluidic technology, and in particular to a biological particle separation device, a processing method and a microfluidic chip.

Background Art

Complex fluid samples contain microparticles, cells, droplets and other contaminants. How to separate these biological particles has become a key issue in many application fields, such as industrial applications, environmental assessment, biochemical analysis and so on.

In the related art, the method based on biomarkers is the main tool for bioparticle separation, which identifies specific bioparticle populations by marking bioparticles (such as cells) with molecular-specific labels (such as fluorescent dyes, quantum dots, magnetic beads, and stable isotopes, etc.). Labeling bioparticles not only requires prior knowledge of the specificity of bioparticles, but is also limited by expensive equipment, long time consumption, and the potential impact of labeling on downstream analysis.

In addition, related technologies also use label-free methods to separate bioparticles. In contrast, label-free methods achieve separation of bioparticles by identifying and utilizing the intrinsic characteristics of bioparticles, such as size, density, biophysical properties, etc., avoiding the use of external markers, making it easier to maintain the integrity and biological activity of bioparticles, and can achieve non-invasive, high-throughput and efficient separation of bioparticles. This makes it a potential bioparticle separation and research tool and has attracted widespread attention. Label-free bioparticle separation methods, such as density gradient centrifugation, gravity sedimentation, and filtration membrane separation. These methods are often used to separate target bioparticles from heterogeneous biofluid samples. Most of them perform well in terms of processing throughput, helping researchers to make great progress in their understanding and knowledge of bioparticles. However, these methods have problems with low purity, recovery rate and biological activity, which limits their applicability for further analysis and evaluation.

Compared with the above methods, dielectrophoresis microfluidics can separate biological particles based on their size and dielectric properties, providing accurate, fast, low-cost and label-free biological particle manipulation capabilities. However, due to the limited range of dielectrophoretic force, the bioparticle separation method based on dielectrophoresis microfluidics cannot provide sufficient dielectrophoretic force action time when processing samples with high flow rates, and the processing throughput will be relatively low.

Summary of the invention

In view of this, the present disclosure proposes a technical solution for separating biological particles.

In one possible implementation, the device includes: a microfluidic channel, the microfluidic channel including a particle suspension inlet, a focusing sheath liquid inlet, a sample channel, a particle suspension outlet, and a focusing sheath liquid outlet, the particle suspension inlet and the focusing sheath liquid inlet are connected to the particle suspension outlet and the focusing sheath liquid outlet via the sample channel; a liquid metal inlet, an electrode channel, and a liquid metal outlet, the liquid metal inlet is connected to the liquid metal outlet via the electrode channel, and the electrode channel is used to form at least one set of three-dimensional microelectrodes with opposite polarities; and a substrate, used to fix the microfluidic channel, the liquid metal inlet, the electrode channel, and the liquid metal outlet.

In a possible implementation, the electrode flow channel includes a capillary valve with different trigger pressure thresholds, and the capillary valve is used to control the flow direction of the liquid metal in the electrode flow channel.

In a possible implementation, the capillary valve includes a stop valve and a passive switching valve, the electrode flow channel is connected to the sample flow channel through the stop valve, the first path of the electrode flow channel is connected to the second path of the branch through the passive switching valve, the cross-sectional area of the electrode flow channel is larger than the cross-sectional area of the passive switching valve, and the cross-sectional area of the passive switching valve is larger than the cross-sectional area of the stop valve.

In one possible implementation, the shut-off valve is used to prevent the liquid metal from entering the sample flow channel after filling the first path of the electrode flow channel; the passive switching valve is used to: prevent the liquid metal from entering the branched second path when the liquid metal does not fill the first path of the electrode flow channel, and switch the flow direction of the liquid metal from the first path to the branched second path when the liquid metal fills the first path of the electrode flow channel.

In a possible implementation, the electrode flow channel adopts an asymmetric electrode setting, and each stop valve set on the positive electrode side corresponds to multiple stop valves set on the negative electrode side, or each stop valve set on the negative electrode side corresponds to multiple stop valves set on the positive electrode side.

In a possible implementation, the particle suspension inlet and the particle suspension outlet are connected to a microfluidic pump via a plastic hose, so that the flow of the particle suspension in the microfluidic channel is controlled by the microfluidic pump.

In a possible implementation, the liquid metal includes at least one of indium, tin, cadmium, bismuth, lead, and gallium.

According to another aspect of the present disclosure, a method for processing a biological particle separation device is provided, the method comprising: manufacturing the biological particle separation device as described above by a soft lithography process; injecting liquid metal into a liquid metal inlet of the biological particle separation device, and utilizing a capillary valve with different trigger pressure thresholds to integrate a large array of three-dimensional microelectrodes into the electrode pattern of the self-assembled biological particle separation device.

In a possible implementation, the capillary valve includes a stop valve and a passive switching valve, the electrode flow channel is connected to the sample flow channel through the stop valve, the first path of the electrode flow channel is connected to the second path of the branch through the passive switching valve, the cross-sectional area of the electrode flow channel is larger than the cross-sectional area of the passive switching valve, and the cross-sectional area of the passive switching valve is larger than the cross-sectional area of the stop valve; the self-assembly process of the bioparticle separation device includes: when liquid metal is injected into the electrode flow channel and flows to the path branch, the passive switching valve prevents the liquid metal from entering the second path of the branch, and the liquid metal flows forward along the first path; when the liquid metal fills the first path of the electrode flow channel, the stop valve prevents the liquid metal from entering the sample flow channel, and the passive switching valve switches the flow direction of the liquid metal from the first path to the second path of the branch; when the liquid metal enters the second path of the branch, the second path of the branch is used as the first path of the trunk, and the above process is repeated until the flowing liquid metal fills the electrode flow channel to form an electrode pattern.

According to another aspect of the present disclosure, a microfluidic chip is provided, comprising the biological particle separation device as described above.

In the disclosed embodiment, the biological particle separation device includes: a microfluidic channel, the microfluidic channel includes a particle suspension inlet, a focusing sheath liquid inlet, a sample flow channel, a particle suspension outlet, and a focusing sheath liquid outlet, wherein the particle suspension inlet and the focusing sheath liquid inlet are connected to the particle suspension outlet and the focusing sheath liquid outlet via the sample flow channel; a liquid metal inlet, an electrode flow channel, and a liquid metal outlet, wherein the liquid metal inlet is connected to the liquid metal outlet via the electrode flow channel, and the electrode flow channel is used to form at least one set of three-dimensional microelectrodes with opposite polarities; and a substrate for fixing the microfluidic channel, the liquid metal inlet, the electrode flow channel, and the liquid metal outlet. In this way, a large array of three-dimensional microelectrodes based on liquid metal can be integrated in a compact microfluidic channel, and a large number of series-connected electric field gradients can be generated in the microfluidic channel to provide a larger range of action and a longer action time of dielectrophoretic force for biological particle manipulation, thereby achieving continuous, progressive, and high-throughput biological particle separation.

