Microfluidic chip with mixing chamber and microfluidic device

Abstract

The present disclosure relates to a microfluidic chip and a microfluidic device with a mixing chamber. The microfluidic chip comprises a sample inlet for receiving a sample microfluid, a sample channel in communication with the sample inlet, a capillary pump in communication with the sample channel, and a reaction unit comprising: an annular reaction channel in communication with the sample channel via a splitting channel, the reaction channel comprising a photo-deformable material; a communication structure in communication with the reaction channel at one end and kept in communication with the atmosphere at the other end, such that the sample microfluid can self-seal the communication structure after entering the communication structure, wherein a first connection point of the splitting channel and the reaction channel and a second connection point of the reaction channel and the communication structure are spaced apart from each other; and a mixing chamber provided at the first connection point and in communication with the splitting channel and the reaction channel, wherein a cross-sectional area of the sample channel is greater than a cross-sectional area of the reaction channel, which is greater than a cross-sectional area of the communication structure and a cross-sectional area of the mixing chamber, and the cross-sectional area of the mixing chamber is greater than a cross-sectional area of the splitting channel.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of microfluidics, and more particularly, to a microfluidic chip and an operating method thereof, a microfluidic device, and a microfluidic apparatus. BACKGROUND

[0002] Microfluidics can integrate sample preparation, reaction, separation, detection and other complex microfluidic operations of biological, chemical and medical analysis processes on a chip of tens of square centimeters, so as to automatically complete the whole analysis process, and has the advantages of high integration degree and large processing throughput. In a traditional microfluidic chip, in order to realize the metering of a trace sample, a complex fluid channel needs to be designed, and a pump valve assembly driven by external power needs to be arranged to drive and control the movement of the fluid. The structure is complex, the operation is cumbersome, and it is difficult to realize portability. Moreover, because the fluid driven by such a pump valve assembly must be in a continuous state, the whole pre-channel needs to be filled to complete the metering operation at the rear end, so the sample loss is large. Therefore, the microfluidic chip based on the pump valve assembly driven by external power cannot realize the metering of a trace sample in a true sense.

[0003] Polymerase chain reaction (PCR) is a molecular biology technique for amplifying specific DNA fragments, which can be regarded as a special DNA replication in vitro. The biggest feature of PCR is that it can greatly increase the amount of trace DNA, so it is widely used in medical detection and other fields. However, for PCR detection technology, the conventional PCR detection equipment is large in size, which is difficult to meet the use requirements in the field of point-of-care testing (POCT). Moreover, the PCR reaction conditions are relatively harsh, and once the control is not accurate, the detection result will be affected, so the sample is usually sent to a special detection laboratory or a clinical laboratory for detection. SUMMARY

[0004] A brief summary of the present disclosure is given in the following to provide a basic understanding of some aspects of the present disclosure. However, it should be understood that this summary is not a comprehensive summary of the present disclosure. It is not intended to determine the key or important parts of the present disclosure, nor to limit the scope of the present disclosure. Its purpose is only to give some concepts of the present disclosure in a simplified form as a prelude to the more detailed description given later.

[0005] According to an aspect of the present disclosure, there is provided a microfluidic chip, comprising a microfluidic unit, the microfluidic unit comprising: a sample inlet configured to receive a sample microfluid; a sample channel configured to communicate with the sample inlet to receive the sample microfluid from the sample inlet; a capillary pump configured to communicate with the sample channel to draw the sample microfluid through and out of the sample channel; and one or more reaction units, each reaction unit comprising: a reaction channel in a ring arrangement, configured to communicate with the sample channel via a distribution channel corresponding to the reaction unit between the sample inlet and the capillary pump to receive a preset volume of the sample microfluid corresponding to the reaction unit from the sample channel, wherein the reaction channel comprises a photo-deformable material such that the microfluid is driven through the reaction channel under the action of an asymmetrically photo-deformed Laplace pressure difference of the reaction channel; a communication structure configured to communicate with the reaction channel at one end and to keep communication with the atmosphere at the other end, such that the sample microfluid can self-seal the communication structure after entering the communication structure from the distribution channel via the reaction channel, wherein a first connection point of the distribution channel and the reaction channel and a second connection point of the reaction channel and the communication structure are spaced apart from each other along a longitudinal center line of the reaction channel; and a mixing chamber provided at the first connection point and configured to communicate with the distribution channel and the reaction channel, respectively, the microfluid in the reaction channel being mixed in the mixing chamber, wherein a cross-sectional area of the sample channel is greater than a cross-sectional area of the reaction channel, the cross-sectional area of the reaction channel is greater than a cross-sectional area of the communication structure, the cross-sectional area of the reaction channel is greater than a cross-sectional area of the mixing chamber, and the cross-sectional area of the mixing chamber is greater than a cross-sectional area of the distribution channel.

[0006] According to another aspect of the present disclosure, there is provided a microfluidic device, comprising a microfluidic chip according to an embodiment of the present disclosure and a light source configured to provide light illumination to the microfluidic chip to control movement of microfluid in the microfluidic chip.

[0007] According to yet another aspect of the present disclosure, there is provided a microfluidic device for isothermal polymerase chain reaction detection, comprising: a light control module comprising a light source configured to provide light illumination to a microfluidic chip to control movement of microfluidics in the microfluidic chip, the microfluidics in the microfluidic chip being optically drivable; a detection module configured to perform detection required for isothermal polymerase chain reaction detection on the microfluidic chip; a movement module configured to move the microfluidic chip to adjust relative position of the microfluidic chip and the light source such that the microfluidic chip is selectively locally illuminated by the light source to cause the microfluidics in the microfluidic chip to be optically driven, and the movement module is further configured to move the microfluidic chip to adjust relative position of the microfluidic chip and the detection module such that the microfluidic chip is subjected to detection by the detection module; a temperature control module configured to control temperature of the microfluidic chip to be maintained at a temperature required for isothermal polymerase chain reaction detection, wherein the light control module is fixed above the movement module, the detection module is fixed above the movement module and spaced apart from the light control module, and the temperature control module is arranged in the movement module.

[0008] Other features of the present disclosure, and their advantages, will become more apparent in the light of the following detailed description of exemplary embodiments of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The embodiments set forth in the drawings are illustrative in nature and are not intended to limit the present disclosure. When read in conjunction with the following detailed description, those skilled in the art will understand the following detailed description of the exemplary embodiments to clearly understand the principles of the present disclosure, in which like reference characters indicate like structures, and in which:

[0010] Figures 1 to 5 is a schematic diagram showing a microfluidic chip according to some embodiments of the present disclosure;

[0011] Figure 6 is a schematic diagram showing a non-limiting example process of optically driving microfluidics in a microfluidic chip according to embodiments of the present disclosure;

[0012] Figure 7 and Figure 8 is a flowchart showing a method of operating a microfluidic chip according to some embodiments of the present disclosure;

[0013] Figures 9 to 13 is a schematic diagram showing a microfluidic device according to some embodiments of the present disclosure;

[0014] Figure 14 is a schematic diagram showing a microfluidic device for constant-temperature PCR detection according to some embodiments of the present disclosure;

[0015] Figure 15 is a schematic diagram showing a microfluidic device for constant-temperature PCR detection according to some embodiments of the present disclosure; Figure 14 is a schematic diagram showing a moving module of the microfluidic device shown in

[0016] Figure 16 is a schematic diagram showing a light control module of the microfluidic device shown in Figure 14 is a schematic diagram showing a light control module of the microfluidic device shown in DETAILED DESCRIPTION

[0017] Various exemplary embodiments of the present disclosure will be described in detail herein below with reference to the drawings. It should be noted that the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments do not limit the scope of the present disclosure unless otherwise specifically stated.

[0018] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the scope of the present disclosure, its application, or uses. That is, the structural and methodological aspects of the present disclosure are set forth in an exemplary fashion to illustrate various embodiments of the structural and methodological aspects of the present disclosure. However, those skilled in the art will appreciate that they are merely illustrative of the exemplary manners in which the present disclosure can be implemented and are not exhaustive. Moreover, the drawings are not necessarily to scale and some features can be exaggerated in order to illustrate details of specific components.

[0019] In addition, techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein because such can be found in the pertinent literature.