It should be understood that the above general description and the following detailed description are exemplary and explanatory only and do not limit the present disclosure. Other features and aspects of the present disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and are used to illustrate the technical solutions of the present disclosure together with the specification.

FIG1 is a schematic structural diagram of a biological particle separation device according to an embodiment of the present disclosure.

FIG2 is a schematic diagram showing a biological particle separation device according to an embodiment of the present disclosure that integrates a large array of three-dimensional microelectrodes.

FIG. 3 is a schematic diagram showing the capillary valve principle according to an embodiment of the present disclosure.

FIG. 4 is a schematic diagram showing the structure of the electrode flow channel according to an embodiment of the present disclosure.

FIG5 is a schematic diagram showing a liquid metal electrode array self-assembly workflow according to an embodiment of the present disclosure.

FIG. 6 shows a schematic diagram of a uniform sphere model and a single-shell sphere model according to an embodiment of the present disclosure.

FIG. 7 is a schematic diagram showing a simulation of the electric field strength of a three-dimensional microelectrode according to an embodiment of the present disclosure.

FIG. 8 is a schematic diagram showing a verification experiment of the biological particle separation device according to an embodiment of the present disclosure.

FIG. 9 is a schematic diagram showing another verification experiment of the biological particle separation device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

The term "and/or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present disclosure.

Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

Microfluidics can use microchannels (tens to hundreds of microns in size) to process or manipulate tiny fluids (nanoliter to attoliter in volume). Microfluidics requires small sample volume, has strong integration capabilities, good biocompatibility, and fast response speed, and has strong advantages in system integration. Among them, the microfluidic method based on dielectrophoresis, as an electrodynamic method, can perform label-free, controllable, low-damage, and low-cost separation of biological particles based on particle size and dielectric properties. Dielectrophoresis microfluidic devices are widely used in the manipulation of biological particles such as cancer cells, blood cells, bacteria, and proteins. Although dielectrophoresis technology is widely used in biotechnology, low throughput remains a key obstacle to its commercial application.

In order to improve the sample processing throughput of the dielectrophoresis microfluidic device, in the related art, three-dimensional electrodes can be used to replace planar electrodes in the device. For example, a microfluidic device using a conductive ionic liquid as a three-dimensional electrode on the side wall can use the surface tension of the liquid to maintain the position of the conductive ionic liquid and apply a dielectrophoretic force to the biological particles traveling in the sample channel. For another example, a microfluidic device using a conductive polymer formed by a mixture of silver and polydimethylsiloxane as a three-dimensional staggered electrode can use the dielectrophoretic force generated by the staggered electrode tracks to induce the separation of biological particles. These methods are easy to manufacture three-dimensional electrodes in microfluidic devices, but the electrode materials used have low conductivity, which affects the electric field coupling and limits their applicability to high-throughput separation scenarios.

Liquid metal alloys combine excellent electrical conductivity with good fluidity, making them the target material for constructing three-dimensional electrodes in high-throughput microfluidic devices. Injecting liquid metal alloys into microchannels can make simple three-dimensional contact electrodes aligned with the flow channels and generate strong and uniform three-dimensional electric fields in the microchannels. For example, in the related art, micro-column obstacles can be set in the microchannel to separate the electrode flow channel from the sample flow channel to prevent liquid metal from flowing into the sample flow channel. The liquid metal is then injected into the designed electrode flow channel as a liquid at a certain temperature. When it returns to room temperature and the liquid metal alloy solidifies, a self-assembled three-dimensional electrode array is formed between the micro-columns on both sides of the sample flow channel. Such a method of co-manufacturing liquid metal electrodes and sample channels lacks the ability to accurately control the flow of liquid metal, usually only contains the simplest patterns such as straight lines and curves, and has low space utilization. When faced with high-throughput scenarios that require increasing the number of electrodes as much as possible, it will inevitably lead to an unrealistic expansion of the chip size and cannot be achieved.

Therefore, in the sample separation task, microfluidic devices using ionic liquids and conductive polymers as electrode materials cannot exert sufficient dielectrophoretic force on samples at high flow rates due to the low conductivity of the electrode materials, which affects the electric field flow field coupling efficiency, limiting the improvement of flux. Devices using liquid metal alloys as electrode materials cannot construct electrodes with complex patterns due to the lack of methods to accurately control the flow of liquid metal. Therefore, it is difficult to integrate a large array of three-dimensional liquid metal electrodes in a microfluidic chip with limited size. The limited number of electrodes cannot provide sufficient dielectrophoretic force action time for high-flow rate samples, making it difficult to improve sample processing throughput.

In order to improve the ability of label-free separation of particles in high-throughput scenarios, an embodiment of the present disclosure provides a biological particle separation device that can integrate a large array of liquid metal-based three-dimensional microelectrodes in a compact microfluidic channel. By generating a large number of series-connected electric field gradients in the microfluidic channel, a dielectrophoretic force with a larger range and longer action time is provided for biological particle manipulation, thereby achieving continuous, progressive and high-throughput biological particle separation.

Figure 1 shows a schematic structural diagram of a biological particle separation device according to an embodiment of the present disclosure. As shown in Figure 1 , the biological particle separation device includes a microfluidic channel (see the blue part in Figure 1 ), and the microfluidic channel includes a particle suspension inlet 101, a focusing sheath fluid inlet 102, a sample flow channel 103, a particle suspension outlet 104, and a focusing sheath fluid outlet 105. The particle suspension inlet 101 and the focusing sheath fluid inlet 102 are connected to the particle suspension outlet 104 and the focusing sheath fluid outlet 105 via the sample flow channel 103.

The bioparticle separation device also includes a liquid metal inlet, an electrode flow channel, and a liquid metal outlet (see the yellow part in FIG1 ), and the liquid metal inlet is connected to the liquid metal outlet via the electrode flow channel. As shown in FIG1 , the liquid metal inlet 201 is connected to the liquid metal outlet 202 via the electrode flow channel 206; the liquid metal inlet 203 is connected to the liquid metal outlet 204 via the electrode flow channel 205. Among them, the polarity of the liquid metal inlet 201, the electrode flow channel 206, and the liquid metal outlet 202 is the same, and the polarity of the liquid metal inlet 201, the electrode flow channel 206, and the liquid metal outlet 204 is the same, and the polarity of the liquid metal inlet 201, the electrode flow channel 206, and the liquid metal outlet 202 is relative (or opposite) to the polarity of the liquid metal inlet 203, the electrode flow channel 205, and the liquid metal outlet 204. The electrode flow channel 205 and the electrode flow channel 206 can be used to form at least one group of three-dimensional microelectrodes with opposite polarities, and the number of the three-dimensional microelectrodes formed is positively correlated with the length of the electrode flow channel.

The bioparticle separation device further includes a substrate 301 for fixing the microchannel, the liquid metal inlet, the electrode channel, and the liquid metal outlet.

In a possible implementation, due to the conductivity of metal, the polarity of the electrode flow channel can be set by applying electrical signals of different polarities to the electrode flow channel. In order to make the polarities of the two electrode flow channels 205 and the electrode flow channel 206 on both sides of the sample flow channel 103 different, the polarity of the liquid metal inlet 201, the electrode flow channel 206, and the liquid metal outlet 202 can be set to the positive pole, and the polarity of the liquid metal inlet 203, the electrode flow channel 205, and the liquid metal outlet 204 can be set to the negative pole; the polarity of the liquid metal inlet 201, the electrode flow channel 206, and the liquid metal outlet 202 can also be set to the negative pole, and the polarity of the liquid metal inlet 203, the electrode flow channel 205, and the liquid metal outlet 204 can be set to the positive pole, and the present disclosure does not limit this.

In one possible implementation, electrode channels with opposite polarities are embedded in a microchannel. When two electrode channels 205 and 206 with opposite polarities are provided on both sides of a sample channel 103 of the microchannel, the shapes of the sample channel 103, the electrode channel 205 and the electrode channel 206 can be set to various shapes such as circular, trapezoidal, rectangular or square. The shapes and sizes of the sample channel 103, the electrode channel 205 and the electrode channel 206 can be matched and designed according to the size of the particles to be tested, and the present disclosure does not impose any restrictions on this.

In the example shown in FIG1 , the portion of the sample channel 103 between the particle suspension inlet 101, the focusing sheath liquid inlet 102, the particle suspension outlet 104, and the focusing sheath liquid outlet 105 is arranged in a "Z" shape, with an unlimited number of turns. Accordingly, the electrode channel 205 and the electrode channel 206 may be in a "comb" shape, and each have an extension portion in the shape of a "comb tooth" (for example, the first extension portion 205-1, the second extension portion 205-2, and the third extension portion 205-3 corresponding to the electrode channel 205; the first extension portion 206-1, the second extension portion 206-2, and the third extension portion 206-3 corresponding to the electrode channel 206), extending to the gap in the sample channel 103, forming a structure similar to a "finger insertion", and there are always electrode channels 205 and electrode channels 206 with opposite polarities on both sides of the sample channel 103, that is, one side is the electrode channel 205 and the other side is the electrode channel 206. In the example shown in FIG1 , the liquid metal inlet 203 and the liquid metal outlet 204 are located on the first side of the substrate 301, the liquid metal inlet 201 and the liquid metal outlet 202 are located on the second side opposite to the first side, the particle suspension outlet 104 and the focusing sheath liquid outlet 105 are located on the third side adjacent to the first side and close to the liquid metal inlet 203 and the liquid metal outlet 204, and the particle suspension inlet 101 and the focusing sheath liquid inlet 102 are located on the fourth side opposite to the third side and close to the liquid metal inlet 201 and the liquid metal outlet 202. Those skilled in the art should understand that the specific positions and shapes of the above components can be changed as needed, and the present application does not limit this.

Similarly, the embodiments of the present disclosure do not impose specific restrictions on the shapes and sizes of the particle suspension inlet 101, the focusing sheath liquid inlet 102, the particle suspension outlet 104, the focusing sheath liquid outlet 105, the liquid metal inlets 201 and the liquid metal inlets 203 with opposite polarities, and the liquid metal outlets 202 and the liquid metal outlets 204 with opposite polarities, and these inlets and outlets can be flexibly configured according to actual usage scenarios.

Among them, the number of three-dimensional microelectrodes formed is related to the length of the electrode flow channel. The longer the length of the electrode flow channel is, the more three-dimensional microelectrodes can be formed. In practical applications, the number of three-dimensional microelectrodes can be increased infinitely. According to the number of three-dimensional microelectrodes, the length of the sample flow channel 103 can be increased accordingly.

In a possible implementation, the liquid metal includes at least one of indium, tin, cadmium, bismuth, lead, and gallium. The electrode flow channel may be filled with a liquid metal element or a liquid metal alloy, for example, a liquid metal composed of an alloy of indium, tin, cadmium, bismuth, and lead, a liquid metal composed of a gallium element, and a liquid metal composed of a gallium-indium alloy. The present disclosure does not limit the specific constituent material of the liquid metal.

In a possible implementation, an embodiment of the present disclosure further provides a microfluidic chip, including the biological particle separation device shown in FIG. 1 .

Figure 2 shows a schematic diagram of a biological particle separation device according to an embodiment of the present disclosure that integrates a large array of three-dimensional microelectrodes. As shown in Figure 2, part b shows a microfluidic chip as an example of a biological particle separation device. The microfluidic chip adopts the structure shown in Figure 1. After power-on, it is equivalent to integrating a large number (for example, 5,000 pairs) of three-dimensional liquid metal electrodes in the chip. The equivalent structure of each pair of three-dimensional microelectrodes is as shown in part 401 of the figure, and the equivalent connection between each pair of three-dimensional microelectrodes is shown in part c.

It should be understood that the spacing between any two adjacent pairs of three-dimensional microelectrodes 401 can be set to any value. For example, as shown in Figure 2, along the sample flow channel 103, for the spacing L1 between the first pair of three-dimensional microelectrodes 401 and the second pair of three-dimensional microelectrodes 401, the spacing L2 between the second pair of three-dimensional microelectrodes 401 and the third pair of three-dimensional microelectrodes 401, and the spacing L3 between the second pair of three-dimensional microelectrodes 401 and the third pair of three-dimensional microelectrodes 401, L1, L2, and L3 can be set to the same value, or L1, L2, and L3 can be set to different values. The embodiments of the present disclosure do not limit the spacing between the three-dimensional microelectrodes 401.