[0020] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0021] The present disclosure provides, in one aspect, a microfluidic chip that can drive fluid by the action of Laplace pressure difference (capillary force) generated by a capillary pump, so that non-contact sampling of a micro-sample can be achieved. Since the microfluidic chip according to the present disclosure does not need to rely on an external powered pump valve assembly to drive fluid, the continuity requirement for the fluid is low, the sample loss is low, and the number of components and the overall volume of the microfluidic chip and its supporting equipment are also small. The microfluidic chip according to various embodiments of the present disclosure will be described in detail below with reference to the drawings. It should be understood that the actual microfluidic chip can also include other components, but in order not to obscure the gist of the present disclosure, these other components are not discussed herein and are not shown in the drawings. It should also be understood that various embodiments can be combined with each other, but for the sake of simplicity of illustration, only some combinations of these embodiments are exemplarily illustrated in the drawings.

[0022] Figure 1 A microfluidic chip 100 according to some embodiments of the present disclosure is shown. As shown, the microfluidic chip 100 includes a microfluidic unit 100U, which includes a sample inlet 101, a sample channel 102, a capillary pump 103, and reaction units 110A-110B. It should be understood that while two reaction units are shown, this is merely exemplary and not limiting, and the microfluidic chip 100 can include one, two, three, or more reaction units as desired. Figure 1 Figure 1

[0023] The sample inlet 101 is configured to receive a sample microfluid. The sample channel 102 is configured to communicate with the sample inlet 101 to receive the sample microfluid from the sample inlet 101. For example, the sample microfluid can be dropped at the sample inlet 101 to fill the sample inlet 101, which in turn extends into the sample channel 102 for a distance. In this context, a cross-section refers to a plane in which the width and depth lie, which is perpendicular to the direction of the length. The plane in which the figures are illustrated in this context is the plane in which the width and length lie, but it is noted that these figures are provided for illustrative purposes and are not necessarily drawn to scale. In some embodiments, the cross-sectional area of the sample inlet 101 can be greater than or equal to the cross-sectional area of the sample channel 102. This can facilitate the spontaneous entry of the sample microfluid from the sample inlet 101 into the sample channel 102. It should be understood that the present disclosure is not limited to dropping the sample microfluid into the sample inlet 101. In some embodiments, the sample inlet 101 can also communicate with other channels, chambers, etc. on the microfluidic chip 100 to receive the sample microfluid therefrom. For example, the sample inlet 101 can communicate with a pre-reaction unit to receive the sample microfluid therefrom for further processing after the reaction is completed. Figures 1 to 5

[0024] The capillary pump 103 is configured to communicate with the sample channel 102 to draw the sample microfluid through and out of the sample channel 102. The capillary pump 103 can generally be composed of a plurality of capillary channels, each of which has a cross-sectional area that is much smaller than the cross-sectional area of the various channels of the microfluidic chip 100, and the ends of which are configured to be open to the atmosphere. Thus, after the sample microfluid enters the sample channel 102, it is driven through the sample channel 102 by the Laplace pressure differential created by the capillary pump 103 and is ultimately drawn away by the capillary pump 103. In some embodiments, for example as shown in FIG. 1, the capillary pump 103 can be configured to draw the sample microfluid through the sample channel 102 and into a reaction unit 110A-110B. Figure 1 ​​​As shown, the capillary pump 103 can include a plurality of microfluidic channels arranged in a tree-like manner. Such a structure can effectively increase the capillary force generated by the capillary pump in one aspect and increase the amount of liquid that can be accommodated by the capillary pump in another aspect, further improving the utilization of the microfluidic chip 100. It should be understood that the structure of the capillary pump 103 illustrated is merely for providing an illustrative example and is not intended to limit the present disclosure.

[0025] Each reaction unit includes a reaction channel, a communication structure, and a mixing chamber. The reaction channel is arranged in a ring shape. In this context, the ring shape only requires the channel to be connected end to end, and there is no limitation on the profile of the channel, and the profile of the ring-shaped channel may, for example, be various suitable shapes such as a polygon such as a triangle, a quadrilateral, a pentagon, a circle, an ellipse, etc., such as the profile of the ring-shaped reaction channel is non-limitingly illustrated as a rectangle in the drawings herein. The reaction channel is configured to communicate with the sample inlet channel via the sampling channel corresponding to the reaction unit between the sample inlet and the capillary pump to receive a preset volume of sample microfluid corresponding to the reaction unit from the sample inlet channel. The reaction channel includes a photo-deformable material so that the microfluid can be driven (also referred to as photo-driven herein) through the reaction channel under the action of the asymmetric Laplace pressure difference generated by the photo-deformation of the reaction channel (the process of photo-driving microfluid will be described in detail later). The communication structure is configured to communicate with the reaction channel at one end and maintain communication with the atmosphere at the other end, so that the sample microfluid can self-seal the communication structure after entering the communication structure from the sampling channel via the reaction channel. The first connection point of the sampling channel and the reaction channel and the second connection point of the reaction channel and the communication structure are spaced apart from each other along the longitudinal center line of the reaction channel. The longitudinal center line of the reaction channel is a line passing through the center of each cross section of the reaction channel in the length direction of the reaction channel. It should be understood that in this context, the distance between one point and another point and the point of symmetry of one point with respect to another point mentioned later can be considered by hypothetically unfolding the ring-shaped reaction channel into a straight line. Figure 6 The process of photo-driving microfluid is described in detail herein). The communication structure is configured to communicate with the reaction channel at one end and maintain communication with the atmosphere at the other end, so that the sample microfluid can self-seal the communication structure after entering the communication structure from the sampling channel via the reaction channel. The first connection point of the sampling channel and the reaction channel and the second connection point of the reaction channel and the communication structure are spaced apart from each other along the longitudinal center line of the reaction channel. The longitudinal center line of the reaction channel is a line passing through the center of each cross section of the reaction channel in the length direction of the reaction channel. It should be understood that in this context, the distance between one point and another point and the point of symmetry of one point with respect to another point mentioned later can be considered by hypothetically unfolding the ring-shaped reaction channel into a straight line.

[0026] For example, as Figure 1As shown, the reaction unit 110A includes a reaction channel 1041 in a ring arrangement. The reaction channel 1041 is configured to communicate with the sample channel 102 between the sample inlet 101 and the capillary pump 103 via a split channel 1051 to receive a first preset volume of sample microfluidics from the sample channel 102. The reaction channel 1041 includes a photo-deformable material enabling the microfluidics to be driven through the reaction channel 1041 under the action of an asymmetric Laplace pressure difference generated by photo-deformation of the reaction channel 1041. The reaction unit 110B includes a reaction channel 1042 in a ring arrangement. The reaction channel 1042 is configured to communicate with the sample channel 102 between the sample inlet 101 and the capillary pump 103 via a split channel 1052 to receive a second preset volume of sample microfluidics from the sample channel 102. The reaction channel 1042 includes a photo-deformable material enabling the microfluidics to be driven through the reaction channel 1042 under the action of an asymmetric Laplace pressure difference generated by photo-deformation of the reaction channel 1042.

[0027] The reaction unit 110A further includes a communication structure 1061 configured to communicate with the reaction channel 1041 at one end and to remain in communication with the atmosphere at the other end, enabling the sample microfluidics to self-seal the communication structure 1061 after entering the communication structure 1061 from the split channel 1051 via the reaction channel 1041. The reaction unit 110B further includes a communication structure 1062 configured to communicate with the reaction channel 1042 at one end and to remain in communication with the atmosphere at the other end, enabling the sample microfluidics to self-seal the communication structure 1062 after entering the communication structure 1062 from the split channel 1052 via the reaction channel 1042.

[0028] The first connection point CP11 of the split channel 1051 and the reaction channel 1041 and the second connection point CP21 of the reaction channel 1041 and the communication structure 1061 are spaced apart from each other along the longitudinal center line of the reaction channel 1041. The first connection point CP12 of the split channel 1052 and the reaction channel 1042 and the second connection point CP22 of the reaction channel 1042 and the communication structure 1062 are spaced apart from each other along the longitudinal center line of the reaction channel 1042.

[0029] The reaction unit 110A further includes a mixing chamber 1081 disposed at the first connection point CP11 and configured to respectively communicate with the sampling channel 1051 and the reaction channel 1041. The geometric center of the mixing chamber 1081 can coincide with the intersection of the longitudinal centerline of the reaction channel 1041 and the longitudinal centerline of the sampling channel 1051, for example. Microfluidics in the reaction channel 1041 can mix in the mixing chamber 1081. The reaction unit 110B further includes a mixing chamber 1082 disposed at the first connection point CP12 and configured to respectively communicate with the sampling channel 1052 and the reaction channel 1042. The geometric center of the mixing chamber 1082 can coincide with the intersection of the longitudinal centerline of the reaction channel 1042 and the longitudinal centerline of the sampling channel 1052, for example. Microfluidics in the reaction channel 1042 can mix in the mixing chamber 1082. In some embodiments, the mixing chamber 1081 (1082) can be formed as part of the reaction channel 1041 (1042).