In a possible implementation, the sample flow channel 103 and the electrode flow channel (eg, the electrode flow channel 205 and the electrode flow channel 206 with opposite polarities) are manufactured by a soft photolithography process and are formed by polydimethylsiloxane (PDMS) molding.

Optionally, the liquid metal can be injected into the electrode flow channel by driving a syringe by hand pushing or other mechanical means (such as using a microfluidic pump, a linear motor, etc.), thereby forming a self-assembled pattern.

Optionally, the particle suspension inlet 101 and the particle suspension outlet 104 are connected to a microfluidic pump via a plastic hose to control the flow of the particle suspension in the microchannel via the microfluidic pump. Sampling can also be achieved by suctioning a syringe at the particle suspension outlet 104 .

Optionally, the focusing sheath liquid inlet 102 and the focusing sheath liquid outlet 105 may also be connected to a microfluidic pump via a plastic hose so that the flow of the focusing sheath liquid in the microchannel is controlled by the microfluidic pump, and sampling may also be achieved by suctioning a syringe at the focusing sheath liquid outlet 105.

Optionally, the microchannel composed of the particle suspension inlet 101, the focusing sheath liquid inlet 102, the sample flow channel 103, the particle suspension outlet 104, and the focusing sheath liquid outlet 105, and the three-dimensional microelectrode array formed by the liquid metal inlet 201 and the liquid metal inlet 203 with opposite polarities, the electrode flow channels 205 and the electrode flow channels 206 with opposite polarities, and the liquid metal outlet 202 and the liquid metal outlet 204 with opposite polarities can be fixed in an irreversible manner or bonded in a reversible manner, so that the biological particle separation device can be disassembled after processing a batch of samples, and after necessary elution, disinfection and other treatments, it can be re-bonded with a new substrate for the next batch of samples.

Optionally, to facilitate the application of electrical signals, the electrode channels can be connected together by wires with a custom printed circuit board that matches the electrode pattern. In an example, a signal generator can be connected to the electrode channels filled with liquid metal via a power amplifier to provide an electrical signal to the bioparticle separation device. The applied electrical signal can also be observed using an oscilloscope.

The bioparticle separation device of the disclosed embodiment integrates a large array of three-dimensional liquid metal alloy microelectrodes on a chip, which is conducive to constructing high-throughput dielectrophoresis microfluidic devices and systems to achieve continuous, progressive and high-throughput dielectrophoresis bioparticle separation.

The working principle and structural design of the biological particle separation device of the embodiment of the present disclosure are exemplarily described below.

In a possible implementation, the electrode flow channel includes a capillary valve with different trigger pressure thresholds, and the capillary valve is used to control the flow direction of the liquid metal in the electrode flow channel.

The electrode flow channel (e.g., electrode flow channel 205 and electrode flow channel 206 of opposite polarity) has a Laplace pressure on the input liquid metal therein, and this obstruction pressure needs to be overcome before the input liquid metal starts to flow through the electrode flow channel. For example, if the surface of the input liquid metal in the electrode flow channel becomes higher, the bending of the surface of the input liquid metal during its rise in the microfluidic tube will form a pressure difference, forming a Laplace pressure that hinders the flow of the input liquid metal.

Among them, different geometric shapes of the microfluidic channel will lead to different bending conditions of the input liquid metal surface, and the Laplace pressure can be determined by the geometric shape of the microfluidic channel.

FIG3 is a schematic diagram of the capillary valve principle of an embodiment of the present disclosure. As shown in FIG3 , if the shape of the electrode flow channel is a straight flow channel as shown in part a of FIG3 , and its cross-sectional shape perpendicular to the flow direction of the liquid metal is a rectangle, the Laplace pressure of the electrode flow channel can be calculated by the following formula:

In formula (1), ΔP _str is the Laplace pressure of the electrode flow channel in the shape of a straight channel, γ is the surface tension between the liquid metal and the gas. For a solid-like film formed by oxidation of the liquid metal and gas interface, γ depends on the mechanical properties of the film, θ _c is the contact angle of the advancing liquid metal, w represents the width of the cross-sectional shape of the electrode flow channel perpendicular to the flow direction of the liquid metal, and h represents the height of the cross-sectional shape of the electrode flow channel perpendicular to the flow direction of the liquid metal.

The sudden expansion of the width or height of the electrode flow channel will lead to the emergence of additional Laplace pressure. As shown in part b of Figure 3, the Laplace pressure of the electrode flow channel with the expansion structure is as follows:

In formula (2), ΔP _exp is the Laplace pressure of the electrode flow channel with an expansion structure, γ is the surface tension between the liquid metal and the gas. For a solid-like film formed by oxidation of the interface between the liquid metal and the gas, γ depends on the mechanical properties of the film, θ _c is the contact angle of the advancing liquid metal, β is the cone angle at the expansion structure, w represents the width of the cross-sectional shape of the electrode flow channel perpendicular to the flow direction of the liquid metal, and h represents the height of the cross-sectional shape of the electrode flow channel perpendicular to the flow direction of the liquid metal.

According to the description of formula (1) and formula (2), for electrode flow channels with the same width w and height h, ΔP _exp is greater than ΔP _str . When the liquid metal reaches the intersection of the direct flow channel and the expansion flow channel with the same width w and height h, the liquid metal will first flow into the direct flow channel because the capillary valve corresponding to the direct flow channel has a lower Laplace pressure. Therefore, by placing capillary valves with different trigger pressure thresholds at appropriate positions in the electrode flow channel, the flow direction of the liquid metal in the electrode flow channel can be controlled, which is conducive to maximizing the integration of three-dimensional liquid metal electrodes in the limited chip space of the bioparticle separation device of the embodiment of the present disclosure, thereby realizing high-throughput progressive dielectrophoresis sample processing.

In one possible implementation, the principle of controlling the flow of liquid metal by expanding the Laplace pressure in the electrode flow channel through a sudden change in the pipe size to act as a capillary valve can be achieved by changing the cross-sectional area of the electrode flow channel (for example, changing the width or height of the electrode flow channel).

In order to increase the spatial density of the liquid metal electrodes in the bioparticle separation device of the disclosed embodiment, the liquid metal can be given the ability to switch flow paths during the process of filling the electrode flow channel, thereby self-assembling into a compact electrode pattern.