[0030] In the microfluidic chip 100, the cross-sectional area of the sampling channel 102 is greater than the cross-sectional area of the reaction channels 1041-1042. This can facilitate microfluidics to enter the reaction channels 1041-1042 from the sampling channel 102 under the action of Laplace pressure difference. The cross-sectional area of the reaction channels 1041-1042 is greater than the cross-sectional area of the communication structures 1061-1062. This can facilitate microfluidics to enter the communication structures 1061-1062 from the reaction channels 1041-1042 under the action of Laplace pressure difference. The cross-sectional area of the reaction channels 1041-1042 is greater than the cross-sectional area of the mixing chambers 1081-1082. In some embodiments, the width of the mixing chamber 1081 (1082) is greater than the width of the reaction channel 1041 (1042), for example, can be twice or more than the width of the reaction channel 1041 (1042). As a result, the depth of the mixing chamber 1081 (1082) can be much smaller than the depth of the reaction channel 1041 (1042). In addition, the cross-sectional area of the mixing chambers 1081-1082 is greater than the cross-sectional area of the sampling channels 1051-1052. The sampling channels 1051-1052 can serve as a liquid bridge between the reaction channels 1041-1042 and the sampling channel 102.

[0031] Thus, after the sample microfluid enters the sample inlet channel 102 from the sample inlet 101, the sample microfluid travels through the sample inlet channel 102 under the action of the Laplace pressure difference generated by the capillary pump 103, and when reaching the connection point of each sample distribution channel 1051-1052 and the sample inlet channel 102, the sample microfluid enters the corresponding mixing chamber 1081-1082 and the reaction channel 1041-1042 through each sample distribution channel 1051-1052 under the action of the Laplace pressure difference generated by the fact that the cross-sectional area of the sample inlet channel 102 is greater than the cross-sectional area of the reaction channel 1041-1042.

[0032] When the sample microfluid enters the sample distribution channel 1051(1052) to reach the first connection point CP11(CP12) of the sample distribution channel 1051(1052) and the reaction channel 1041(1042), the sample microfluid flows along the reaction channel 1041(1042) in both directions (in the direction of the arrow A1(A2) and in the direction of the arrow B1(B2)) from the first connection point CP11(CP12). Figure 1The sample microfluid can enter the communication structure 1061(1062) when it reaches the second connection point CP21(CP22) of the reaction channel 1041(1042) and the communication structure 1061(1062) due to the Laplace pressure difference caused by the cross-sectional area of the reaction channel 1041(1042) being larger than that of the communication structure 1061(1062). Once the sample microfluid enters the communication structure 1061(1062) with a small cross-sectional area, a liquid column is formed to seal the communication structure 1061(1062). When the communication structure 1061(1062) is sealed, the gas in the reaction channel 1041(1042) can no longer be discharged from the communication structure 1061(1062), and the sample microfluid cannot move further in the reaction channel 1041(1042) to overcome the gas pressure. Therefore, the sample microfluid can move at most to the minimum distance between the first connection point CP11(CP12) and the second connection point CP21(CP22) along the longitudinal center line of the reaction channel 1041(1042) in the first direction (e.g., clockwise direction) between the first connection point and the second connection point and in the second direction (e.g., counterclockwise direction) opposite to the first direction between the first connection point and the second connection point after the sample microfluid enters the reaction channel 1041(1042) from the first connection point CP11(CP12), and the sample microfluid that fails to enter the reaction channel 1041(1042) and remains in the sample inlet channel 102 will be sucked away by the capillary pump 103, leaving a section of sample microfluid between the second connection point CP21(CP22) and the second connection point CP21(CP22) on the longitudinal center line of the reaction channel 1041(1042) about the symmetry point CP21'(CP22') of the first connection point CP11(CP12) of the second connection point CP21(CP22). It can be seen that such a volume taking process is spontaneously realized under the action of the Laplace pressure difference, without the need for the driving of any external power pump valve assembly, and without the need for the sample microfluid to continuously fill the channel in front of the reaction unit 110A-110B.

[0033] By the above metering process, a segment of sample microfluidic between the second connection point CP21 and the symmetry point CP21' (via the first connection point CP11) can be held in the reaction unit 110A, and a segment of sample microfluidic between the second connection point CP22 and the symmetry point CP22' (via the first connection point CP12) can be held in the reaction unit 110B. The splitting channels 1051-1052 and the communication structures 1061-1062 can be the thinnest channels in the microfluidic chip 100, and the mixing chambers 1081-1082 can be the shallowest channels in the microfluidic chip 100, their volumes can be configured to be negligible compared to the volume of the reaction channel 1041 between CP21 and CP21' and the volume of the reaction channel 1042 between CP22 and CP22'. Therefore, the first preset volume of sample microfluidic metered by the reaction unit 110A can be substantially equal to the volume of the reaction channel 1041 between CP21 and CP21', which is determined based on the difference between twice the minimum distance between the first connection point CP11 and the second connection point CP21 along the longitudinal center line of the reaction channel 1041 and the length of the mixing chamber 1081 along the longitudinal center line of the reaction channel 1041, and the cross-sectional area of the reaction channel 1041; the second preset volume of sample microfluidic metered by the reaction unit 110B can be substantially equal to the volume of the reaction channel 1042 between CP22 and CP22', which is determined based on the difference between twice the minimum distance between the first connection point CP21 and the second connection point CP22 along the longitudinal center line of the reaction channel 1042 and the length of the mixing chamber 1082 along the longitudinal center line of the reaction channel 1042, and the cross-sectional area of the reaction channel 1042. In some embodiments, the reaction units 110A-110B are configured to receive the same preset volume of sample microfluidic from the sample inlet channel 102, for example as shown in Figure 1 . (assuming the cross-sectional areas of the reaction channels 1041-1042 are the same in Figure 1 . In other embodiments, the reaction units 110A-110B are configured to receive different preset volumes of sample microfluidic from the sample inlet channel 102, for example as shown in Figure 2 . (assuming the cross-sectional areas of the reaction channels 1041-1042 are the same in Figure 2 .

[0034] In combination with reference to Figure 1 and Figure 6 , in some embodiments, the microfluidic chip 100 can include a substrate 10 on which the sample inlet 101 and the groove in communication with the sample inlet 101 are disposed, and a photodeformable film 20 attached to the substrate 10 (for the sake of clarity, only the substrate 10 is shown in Figures 1 to 5 , and the photodeformable film 20 is not shown in Figures 1 to 5The light-induced deformation film 20 is not shown in Figs. 1-3, but it at least partially covers the grooves to form closed channels 30 together with the grooves, so that the microfluids can be driven through the closed channels 30 under the action of the asymmetric Laplace pressure difference caused by the light-induced deformation of the closed channels 30. The closed channels 30 can at least provide the reaction channels 1041-1042. In some embodiments, the closed channels 30 can also provide other channels of the microfluidic chip 100 such as the sample inlet channel 102, the sample distribution channels 1051-1052, the connection structures 1061-1062, etc., but even if the upper surfaces of these other channels are formed by the light-induced deformation film 20, the fluids in them will not be optically driven when their upper surfaces are not light-induced deformed. For example, the grooves can be machined on the substrate 10 as the bottom and side surfaces of the closed channels 30 by high-precision Computerized Numerical Control (CNC) machining, and after the CNC machining is completed, the light-induced deformation film 20 is covered on the grooves as the upper surface of the closed channels 30 to obtain the complete channel structure. In some embodiments, in order to reduce the difficulty of CNC machining and to improve the accuracy of sampling, the cross-sectional shape of the channels can be rectangular. However, this is only exemplary and not limiting, and the channels can also have other suitable cross-sectional shapes. In some examples, the substrate 10 can be a substrate made of acrylic, which not only meets the requirements of the material for the microfluidic chip and the requirements of the material for CNC machining, but also has good transparency, which is more conducive to observing the state of the microfluids in the microfluidic chip. The light-induced deformation material can be any suitable light-induced deformation material known at present or to be developed in the future. In some examples, the light-induced deformation material can include a light-induced deformation liquid crystal polymer material, and for example, a whole film made of the light-induced deformation liquid crystal polymer material can be used as the light-induced deformation film 20. In some examples, the light-induced deformation liquid crystal polymer material can include a light-responsive linear liquid crystal polymer material with a polyoctenamer main chain and an azobenzene-containing side chain. In some embodiments, the substrate 10 and the light-induced deformation film 20 can be recyclable and reusable. For example, an acrylic substrate that has been used but is not damaged can be recycled as a brand new component after thorough cleaning and drying treatment to produce a new microfluidic chip, and the film made of the light-induced deformation liquid crystal polymer material can also be dissolved and extracted to obtain the original material to be re-prepared into a film for producing a new microfluidic chip.

[0035] When certain illumination conditions are met, the photo-morphing material (e.g., photo-morphing film 20) can undergo local photo-morphing, resulting in a change in the cross-sectional area of the local channel. Under the action of Laplace pressure difference, the fluid in the channel will move towards the direction of decreasing cross-sectional area. In some embodiments, the photo-morphing material (e.g., photo-morphing film 20) is configured to expand in response to being illuminated, such that the portion of the reaction channel 1041-1042 under illumination has a larger cross-sectional area than when not under illumination, thereby driving the microfluid in the reaction channel 1041-1042 towards the direction of decreasing illumination intensity. In some embodiments, the photo-morphing material (e.g., photo-morphing film 20) is configured to contract in response to being illuminated, such that the portion of the reaction channel 1041-1042 under illumination has a smaller cross-sectional area than when not under illumination, thereby driving the microfluid in the reaction channel 1041-1042 towards the direction of increasing illumination intensity.

[0036] Reference is made to Figure 6 , which shows the plane in which the length and depth lie, and illustrates the case of the photo-morphing film 20 expanding under light, as a non-limiting example: the microfluid 40 is in position a (represented by the position of the left end face of the microfluid 40), and the cross-sectional areas of the portions of the closed channel 30 are initially the same; after the photo-morphing film 20 at position a is illuminated with light capable of causing the photo-morphing film 20 to expand, due to the portion of the photo-morphing film 20 at position a expanding under light, the cross-sectional area of the portion of the closed channel 30 at position a increases, which is greater than the cross-sectional area of the portion of the closed channel 30 at position b, thereby the asymmetric photo-morphing of the closed channel 30 at position a and position b generates a Laplace pressure difference, and under the action of the Laplace pressure difference, the microfluid 40 spontaneously moves from the position a with a larger cross-sectional area to the position b with a smaller cross-sectional area, thereby achieving photo-driven of the microfluid 40. Using such a principle, the photo-driven of the microfluid 40 can be precisely controlled by controlling the position and intensity of the illumination. Such a photo-driven method does not require an external driving device, and can achieve contactless driving of the microfluid using only a light source that meets the conditions. Moreover, the driving precision is also high.

[0037] In some embodiments, for example as shown in Figure 1 , the communication structure 1061(1062) includes a balance channel 10611(10621) in communication with the corresponding reaction channel 1041(1042) at one end and in communication with the atmosphere at the other end, and the cross-sectional area of the balance channel 10611(10621) is smaller than that of the reaction channel 1041(1042). In some examples, the end of the balance channel 10611(10621) is formed to be open to the atmosphere, as shown in Figure 1as shown. In some examples, the end of the balancing channel 10611 (10621) includes a balancing cavity 10612 (10622) with a vertical through-hole to communicate with the atmosphere, as shown. Figure 2 Such a through-hole can vertically pass through, for example, the substrate 10 and the photodeformable film 20. In some embodiments, the communication structure 1061 (1062) includes a balancing channel 10611 (10621) that communicates with the corresponding reaction channel 1041 (1042) at one end and with the atmosphere at the other end or hereinafter referred to as a trunk and branches 10613 (10623) with closed ends branching off from the trunk, as shown. Figure 3 Figure 3 The arrangement of the communication structure as shown can facilitate more accurate and stable quantification of the reaction units. Because when the sample microfluid enters the trunk to reach the intersection of the trunk with the branches, a portion of the sample microfluid will continue to move forward in the trunk while another portion will enter the branches. Since the ends of the branches are closed, the sample microfluid that enters the branches will compress the gas in the branches, which will make the sample microfluid in the trunk unable to overcome the gas pressure to move forward earlier compared to the case without branches, for example as shown. Figure 1

[0038] In some embodiments, the communication structure can be arranged outside the reaction channel. For example, with reference to Figure 1 and Figure 2 , the communication structure 1061 is arranged outside the reaction channel 1041, and the communication structure 1062 is arranged outside the reaction channel 1042. In some embodiments, the communication structure can be arranged inside the reaction channel. For example, with reference to Figure 3 , the communication structure 1061 is arranged inside the reaction channel 1041, and the communication structure 1062 is arranged inside the reaction channel 1042.

[0039] In some embodiments, for example, with reference to Figure 2 ​​In some embodiments, the microfluidic chip 100 can further include a buffer tube 107 connected between the sample inlet channel 102 and the capillary pump 103. In some embodiments, the buffer tube 107 has a cross-sectional area larger than that of the sample inlet channel 102. In some embodiments, the buffer tube 107 can include one or more connected U-shaped tubes. The provision of the buffer tube 107 can be advantageous in avoiding that the sample microfluidic is drawn by the capillary pump before the self-sealing of the communication structures 1061-1062. In other words, the provision of the buffer tube 107 can be advantageous in ensuring that the sample microfluidic is drawn by the capillary pump after the self-sealing of the communication structures 1061-1062 (i.e., the completion of the sampling process by the reaction units 110A-110B). The provision of the buffer tube 107 can also prevent the sample microfluidic from flowing back from the capillary pump 103 to the sample inlet channel 102. Alternatively, instead of the buffer tube 107, the end portion of the sample inlet channel 102 close to the capillary pump 103 can be formed as a plurality of connected bends and / or the bottom surface of the end portion of the sample inlet channel 102 close to the capillary pump 103 can be formed as a plurality of steps, which can also provide a buffer region for the sample microfluidic.

[0040] In some embodiments, the sample inlet channel 102 can be configured as a U-shaped channel, and the sample distribution channels 1051-1052 can be connected downstream of the bend segment of the U-shaped channel, which can be advantageous in maintaining the flow rate and flow volume of the sample microfluidic in the sample inlet channel 102 at a controllable range, the bend segment of the U-shaped channel can also effectively achieve the effect of buffering and liquid storage, and also reduce the footprint of the sample inlet channel 102 in the microfluidic chip 100, so that the arrangement of the sample inlet channel 102 is more reasonable.

[0041] In some embodiments, when the microfluidic chip 100 includes a plurality of reaction units, the reaction units can be located on the same side of the sample inlet channel 102 or on different sides of the sample inlet channel 102. When two reaction units are located on different sides of the sample inlet channel 102, the sample distribution channels of the two reaction units can be aligned with each other or offset from each other.

[0042] In some embodiments, pre-positioned reactants are stored at one or more different locations in one or more of the reaction channels 1041-1042, and a sample microfluid can be driven to each of the one or more different locations under the action of the Laplace pressure difference generated by the asymmetric photo-deformation of the reaction channels 1041-1042 to contact and mix and / or react with the pre-positioned reactants at that location. In some examples, these pre-positioned reactants can be added to the reaction channels 1041-1042 in advance at the manufacturing stage of the microfluidic chip 100. For example, after the grooves are made in the substrate 10, the reactants can be pre-positioned at specific locations of the grooves in the substrate 10 to be used as the reaction channels by freeze-drying, the photo-deformable film 20 is then overlaid on the substrate 10, and the substrate 10 overlaid with the photo-deformable film 20 is then packaged to obtain the microfluidic chip 100.

[0043] In some embodiments, each reaction unit can further include a flow channel configured to communicate with the mixing chamber at one end and with the reaction channel at the other end. The cross-sectional area of the mixing chamber can be greater than the cross-sectional area of the flow channel.