In one possible implementation, in order to reliably and efficiently achieve the goal of liquid metal self-assembly into a compact electrode pattern, the electrode flow channel may include capillary valves with different trigger pressure thresholds, and the capillary valves may be used to provide robust passive liquid control capabilities. FIG4 shows a schematic structural diagram of the electrode flow channel of an embodiment of the present disclosure. As shown in FIG4, the capillary valve of the electrode flow channel may include a shut-off valve and a passive switching valve. The electrode flow channel is connected to the sample flow channel through the shut-off valve, and the first path of the electrode flow channel is connected to the second path of the branch through the passive switching valve. The cross-sectional area S1 of the electrode flow channel is greater than the cross-sectional area S2 of the passive switching valve, and the cross-sectional area S2 of the passive switching valve is greater than the cross-sectional area S3 of the shut-off valve.

The first path refers to the main path of the current liquid metal flow, and the second path refers to the branch path. Taking Figure 1 as an example, the electrode flow channel 205 includes a first part 205-1, a second part 205-2 and a third part 205-3. When the liquid metal enters the electrode flow channel 205 from the liquid metal inlet 203, 205-1 is the first path, 205-2 is the second path, and a passive switching valve is set at the intersection of 205-1 and 205-2, so that the liquid metal fills 205-1 and then continues to fill 205-2. At this time, 205-2 is the first path and 205-3 is the second path. A passive switching valve is also set at the intersection of 205-2 and 205-3, so that the liquid metal fills 205-2 and then continues to fill 205-3, and finally reaches the liquid metal outlet 204. Still taking FIG. 1 as an example, a plurality of stop valves may be arranged at specified intervals along the electrode flow channel 205 . The embodiments of the present disclosure do not limit the specific intervals, and the intervals may be set according to specific application scenarios.

The electrode flow channel 206 is similar to the electrode flow channel 206. Taking Figure 1 as an example, the electrode flow channel 206 includes a first part 206-1, a second part 206-2 and a third part 206-3. When liquid metal enters the electrode flow channel 206 from the liquid metal inlet 201, 206-1 is the first path and 206-2 is the second path. A passive switching valve is set at the intersection of 206-1 and 206-2, so that after the liquid metal fills 206-1, 206-2 continues to be filled. At this time, 206-2 is the first path and 206-3 is the second path. A passive switching valve is also set at the intersection of 206-2 and 206-3, so that after the liquid metal fills 206-2, 206-3 continues to be filled, and finally reaches the liquid metal outlet 204. Still taking FIG. 1 as an example, a plurality of stop valves may be arranged at specified intervals along the electrode flow channel 206 . The embodiments of the present disclosure do not limit the specific intervals, and the intervals may be set according to specific application scenarios.

Among them, the cross-sectional area S1 of the electrode flow channel represents the area of the cross section in the electrode flow channel perpendicular to the flow direction of the liquid metal, the cross-sectional area S2 of the passive switching valve represents the area of the cross section in the passive switching valve perpendicular to the flow direction of the liquid metal, and the cross-sectional area S3 of the stop valve represents the area of the cross section in the stop valve perpendicular to the flow direction of the liquid metal.

Combining formulas (1) and (2), it can be seen that the size of the cross section is negatively correlated with the trigger pressure threshold that hinders the flow of liquid metal. The larger the cross section area, the smaller the corresponding trigger pressure threshold; the smaller the cross section area, the larger the corresponding trigger pressure threshold. Since the cross-sectional area S1 of the electrode flow channel> the cross-sectional area S2 of the passive switching valve> the cross-sectional area S3 of the stop valve, the trigger pressure threshold of the electrode flow channel < the trigger pressure threshold of the passive switching valve < the trigger pressure threshold of the stop valve.

With this arrangement, the shut-off valve is used to prevent the liquid metal from entering the sample flow channel after filling the first path of the electrode flow channel; the passive switching valve is used to: prevent the liquid metal from entering the branched second path when the liquid metal does not fill the first path of the electrode flow channel, and switch the flow direction of the liquid metal from the first path to the branched second path when the liquid metal fills the first path of the electrode flow channel.

As shown in FIG4 , different contraction structures are appropriately arranged in the electrode flow channel in the bioparticle separation device. These contraction structures act as capillary valves with specific triggering pressure thresholds to achieve passive and accurate control of the flow path (e.g., the first path and the second path) of the liquid metal.

As an example, the electrode flow channel is connected to the sample flow channel through a square hole with a side length of 10 microns (see S3 in FIG. 4 ), and the hole has the highest trigger pressure threshold, which can be used as a shut-off valve to prevent the liquid metal from entering the sample flow channel after filling the first path. In addition, a contraction structure with a width of 80 microns can be placed at the branch of the electrode flow channel as a passive switching valve (see S2 in FIG. 4 ), and its trigger pressure threshold is stronger than the trigger pressure threshold of the electrode flow channel (see S1 in FIG. 4 ), but weaker than the trigger pressure threshold of the shut-off valve, so as to switch to the second path of the electrode flow channel after the liquid metal fills the first path of the electrode flow channel along the first path of the electrode flow channel.

In a possible implementation, a biological particle separation device is manufactured by a soft lithography process, and liquid metal can be injected into the liquid metal inlet of the biological particle separation device, and a capillary valve with different trigger pressure thresholds is used to integrate a large array of three-dimensional microelectrodes into the electrode pattern of the biological particle separation device. The process of self-assembly of the biological particle separation device includes: when the liquid metal is injected into the electrode flow channel and flows to the path branch, the passive switching valve prevents the liquid metal from entering the second path of the branch, and the liquid metal flows forward along the first path; when the liquid metal fills the first path of the electrode flow channel, the stop valve prevents the liquid metal from entering the sample flow channel after filling the first path of the electrode flow channel, and the passive switching valve switches the flow direction of the liquid metal from the first path to the second path of the branch; when the liquid metal enters the second path of the branch, the second path of the branch is used as the first path of the trunk, and the above process is repeated until the flowing liquid metal fills the electrode flow channel to form an electrode pattern.

It can be seen that the embodiments of the present disclosure can utilize the passive fluid control capability of the gradient threshold capillary valve to provide a simple and reliable liquid metal electrode structure and manufacturing method, thereby realizing self-assembly to form a three-dimensional liquid metal electrode array in a compact dielectrophoresis microfluidic device, so as to significantly improve the throughput of the bioparticle separation device and fill the gap between the clinical sample processing requirements and the throughput of the microfluidic bioparticle separation technology.