[0044] For example, with reference to Figure 3The reaction unit 110A further comprises a drainage channel 1091 in communication with the mixing chamber 1081 at one end and with the reaction channel 1041 at the other end, wherein the cross-sectional area of the mixing chamber 1081 is larger than that of the drainage channel 1091. The reaction unit 110B further comprises a drainage channel 1092 in communication with the mixing chamber 1082 at one end and with the reaction channel 1042 at the other end, wherein the cross-sectional area of the mixing chamber 1082 is larger than that of the drainage channel 1092. It is desirable that the sample microfluid from the sample channel 1051 (1052) first fills the mixing chamber 1081 (1082) and then enters the reaction channel 1041 (1042). However, in some cases, the sample microfluid from the sample channel 1051 (1052) can enter the reaction channel 1041 (1042) before it fills the mixing chamber 1081 (1082), which can result in the gas in the mixing chamber 1081 (1082) not being able to escape and thus forming a non-negligible bubble, which can affect the reaction process. The presence of the drainage channel 1091 (1092) in the microfluidic chip 100 can effectively alleviate or even eliminate the formation of such a bubble. Before the sample microfluid reaches the second connection point CP21 (CP22) along the reaction channel 1041 (1042) and seals the communication structure 1061 (1062), the sample microfluid will continue to move forward in the drainage channel 1091 (1092) (i.e., towards the third connection point CP31 (CP32)). After the sample microfluid reaches the second connection point CP21 (CP22) along the reaction channel 1041 (1042) and seals the communication structure 1061 (1062), the reaction channel 1041 (1042) is isolated from the atmosphere, and in order to maintain the pressure balance, the sample microfluid in the drainage channel 1091 (1092) will not move forward or backward. In addition, although the sample microfluid in the drainage channel 1091 (1092) appears to be in communication with the sample microfluid in the mixing chamber 1081 (1082), during the reaction process, the sample microfluid in the drainage channel 1091 (1092) hardly participates in the reaction, and overall, only a small amount of exchange with the sample microfluid in the mixing chamber 1081 (1082) occurs through diffusion, which is actually negligible. Similarly, the sample microfluid remaining in the sample channel 1051 (1052), the communication structure 1061 (1062) also hardly participates in the reaction, which is actually negligible.

[0045] In addition, the depth of the reaction channel 1041-1042 can be greater than the depth of the drainage channel 1091-1092. Due to the difference in depth between the drainage channel 1091-1092 and the reaction channel 1041-1042, a step can be formed at the third connection point CP31-CP32 of the drainage channel 1091-1092 and the reaction channel 1041-1042. The step at the third connection point CP31-CP32 of the drainage channel 1091-1092 and the reaction channel 1041-1042 allows the sample microfluid to be stopped in the drainage channel 1091-1092 at the third connection point CP31-CP32 of the drainage channel 1091-1092 and the reaction channel 1041-1042 under the action of surface tension even after filling the mixing chamber 1081-1082 and then filling the drainage channel 1091-1092, thereby playing a role of brake for the sample microfluid and ensuring that the reaction unit can accurately perform the quantitative sampling operation. In some embodiments, the difference between the depth of the drainage channel 1091-1092 and the depth of the reaction channel 1041-1042 can be configured to allow the microfluid to move across the third connection point CP31-CP32 of the drainage channel 1091-1092 and the reaction channel 1041-1042 in the reaction channel 1041-1042. Since the Laplace pressure difference generated by asymmetric photo-deformation can only advantageously overcome the flow resistance to drive the fluid in a straight-through pipeline with smaller flow resistance, there needs to be a significant difference between the depth of the drainage channel 1091-1092 and the depth of the reaction channel 1041-1042. If the depth of the drainage channel 1091-1092 and the depth of the reaction channel 1041-1042 are close, the pipeline shape of the reaction channel 1041-1042 at the third connection point CP31-CP32 of the drainage channel 1091-1092 and the reaction channel 1041-1042 (close to a three-way pipe) changes significantly compared to the pipeline shape of the reaction channel 1041-1042 at other parts of the reaction channel 1041-1042 (straight-through pipe), which hinders the photo-driven of the microfluid in the reaction channel 1041-1042 and makes it difficult to move freely in the reaction channel 1041-1042 from one end to the other end across the third connection point CP31-CP32. Further, in some examples, the ratio of the depth of the drainage channel 1091-1092 to the depth of the reaction channel 1041-1042 is less than 1:2. In some examples, the ratio of the depth of the drainage channel 1091-1092 to the depth of the reaction channel 1041-1042 is less than or equal to 1:4.When the ratio of the depth of the drainage channel 1091-1092 to the depth of the reaction channel 1041-1042 meets such a requirement, it can not only effectively prevent the microfluid from spontaneously entering the reaction channel 1041-1042 after the mixing chamber 1081-1082 is filled and the drainage channel 1091-1092 is filled in turn, but also reduce the influence of the third connection point CP31-CP32 of the drainage channel 1091-1092 and the reaction channel 1041-1042 on the photo-induced driving of the microfluid in the reaction channel 1041-1042.

[0046] In some embodiments, the depth of the sample splitting channel can be equal to the depth of the mixing chamber. In some embodiments, the depth of the mixing chamber can be equal to the depth of the drainage channel. In some embodiments, each reaction unit can further include a transition channel connected between the mixing chamber and the reaction channel, the depth of the transition channel varying from a first depth at a position where the transition channel is connected with the mixing chamber to a second depth at a position where the transition channel is connected with the reaction channel, the first depth being equal to the depth of the mixing chamber, and the second depth being equal to the depth of the reaction channel. For example, referring to Figure 4 The reaction unit 110A further includes transition channels 1121-1122 connected between the mixing chamber 1081 and the reaction channel 1041. The transition channels 1121-1122 provide a depth transition between the mixing chamber 1081 and the reaction channel 1041, facilitating the movement of the microfluid between the mixing chamber 1081 and the reaction channel 1041. The reaction unit 110B further includes transition channels 1123-1124 connected between the mixing chamber 1082 and the reaction channel 1042. The transition channels 1123-1124 provide a depth transition between the mixing chamber 1082 and the reaction channel 1042, facilitating the movement of the microfluid between the mixing chamber 1082 and the reaction channel 1042. For example, the bottom surface of the transition channels 1121-1124 can be formed as a flat or curved slope, or as a plurality of steps.

[0047] The dimensions of the depth and width of each channel included in the microfluidic chip 100 herein may, for example, be in the range of 10-10 3In some embodiments, the width and depth of each of the sample inlet channel 102, the sample distribution channels 1051-1052, the reaction channels 1041-1042, the communication structures 1061-1062, the mixing chambers 1081-1082, and the drain channels 1091-1092 are each between 10 micrometers and 2000 micrometers, for example, can be between 50 micrometers and 1000 micrometers. When in such a range, the microfluidic chip 100 is moderately difficult to fabricate, and the optically driven fluid performs well. In one non-limiting example, the sample inlet channel 102 can have a width of 300 micrometers and a depth of 300 micrometers, the reaction channels 1041-1042 can have a width of 200 micrometers and a depth of 200 micrometers, the mixing chambers 1081-1082 can have a width of 400 micrometers and a depth of 50 micrometers, and the sample distribution channels 1051-1052, the communication structures 1061-1062, and the drain channels 1091-1092 can have a width of 200 micrometers and a depth of 50 micrometers. From these dimensions, it can be determined that the effect of the fluid volume in the sample distribution channels 1051-1052, the communication structures 1061-1062, and the mixing chambers 1081-1082 on the accuracy of the measurement can be negligible. In some examples, the volume of the reaction channel 1041 between CP21 and CP21’ and the volume of the reaction channel 1042 between CP22 and CP22’ can be between 50 nanoliters and 1000 nanoliters, or between 100 nanoliters and 700 nanoliters. Because the volume of the reaction channel 1041 between CP21 and CP21’ and the volume of the reaction channel 1042 between CP22 and CP22’ can be small, the measurement of the sample microfluidic in such a predetermined volume can be considered as a simple and accurate trace sample quantitative measurement. However, one skilled in the art can understand that when designing the volume of the reaction channel 1041 between CP21 and CP21’ and the volume of the reaction channel 1042 between CP22 and CP22’, it can be determined according to the specific use scene of the microfluidic chip 100.

[0048] It should be understood that the different cross-sectional areas of the channels designed above can be achieved by controlling the width of the channels to be the same and changing the depth of the channels, by controlling the depth of the channels to be the same and changing the width of the channels, or by changing the depth and width of the channels at the same time. In some cases, it can be preferred to control the width of the channels to be the same and change the depth of the channels to achieve different cross-sectional areas of the channels. For example, when the channels are formed by CNC machining, it can be more convenient to control the width of the channels to be the same and change the depth of the channels.

[0049] The mixing chambers 1081-1082 can have any suitable profile, including but not limited to polygons such as triangles, quadrilaterals, pentagons, circles, ellipses, etc. For example,Figure 1 The profile of the mixing chamber 1081-1082 is shown as a quadrilateral, Figure 2 The profile of the mixing chamber 1081 is shown as a quadrilateral and the profile of the mixing chamber 1082 is shown as a circle.

[0050] In some embodiments, with reference to Figure 1 , the profile of the mixing chamber 1081 (1082) can be a quadrilateral having a first end point e 11 (e 12 ) to a fourth end point e 41 (e 42 ), the first end point e 11 (e 12 ) opposite to the fourth end point e 41 (e 42 ) and the first end point e 11 (e 12 ) adjacent to the second end point e 21 (e 22 ) and the third end point e 31 (e 32 ) respectively, wherein the mixing chamber 1081 (1082) is in communication with the dispensing channel 1051 (1052) at the first end point e 11 (e 12 ), with the reaction channel 1041 (1042) at the second end point e 21 (e 22 ) and the third end point e 31 (e 32 ), and with the drain channel 1091 (1092) at the fourth end point e 41 (e 42 ). In some examples, such a quadrilateral can be symmetrical, for example, can be axisymmetric about a longitudinal center line of the reaction channel. In some examples, such a quadrilateral can be a rhombus. Compared to the case where the mixing chamber 1081 is in communication with the dispensing channel 1051, the reaction channel 1041 and the drain channel 1091 at respective sides as shown in Figure 2 , the case where the mixing chamber 1081 is in communication with the dispensing channel 1051, the reaction channel 1041 and the drain channel 1092 at respective end points as shown in Figure 1 may be advantageous. Because the mixing chamber 1081 as shown in Figure 2 may have more “dead corners” where fluid therein is less likely to participate in mixing, resulting in lower mixing efficiency, compared to the mixing chamber 1081 as shown in Figure 1 .

[0051] During operation, photo-driven microfluidics can be used to cause the fluid in reaction channel 1041 (1042) to oscillate back and forth around mixing chamber 1081 (1082) within reaction channel 1041 (1042), thereby accelerating the mixing process. Specifically, eddies are generated at the fluid boundary inside the photo-driven fluid. When the mixing chamber 1081 (1082) is filled with fluid, the shape of the fluid boundary changes significantly when transitioning from reaction channel 1041 (1042) to mixing chamber 1081 (1082), and therefore the eddies inside the fluid change according to the change in the shape of the fluid boundary. Compared to the case where the photo-driven fluid oscillates back and forth in a straight reaction channel, adding a mixing chamber to the reaction channel can improve the mixing efficiency. Generally, when using photo-driven microfluidics to make the fluid oscillate back and forth around the mixing chamber 1081 (1082) in the reaction channel 1041 (1042), the mixing chamber 1081 (1082) is kept in a state of being filled with fluid. That is to say, during the reciprocating oscillation of the fluid, the reference... Figure 1 The lower end face of the fluid will never be higher than the third end face e. 31 (e 32 The upper surface of the fluid will never be lower than the second endpoint e. 21 (e 22 ).

[0052] In some embodiments, a barrier structure may also be provided in the mixing chamber. The barrier structure can be used to alter the shape of the fluid boundary. In some examples, the barrier structure may be located at the geometric center of the mixing chamber, and the profile of the barrier structure may conform to the profile of the mixing chamber. In some examples, the barrier structure may include at least one of the following: one or more prisms or an array of prisms; one or more cylinders or an array of cylinders; one or more baffles or an array of baffles. These barrier structures can perturb the fluid in the mixing chamber, thereby further improving the mixing efficiency of the fluid in the mixing chamber. For example, as... Figure 3 As shown, a rhomboid prism is provided at the geometric center of the rhomboid mixing chamber 1081 (1082) to serve as a barrier structure 1111 (1112), and the sides of the rhomboid prism can be parallel to the corresponding sides of the rhomboid mixing chamber. Figure 4 As shown, a cylindrical array is provided in the mixing chamber 1081 to serve as a barrier structure 1111, and a plurality of baffles are provided in the mixing chamber 1082 to serve as a barrier structure 1112. These baffles may have different orientations to further improve mixing efficiency.

[0053] In the present disclosure, the reciprocating oscillation of the fluid in the reaction channel around the mixing chamber by the way of light-induced driving of the fluid can be regarded as active mixing, and the arrangement of the mixing chamber and the barrier structure therein can be regarded as passive mixing. By the light-induced driving of the fluid technology combined with the microfluidic chip structure design, the present disclosure can realize the efficient mixing of active mixing combined with passive mixing, thereby improving the reaction efficiency in the microfluidic chip.

[0054] In addition, when the microfluidic chip 100 is formed by the substrate 10 and the light-induced deformation film 20 overlaid thereon, the arrangement of the barrier structure in the mixing chamber also has the following effects. Since the mixing chamber can be formed wide and shallow, the part of the light-induced deformation film 20 serving as the upper surface of the mixing chamber is likely to touch the bottom surface of the mixing chamber, thereby affecting the mixing of the fluid. The barrier structure arranged in the mixing chamber can act as a support for the light-induced deformation film 20 to prevent this from happening.

[0055] In some embodiments, the microfluidic chip can further include a plurality of microfluidic units independent of each other. As a non-limiting example, referring to Figure 5 , the microfluidic chip 100 includes two microfluidic units 100UA and 100UB independent of each other. Each of the microfluidic units 100UA and 100UB is not limited to the exemplary arrangement shown in Figure 5 , but can have the arrangement of the microfluidic unit according to any embodiment of the present disclosure. As shown in Figure 5 , the microfluidic unit 100UA includes a sample inlet 101A, a sample channel 102A, a capillary pump 103A, and a reaction channel 104A. The reaction channel 104A communicates with a sample distribution channel 105A and communicates with a communication structure 106A. A mixing chamber 108A is also arranged at the connection point of the reaction channel 104A and the sample distribution channel 105A. The mixing chamber 108A communicates with the sample distribution channel 105A at a first end point, communicates with the reaction channel 104A at a second end point and a third end point adjacent to the first end point via a transition channel 112A, and communicates with the reaction channel 104A at a fourth end point opposite to the first end point via a drainage channel 109A. A barrier structure 111A is arranged in the mixing chamber 108A. Further as Figure 5As shown, the microfluidic unit 100UB includes an inlet port 101B, an inlet channel 102B, a capillary pump 103B, and a reaction channel 104B. The reaction channel 104B is in communication with a distribution channel 105B and with a communication structure 106B. A mixing chamber 108B is also provided at the junction of the reaction channel 104B and the distribution channel 105B. The mixing chamber 108B is in communication with the distribution channel 105B at a first end point, with the reaction channel 104B at a second end point and a third end point adjacent to the first end point via a transition channel 112B, and with the reaction channel 104B at a fourth end point opposite to the first end point via a drainage channel 109B. An obstacle structure 111B is provided in the mixing chamber 108B. Since the microfluidic units 100UA and 100UB are independent of each other, they can be used for different sample microfluidics, respectively.

[0056] The microfluidic chip 100 provided by the present disclosure can be used for, but not limited to, PCR detection, and is particularly suitable for isothermal PCR detection. Specifically, methods such as loop-mediated isothermal amplification, nicking enzyme isothermal amplification, nucleic acid sequence-dependent amplification, rolling circle amplification, etc. all fall within the scope of isothermal PCR. Moreover, when the microfluidic chip 100 is used for isothermal PCR detection, there is no need to additionally provide a detection channel or chamber in the microfluidic chip 100, but detection can be directly performed in the mixing chamber. Not only end-point PCR detection but also real-time quantitative fluorescent PCR detection can be achieved in the microfluidic chip 100. Specifically, the temperature control component can be used to maintain the microfluidic chip at a temperature required for isothermal PCR detection. Since the reaction site is mainly located in the mixing chamber, only periodic fluorescent detection of the fluid in the mixing chamber and recording of the fluorescent intensity are required. The measured fluorescent intensity for each cycle is plotted as a curve, and the result of real-time quantitative fluorescent PCR detection can be obtained. For end-point PCR detection, only detection of the fluid in the mixing chamber after the PCR reaction is completely finished is required, and the result of end-point PCR detection can be obtained. The wavelength used for light-induced driving of the fluid is often not the same as or close to the wavelength used for fluorescent detection, so a filter can be used to exclude interference with the detection result. In addition, even if a filter is not used, or even if the wavelength used for light-induced driving of the fluid is close to the wavelength used for fluorescent detection, the impact on the detection result is small, because the light-induced driving of the fluid only requires spot-size illumination at the fluid end face to manipulate the fluid, and the fluid end face is in the reaction channel and can be actually spaced apart from the mixing chamber, so that the light-induced driving point and the fluorescent detection point of the fluid are spaced apart from each other. The microfluidic chip 100 provided by the present disclosure can also be used for biochemical detection, immunodetection, and / or molecular detection, etc.