FIG5 shows a schematic diagram of the self-assembly workflow of the liquid metal electrode array of the embodiment of the present disclosure, which shows an example of the path switching process of the liquid metal in the process of filling the electrode flow channel under the capillary force shown in formulas (1) and (2). Among them, the cross-sectional shape of the current flow channel, the passive switching valve, and the stop valve is a rectangle with the same height, the width W ₁ of the electrode flow channel > the width W ₂ of the passive switching valve > the width W ₃ of the stop valve, so the cross-sectional area S1 of the electrode flow channel > the cross-sectional area S2 of the passive switching valve > the cross-sectional area S3 of the stop valve, so the triggering pressure threshold of the electrode flow channel < the triggering pressure threshold of the passive switching valve < the triggering pressure threshold of the stop valve. It should be understood that the present disclosure only takes a rectangle as an example, and does not specifically limit the shape of the current flow channel, the passive switching valve, and the stop valve.

First, when liquid metal is injected into the electrode flow channel and flows to the branch path (the junction of the first path and the second path in Figure 5), the liquid metal can choose to fill the electrode flow channel along the first path of the trunk or the second path of the branch. Since the triggering pressure threshold of the passive switching valve is higher than the triggering pressure threshold of the electrode flow channel, the passive switching valve prevents the liquid metal from entering the second path of the branch, allowing it to flow forward along the first path.

The liquid metal fills the first path and reaches the capillary valve structure with a strong trigger pressure threshold that serves as a stop valve. The passive switching valve still prevents the liquid metal from entering the branched second path.

As the flow pressure of the liquid metal increases, when the flow pressure of the liquid metal reaches the weak triggering pressure threshold of the passive switching valve, since the triggering pressure threshold of the stop valve is higher than the triggering threshold pressure of the passive switching valve, the liquid metal can break through the passive switching valve and begin to fill the second path of the branch, and the stop valve prevents the liquid metal from entering the sample flow channel.

When the liquid metal enters the branched second path, the branched second path can be used as the first path of the trunk, and the branch path on the path can be used as the second path. The above process is repeated, and the flowing liquid metal can autonomously fill the electrode flow channel with a complex pattern, thereby forming a compact and large three-dimensional electrode array. At the same time, this mechanism also greatly reduces the probability of the electrode flow channel not being filled and the liquid metal leaking into the sample flow channel. According to this mechanism, in the process of liquid metal autonomously filling the electrode flow channel, each pair of electrodes can have the same structure and working conditions, so the electrode array can be infinitely expanded.

It can be seen that compared with the related art, the electrode structure is simple and the manufacturing method is not practical. The embodiment of the present disclosure designs a structure for connecting large array electrodes and proposes a method for self-assembly of three-dimensional liquid metal alloy electrodes based on capillary action. It is so simple that complex three-dimensional liquid metal electrode patterns can be self-assembled by manually pushing the syringe to inject and drive, which improves the reliability and scalability of the manufacturing process. In addition, the embodiment of the present disclosure realizes the integration of a large array of three-dimensional liquid metal electrodes in the chip through accurate control of the flow of liquid metal, thereby generating a strong and uniform three-dimensional electric field in the height direction of the entire sample flow channel. This large-scale three-dimensional electric field enables efficient particle manipulation and provides a powerful technical means for the separation and analysis of biological samples.

In one possible implementation, the electrode flow channel adopts an asymmetric electrode setting, and each stop valve set on the positive electrode side corresponds to multiple stop valves set on the negative electrode side (for example, including 3, 4, 5, etc.), or each stop valve set on the negative electrode side corresponds to multiple stop valves set on the positive electrode side (for example, including 3, 4, 5, etc.).

For example, as shown in FIG2 , along the sample flow channel 103, the first pair of three-dimensional microelectrodes 401 can be set as a stop valve corresponding to N1 stop valves, the second pair of three-dimensional microelectrodes 401 can be set as a stop valve corresponding to N2 stop valves, and the third pair of three-dimensional microelectrodes 401 can be set as a stop valve corresponding to N3 stop valves. The values of N1, N2, and N3 can be the same or different. The embodiments of the present disclosure do not limit the number of stop valves in each pair of three-dimensional microelectrodes.

In order to generate the non-uniform electric field required for dielectrophoresis in the sample flow channel, each pair of microelectrodes adopts an asymmetric electrode arrangement. For example, a stop valve (such as a small hole) is arranged on the positive electrode side, and multiple stop valves (such as multiple small holes) are arranged on the negative electrode side; for another example, a stop valve (such as a small hole) is arranged on the negative electrode side, and multiple stop valves (such as multiple small holes) are arranged on the positive electrode side. It should be understood that the size of the small hole can be selected as needed, such as 10 microns, and the present disclosure does not limit the number and size of the small holes.

In practice, dielectrophoresis describes the translational motion of neutral particles in an inhomogeneous electric field due to dielectric polarization.

FIG6 shows a schematic diagram of a uniform sphere model and a single-shell sphere model according to an embodiment of the present disclosure. The principle of the dielectrophoresis effect will be described below in conjunction with FIG6 .

The particles in the biological fluid to be tested can be described based on a uniform sphere model, assuming that the uniform sphere model has dielectric properties as shown in the left part a of Figure 6. The time-averaged dielectrophoretic force on the uniform spherical particles suspended in the medium can be expressed as follows:

In formula (3), F _DEP represents the time-averaged dielectrophoretic force on a uniform spherical particle suspended in a medium, R is the particle radius, ε _m is the dielectric constant of the medium, and E is the electric field strength. is the gradient of the electric field, Re[·] represents the real part of the complex variable, and K _CM is the Clausius-Mossotti coefficient of uniform spherical particles, which can be expressed as follows:

In formula (4), is the complex dielectric constant of the particle that varies with frequency, is the complex dielectric constant of the medium that varies with frequency, and the complex dielectric constant of the polarizable particle is given by The complex dielectric constant of the medium is obtained by We get: where _σp represents the conductivity of the particle, σm represents the conductivity of the medium, _j is an imaginary unit, and ω is the angular frequency of the AC signal.

Most biological cells can be regarded as composed of a membrane that forms a vesicle structure, and their dielectric properties cannot be simplified by the above uniform sphere model. The single-shell sphere model can be used to characterize these particles, as shown in the right part b of Figure 6. The Clausius-Mossotti coefficient K _CM of the single-shell sphere particle can be expressed as follows:

In formula (5), the effective complex dielectric constant of the film particle is Instead of the complex dielectric constant of uniform spherical particles in formula (4), Complex dielectric constant of film particles It can be expressed as follows:

In formula (6), represents the complex dielectric constant of the cytoplasm, represents the complex dielectric constant of the membrane, R represents the outer radius of the single-shell dielectric model, d represents the membrane thickness of the single-shell dielectric model, and the complex dielectric constant of the cytoplasm Complex dielectric constant of the film Complex area specific capacitance of the membrane is the area specific membrane capacitance of the membrane, is the membrane area specific membrane conductivity. σ _cyto represents the conductivity of the cytoplasm, and σ _mem represents the conductivity of the cell membrane.

FIG7 shows a schematic diagram of the electric field strength simulation of the three-dimensional microelectrode of the embodiment of the present disclosure. As shown in FIG7, in order to generate the non-uniform electric field required for dielectrophoresis in the sample flow channel, each pair of grid units of the electrode flow channel shown in part A of FIG7 (for example, part 401 in FIG2) adopts an asymmetric electrode setting, a small hole is set on the positive electrode side, and multiple small holes are set on the negative electrode side accordingly. The size of these small holes as stop valves can be selected as needed, for example, 10 microns, and the present disclosure does not limit this. In addition, a small hole can be set on the positive electrode side, and N (N>1) small holes can be set on the negative electrode side. For example, N can take the value of 3, 4, 5, 6, etc., and the present disclosure does not specifically limit the number of small holes on the negative electrode side. The electric field simulation results formed by such an asymmetric electrode setting are shown in parts B and C of FIG7, wherein part B is a cross-sectional view of the electric field strength simulation results in the A-A section of the sample flow channel, and part C is a top view of the electric field strength simulation results in the sample flow channel. In the bioparticle separation device, multiple pairs of three-dimensional microelectrodes as shown in part A of Figure 7 are arranged in sequence along the sample flow channel. Part D of Figure 7 describes the simulation results of the movement trajectories of the bioparticles passing through the first pair of three-dimensional microelectrodes (see part i of D in the figure), the fifteenth pair of three-dimensional microelectrodes (see part ii of D in the figure), the 30th pair of three-dimensional microelectrodes (see part iii of D in the figure), and the 50th pair of three-dimensional microelectrodes (see part iv of D in the figure).

The simulation results show that the three-dimensional sidewall electrodes formed by liquid metal introduce a non-uniform strong electric field throughout the depth of the sample flow channel. This design has obvious advantages over the planar electrode device. First, the configuration of the sidewall electrodes does not interfere with sample imaging, facilitating real-time observation. Second, there is no need to lower the flow channel height to accommodate the range of action of the electrodes, which can achieve a higher separation flux. Furthermore, the high conductivity of the liquid metal can minimize circuit losses, allowing dielectrophoretic deflection at lower voltages.

To preliminarily verify this scheme, a bioparticle separation device integrating 50 pairs of three-dimensional electrodes was first tested to separate samples of HeLa cells and 10-μm polystyrene beads (PS beads) at 9 μL/min.

FIG8 shows a schematic diagram of a verification experiment of the bioparticle separation device of the embodiment of the present disclosure. Part A of FIG8 shows the trajectory of the mixed sample consisting of HeLa cells and polystyrene microbeads at the first pair of electrodes (see row i column of FIG8 ), the 30th pair of electrodes (see row ii column of FIG8 ) and the outlet (see row iii column of FIG8 ) in the absence of dielectrophoretic force; Part B of FIG8 shows the trajectory of the mixed sample consisting of HeLa cells and polystyrene microbeads at the first pair of electrodes (see row i column of FIG8 ), the 30th pair of electrodes (see row ii column of FIG8 ) and the outlet (see row iii column of FIG8 ) in the presence of dielectrophoretic force (e.g., dielectrophoretic force generated by an electric field with a magnitude of 40V and a frequency of 1MHz); Part C of FIG8 shows the separation efficiency of HeLa cells and polystyrene microbeads; Part D of FIG8 shows the purity of HeLa cells and polystyrene microbeads at the inlet and outlet.

It can be seen that FIG8 is a comparative experiment, showing the particle trajectory in the continuous separation with and without the dielectrophoretic force signal, and calculating the separation efficiency and purity of HeLa cells and polystyrene microbeads. Among them, using the biological particle separation device of the embodiment of the present disclosure, under the influence of the dielectrophoretic force, about 99.31% of the polystyrene microbeads are deflected and move to _O2 , while about 89.29% of the HeLa cells move out of _O1 . At the same time, the purity of HeLa cells in _O1 is as high as 99.19%, and the purity of polystyrene microbeads in _O2 is 85.47%. Compared with the initial ratio of 2:1 of the two particles, the degree of enrichment is significant.

It can be seen that the biological particle separation device according to the embodiment of the present disclosure can efficiently and accurately separate different types of particles according to the deflection differences of different particles under the action of dielectrophoretic force.

In order to further verify the effectiveness of the large array three-dimensional liquid metal microelectrode structure and processing method proposed in the present disclosure, polystyrene microspheres with a diameter of 10 microns were used as test samples and passed into a bioparticle separation device integrated with 5000 pairs of three-dimensional microelectrodes at a flow rate of microliters/minute. FIG9 shows a schematic diagram of another verification experiment of the bioparticle separation device of the embodiment of the present disclosure, wherein part a of FIG9 shows the particle trajectories of the polystyrene microsphere sample when passing through the first pair (i), the five hundredth pair (ii) and the five thousandth pair (iii) of electrodes under the conditions of a voltage of 20 V _pp and a frequency of 100 kHz; part b of FIG9 shows the probability density function E _index of the particle trajectories of the polystyrene microsphere sample when passing through the first pair, the five hundredth pair and the five thousandth pair of electrodes.

As shown in part a(i) of Figure 9, when the sample passes through the first pair of three-dimensional microelectrodes, due to the high sample flow rate, the sample particles quickly pass through the effective electric field area, and almost no particle trajectory deflection caused by the dielectrophoretic force is observed. As shown in part a(ii) of Figure 9, due to the cumulative effect of the three-dimensional microelectrode array on the dielectrophoretic deflection, when the sample passes through the 500th pair of three-dimensional microelectrodes, the particle trajectory is deflected by about 6.2 microns, but the deflection distance is small and insufficient to achieve effective dielectrophoretic particle separation. Finally, as shown in part a(iii) of Figure 9, when the sample passes through the 5000th pair of three-dimensional microelectrodes, obvious particle trajectory deflection is observed, and the deflection distance is about 40 microns, which is 6 times higher than when passing through the 500th pair of three-dimensional microelectrodes, which is enough to affect the outlet of the sample flow.