[0057] The present disclosure also provides, in another aspect, a method for operating the aforementioned microfluidic chip.

[0058] ReferenceFigure 7 The method 200 for operating the microfluidic chip 100 can include: at step S202, adding sample microfluid to the sample inlet to cause the added sample microfluid to enter the sample channel; at step S204, after the sample microfluid self-seals the communication structure of each reaction cell and the sample microfluid still remaining in the sample channel is separated from the sample microfluid in each sample distribution channel, causing the sample microfluid in the reaction channel to move in the reaction channel by selectively locally illuminating the reaction channel.

[0059] Reference is made to Figure 8 The method 200’ for operating the microfluidic chip 100 to perform the constant-temperature PCR detection includes: at step S202’, maintaining the temperature of each reaction cell at a temperature required by the constant-temperature PCR detection; at step S204’, adding sample microfluid to the sample inlet to cause the added sample microfluid to enter the sample channel; at step S206’, after the sample microfluid self-seals the communication structure of each reaction cell and the sample microfluid still remaining in the sample channel is separated from the sample microfluid in each sample distribution channel, causing the sample microfluid in the reaction channel to reciprocally oscillate around the mixing chamber in the reaction channel by selectively locally illuminating the reaction channel.

[0060] Other embodiments of the method 200, 200’ can refer to those described above with respect to the microfluidic chip 100, which are not repeated here.

[0061] The present disclosure also provides, in yet another aspect, a microfluidic device comprising the aforementioned microfluidic chip.

[0062] Reference is made to Figure 9 A microfluidic device 300 is provided, which comprises the microfluidic chip 100 according to any of the aforementioned embodiments and a light source 310 configured to provide illumination to the microfluidic chip 100 to control the movement of microfluid in the microfluidic chip 100, especially in the reaction channel. The light source 310 can take any suitable form such as a point light source, a line light source, a surface light source, an array light source, etc., and can be any suitable light source such as a light-emitting diode (LED), a laser, etc. In some embodiments, the light source 310 can be configured to be movable relative to the microfluidic chip 100 to scan the illumination position on the microfluidic chip 100 so as to generate asymmetric photo-induced deformation along the channel, especially the reaction channel, to drive the fluid. For example, the relative movement of the light source 310 and the microfluidic chip 100 can be achieved by fixing the light source 310 while moving the microfluidic chip 100, or can be achieved by fixing the microfluidic chip 100 while moving the light source 310, or can also be achieved by moving both the light source 310 and the microfluidic chip 100 at different speeds at the same time, which is not particularly limited here. In some embodiments, for example, as shown in FIG. 3, the light source 310 is configured to be movable relative to the microfluidic chip 100 to scan the illumination position on the microfluidic chip 100 so as to generate asymmetric photo-induced deformation along the channel, especially the reaction channel, to drive the fluid. Figure 10As shown, the light source 310 can include an array of multiple light sources 310_1, 310_2, 310_3, each of which has a different illumination position on the microfluidic chip 100 (especially on the reaction channel). Thereby, switching of the illumination position can be achieved by switching of the individual light sources. Although Figure 10 Only three light sources 310_1, 310_2, 310_3 are shown in the embodiment, this is merely exemplary and not restrictive, a larger number of light sources can be arranged as needed, and they can be arranged as a one-dimensional array, a two-dimensional array, or any suitable array.

[0063] In the embodiment of Figure 9 , it can be understood that scanning of the positive light spot on the microfluidic chip 100 is provided. In some other embodiments, scanning of the negative light spot on the microfluidic chip 100 can also be provided. For example, with reference to Figure 11 , the microfluidic device 300 can further include a light shield 320 disposed between the microfluidic chip 100 and the light source 310 and configured to cause a selectable portion of the reaction channel of the microfluidic chip 100 to not receive illumination from the light source 310 while the rest receives illumination from the light source 310. The light source 310 may, for example, be configured to provide illumination to the entire microfluidic chip 100, and the projection of the light shield 320 on the microfluidic chip 100 provides a negative light spot, wherein the microfluidic chip 100 and the light source 310 can be stationary, and the light shield 320 can be movable so that different selectable portions of the reaction channel of the microfluidic chip 100 can be selected, which is equivalent to providing scanning of the negative light spot. In some other embodiments, the light shield 320 can also be configured to cause a selectable portion of the reaction channel of the microfluidic chip 100 to receive illumination from the light source 310 while the rest does not receive illumination from the light source 310. For example, the light source 310 can be configured to provide illumination to the entire microfluidic chip 100, and the light shield 320 can block all illumination except for openings therein for light leakage, in which case the microfluidic chip 100 and the light source 310 can be stationary, and the light shield 320 can be movable so that different selectable portions of the reaction channel of the microfluidic chip 100 can be selected, which is also equivalent to providing scanning of the positive light spot.

[0064] In some other embodiments, with reference to Figure 12Alternatively, the microfluidic device 300 can comprise a light attenuating sheet 330 disposed between the microfluidic chip 100 and the light source 310 and configured to cause the light source 310 light received by a selectable portion of the reaction channel of the microfluidic chip 100 to have an attenuated intensity compared to the light source 310 light received by the rest of the reaction channel. The light source 310 can be configured to provide illumination to the entire microfluidic chip 100, for example, while the projection of the light attenuating sheet 330 on the microfluidic chip 100 provides an attenuated light spot, wherein the microfluidic chip 100 and the light source 310 can be stationary, and the light attenuating sheet 330 can be movable, enabling selection of different selectable portions of the reaction channel of the microfluidic chip 100, equivalent to providing a scan of the attenuated light spot.

[0065] It can be appreciated that while the foregoing describes the light attenuating sheet 320 or the light attenuating sheet 320 moving while the light source 310 and the microfluidic chip 100 are stationary, this is merely exemplary and not limiting, and the relative motion between the above-mentioned components can be implemented in a variety of ways, as long as the scanning of the positive light spot, the negative light spot, or the attenuated light spot on the microfluidic chip 100 can be achieved.

[0066] To provide the degree of automation of the microfluidic device 300, in some embodiments, with reference to Figure 13 The microfluidic device 300 can further comprise a controller 340. The controller 340 can be configured to perform the operation method of the microfluidic chip according to any of the foregoing embodiments. For example, the controller 340 can be configured to, after the sample microfluidic self-seals the communication structure of each reaction unit of the microfluidic chip 100 and still remains in the sample channel, and the sample microfluidic in each sample channel is separated from the sample microfluidic in the respective sample channel, control the light source to move the sample microfluidic in the reaction channel by selectively locally illuminating the reaction channel. Other operation embodiments of the controller 340 can refer to those described above with respect to the microfluidic chip 100, the method 200, 200', which will not be repeated here.

[0067] The microfluidic chip and the microfluidic device according to the present disclosure effectively utilize the capillary force of the capillary pump and the Laplace pressure difference generated by the asymmetric photo-induced deformation of the channel, achieve non-contact precise driving of the microfluidic without any external driving device, and achieve precise and accurate trace sampling operation at the back end without filling the entire front channel, with low sample loss, fewer components, small overall volume, simple and robust structure, high repeatability, and high degree of portability and automation.

[0068] The present disclosure also provides, in yet another aspect, a microfluidic device for constant temperature PCR detection, which can utilize light-induced driving of microfluidics to achieve contactless driving of microfluidics in a microfluidic chip, and can also be suitable for POCT applications of constant temperature PCR detection. Microfluidic devices according to various embodiments of the present disclosure are described below with reference to the accompanying drawings. It should be understood that an actual microfluidic device can also include other components, but in order to avoid obscuring the gist of the present disclosure, these other components are not discussed herein and are not shown in the accompanying drawings.