In the above-mentioned verification experiment integrating 5,000 pairs of microelectrode devices, an effective dielectrophoretic deflection of about 40 microns was achieved at a sample flow rate of microliters per minute, greatly improving the sample separation throughput.

In summary, the biological particle separation device of the embodiment of the present disclosure adopts the co-design of the electrode flow channel and the sample flow channel, and the capillary valves with different trigger pressure thresholds are set in the electrode flow channel to realize the path connection and switching of the electrode flow channel, so as to produce a three-dimensional microelectrode pair array that is self-aligned with the sample flow channel; the biological particle separation device of the embodiment of the present disclosure uses capillary action to realize accurate control of the flow of liquid metal, which is as simple as a hand-pushing syringe to drive the liquid metal flow, and it can self-assemble into a complex electrode pattern, thereby realizing the integration of a high-density large array of three-dimensional liquid metal electrodes in a microfluidic chip. Using this biological particle separation device integrated with a large array of three-dimensional liquid metal electrodes, high-throughput dielectrophoresis microfluidic separation can be performed on the biological particle samples to be detected. By integrating a large array of three-dimensional electrodes in the microfluidic chip, the cumulative superposition of the dielectrophoretic force effect is realized, thereby realizing high-throughput progressive particle separation.

Compared with the related art, the mesophoretic microfluidic method is limited by its low separation efficiency and flux at high sample flow rates and high sample concentrations. The disclosed embodiment achieves continuous, progressive and high-throughput separation of biological particles by integrating a large array of three-dimensional liquid metal electrodes. Through the large number of electric field gradient fields generated by the large array electrodes in the microchannel, the effect of the dielectrophoretic force is accumulated with the number of electrode pairs, and the sample particles can be gradually deflected at high flow rates and high concentrations, thereby significantly improving the separation flux.

In summary, the technical solution of the present invention provides a large array three-dimensional liquid metal microelectrode structure and manufacturing method, improves separation flux, and realizes efficient particle manipulation, which overcomes the limitations of the prior art and brings significant beneficial technical effects, with the number of arrays increased by at least times and the separation flux increased by 10 times. These effects make the present invention an innovative technology with important application potential and commercial value.

Those skilled in the art will appreciate that, in the above method of specific implementation, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of the steps should be determined by their functions and possible internal logic.

The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims (10)

1. A biological particle separation device, characterized in that the device includes: Microfluidic channel, the microfluidic channel includes a particle suspension inlet, a focusing sheath liquid inlet, a sample flow channel, a particle suspension outlet, and a focusing sheath liquid outlet. The particle suspension inlet and the focusing sheath liquid inlet pass through the The sample flow channel connects the particle suspension outlet and the focusing sheath liquid outlet; A liquid metal inlet, an electrode flow channel, and a liquid metal outlet. The liquid metal inlet is connected to the liquid metal outlet through the electrode flow channel. The electrode flow channel is used to form at least one group of three-dimensional microelectrodes with opposite polarities; A base used to fix the microfluidic channel, the liquid metal inlet, the electrode flow channel, and the liquid metal outlet. 2. The device according to claim 1, wherein the electrode flow channel includes capillary valves with different triggering pressure thresholds, and the capillary valve is used to control the flow direction of liquid metal in the electrode flow channel. 3. The device according to claim 2, wherein the capillary valve includes a stop valve and a passive switching valve, the electrode flow channel is connected to the sample flow channel through the stop valve, and the electrode flow channel The first path is connected to the second path of the branch through the passive switching valve. The cross-sectional area of the electrode flow channel is larger than the cross-sectional area of the passive switching valve. The cross-sectional area of the passive switching valve is larger than the cross-sectional area of the stop valve. cross-sectional area. 4. The device according to claim 3, wherein the stop valve is used to prevent the liquid metal from entering the sample flow channel after filling the first path of the electrode flow channel; The passive switching valve is used to prevent the liquid metal from entering the second path of the branch when the liquid metal does not fill the first path of the electrode flow channel, and When the liquid metal fills the first path of the electrode flow channel, the flow direction of the liquid metal is switched from the first path to the branched second path. 5. The device according to any one of claims 2-4, characterized in that the electrode flow channel adopts an asymmetric electrode arrangement, and each stop valve provided on the positive electrode side corresponds to a plurality of stop valves provided on the negative electrode side, Alternatively, each stop valve provided on the negative electrode side corresponds to multiple stop valves provided on the positive electrode side. 6. The device according to any one of claims 1-4, characterized in that the particle suspension inlet and the particle suspension outlet are connected to a microfluidic pump through a plastic hose to pass through the microfluidic A pump controls the flow of a particle suspension in a microfluidic channel. 7. The device according to any one of claims 1 to 4, wherein the liquid metal includes at least one of indium, tin, cadmium, bismuth, lead, and gallium. 8. A processing method for a biological particle separation device, characterized in that the method includes: The biological particle separation device according to any one of claims 1-7 is produced by soft photolithography process; Liquid metal is injected into the liquid metal inlet of the biological particle separation device, and capillary valves with different triggering pressure thresholds are used to integrate a large array of three-dimensional microelectrodes into the self-assembled electrode pattern of the biological particle separation device. 9. The method according to claim 8, wherein the capillary valve includes a stop valve and a passive switching valve, the electrode flow channel is connected to the sample flow channel through the stop valve, and the electrode flow channel The first path is connected to the second path of the branch through the passive switching valve. The cross-sectional area of the electrode flow channel is larger than the cross-sectional area of the passive switching valve. The cross-sectional area of the passive switching valve is larger than the cross-sectional area of the stop valve. cross-sectional area; The self-assembly process of the biological particle separation device includes: When liquid metal is injected into the electrode flow channel and flows to the path branch, the passive switching valve blocks the liquid metal from entering the second path of the branch, and the liquid metal flows forward along the first path; When the liquid metal fills the first path of the electrode flow channel, the stop valve prevents the liquid metal from entering the sample flow channel, and the passive switching valve switches the flow direction of the liquid metal from the first path to the second branched path. path; After the liquid metal enters the second path of the branch, the second path of the branch is used as the first path of the trunk, and the above process is repeated until the flowing liquid metal fills the electrode flow channel to form an electrode pattern. 10. A microfluidic chip, characterized by comprising the biological particle separation device according to any one of claims 1-7.