[0069] Reference is made to Figure 14 which shows a microfluidic device 400 according to some embodiments of the present disclosure. The microfluidic device 400 includes a light control module 410, a moving module 420, a detection module 430, and a temperature control module 440, wherein the light control module 410 is fixed above the moving module 420, the detection module 430 is fixed above the moving module 420 and spaced apart from the light control module 410, and the temperature control module 440 is arranged in the moving module 420.

[0070] The light control module 410 includes a light source 411. The light source 411 is configured to provide light illumination to a microfluidic chip 460 to control the movement of microfluidics in the microfluidic chip 460. The microfluidics in the microfluidic chip 460 are light-induced drivable, which can be, for example but not limited to, the microfluidic chip 100 according to any embodiments of the present disclosure. Reference is made to Figure 16 The light emitted by the light source 411 can be totally reflected by the right-angle prism 412 onto the microfluidic chip 460. The light path design shown here is merely exemplary and not limiting, and more, fewer, or alternative optical elements can be used to design the light path from the light source 411 to the microfluidic chip 460. The light control module 410 can be similarly configured as previously mentioned with respect to the microfluidic device 300. The light source 411 can be any suitable light source such as an LED, a laser, etc. For example, the light source 411 can include multiple LEDs of different wavelengths, which can constitute a light source group capable of switching wavelengths. The light source 411 can take any suitable form such as a point light source, a line light source, a surface light source, an array light source, etc., and components for changing the form of light illumination can be provided in the light path from the light source 411 to the microfluidic chip 460. For example, in Figure 16 When the light source 411 originally provides a point light source on the microfluidic chip 460, a detachable light guide bar can be added below the right-angle prism 412 to convert the point light source into a line light source for batch light-induced driving of multiple microfluidic chips.

[0071] Reference is made to Figure 14 and Figure 16The moving module 420 is configured to move the microfluidic chip 460 to adjust the relative position of the microfluidic chip 460 and the light source 411, so that the microfluidic chip 460 is selectively and locally illuminated by the light source 411, thereby photo-driven the microfluidic fluid in the microfluidic chip 460. The moving module 420 is also configured to move the microfluidic chip 460 to adjust the relative position of the microfluidic chip 460 and the detection module 430, so that the microfluidic chip 460 is detected by the detection module 430. By staggering the detection module 430 and the light control module 410, and by moving the microfluidic chip 460 through the moving module 420, both relative movement between the microfluidic chip 460 and the light control module 410 and relative movement between the microfluidic chip 460 and the detection module 430 are achieved. This reduces the number of moving parts in the microfluidic device 400, simplifies the structure of the microfluidic device 400, and reduces manufacturing difficulty and cost.

[0072] For example, such as Figure 15 As shown, in some embodiments, the moving module 420 may include a platform 421 and a motor assembly for driving the platform 421 to move in a horizontal plane. The upper surface of the platform 421 provides a bearing surface 4211 for placing the microfluidic chip 460. It should be understood that, although Figure 14Only one microfluidic chip is shown to be placed on the bearing surface 4211, but in some embodiments, multiple microfluidic chips can also be placed on the bearing surface 4211. The motor set can include a first motor, referred to as an X-axis motor 4221, for driving the bearing table 421 to move laterally (also referred to as the X-axis direction herein) in the horizontal plane, and a second motor, referred to as a Y-axis motor 4231, for driving the bearing table 421 to move longitudinally (also referred to as the Y-axis direction herein) in the horizontal plane. The moving module 420 can further include a first guide, referred to as an X-axis guide 4222, for guiding the bearing table 421 to move laterally in the horizontal plane, and a second guide, referred to as a Y-axis guide 4232, for guiding the bearing table 421 to move longitudinally in the horizontal plane. The X-axis guide 4222 corresponds to the X-axis motor 4221, and the Y-axis guide 4232 corresponds to the Y-axis motor 4231. In some examples, each guide can include at least a set of screw-nut mechanisms and a guide rail parallel to the guiding direction, the nut in the screw-nut mechanism can be directly fixed to the bottom of the bearing table 421, and the screw is arranged along the corresponding guiding direction and connected to the output end of the corresponding motor. For example, when the X-axis motor 4221 outputs a torque, the bearing table 421 can reciprocate along the X-axis direction due to the transmission action of the screw-nut mechanism, and under the guiding action of the X-axis guide 4222, the bearing table 421 can move more stably along the X-axis direction. In addition, the X-axis motor 4221 and the X-axis guide 4222 and the Y-axis motor 4231 and the Y-axis guide 4232 work independently of each other without interfering with each other, so the bearing table 421 can move in both the X-axis direction and the Y-axis direction at the same time, so as to realize the synthesis of movement in both directions, for example, oblique or curved movement in the horizontal plane can be realized. In addition, in order to improve the control accuracy and stability, servo motors can be selected as the X-axis motor 4221 and the Y-axis motor 4231, and guide rails 4241, 4242 can also be arranged on the corresponding sides of the bearing table 421 to prevent the bearing table 421 from occurring unilateral lateral deviation. The bearing surface 4211 of the bearing table 421 can also provide a device (for example, a clamp, etc.) for fixing the microfluidic chip 460 to prevent the microfluidic chip 460 from deviating from the desired position due to sliding during the movement of the bearing table 421.

[0073] The detection module 430 is configured to perform the detection required for the constant-temperature PCR detection on the microfluidic chip 460. In some embodiments, the detection module 430 can include a fluorescence detection unit 431, an absorbance detection unit 432, and / or other types of detection units.

[0074] The temperature control module 440 (not explicitly shown in the figure as it is arranged in the moving module 420) is configured to control the temperature of the microfluidic chip 460 to be kept at a constant temperature required for the polymerase chain reaction (PCR) detection. In some embodiments, the temperature control module 440 can include an electric heater and a temperature sensor. The electric heater can be arranged in the bearing surface 4211 to transfer heat to the microfluidic chip 460 in a heat conduction manner. Of course, other heat transfer manners and other heating forms are also possible. In addition, a refrigerator or the like can also be provided according to actual needs. Since the microfluidic chip 460 is fixed on the bearing surface 4211 and the two do not displace relative to each other, the electric heater can be arranged at a position in the bearing surface 4211 corresponding to the reaction unit of the microfluidic chip 460, so as to ensure that the temperature during the reaction is controllable. The temperature sensor can take the form of a thermocouple or other form of temperature sensing component attached between the microfluidic chip 460 and the bearing surface 4211, which can monitor the temperature in the reaction unit of the microfluidic chip 460 in real time. The monitored temperature can be used to adjust the power of the electric heater to ensure that the temperature of the reaction unit of the microfluidic chip 460 is stably kept within the required range.

[0075] In some embodiments, in order to improve the temperature control accuracy of the temperature control module 440, the following process can also be performed: obtaining the volume V of the sample liquid entering the reaction unit of the microfluidic chip 460, the temperature T required for the reaction, and the type of the sample liquid; adjusting the output heating power P of the electric heater of the temperature control module 440 to the output heating power reference value P ref corresponding to the type of the sample liquid at the volume V and the temperature T; obtaining the real-time temperature T real of the sample through the temperature sensor of the temperature control module 440; and adjusting the output heating power P when the difference ΔT between the real-time temperature T real and the temperature T required for the reaction exceeds a preset value, so that the difference ΔT between the real-time temperature T real and the temperature T required for the reaction does not exceed the preset value until the reaction ends. The temperature control here can be implemented by using various suitable control methods known at present or to be opened in the future, such as a proportion integration differentiation (PID) control method. In addition, the volume V of the sample liquid entering the reaction unit of the microfluidic chip 460, the temperature T required for the reaction, and the type of the sample liquid are determined by the specific detection item, the specification and type of the microfluidic chip, that is, the above parameters are actually determined before the reaction starts, so the above information can be quickly obtained by, for example, a code scanning and recognition method. The output heating power reference value P refThe values ​​can be calculated based on the volume V of the sample liquid entering the reaction unit of the microfluidic chip 460, the required reaction temperature T, the specific heat capacity C of the sample liquid, and the density ρ. Alternatively, they can be calibrated through simulated heating experiments during the design and manufacturing process of the microfluidic chip. When in use, they can be obtained by referring to a table. When the real-time temperature T... real When the difference ΔT between the temperature required for the reaction and the temperature T exceeds the preset value, the adjustment range of the output heating power P can be determined according to the actual situation, or the reference value of the adjustment range can be determined by simulating heating experiments during the design and manufacturing process of the microfluidic chip.

[0076] Continue to refer to Figure 14 In some embodiments, the microfluidic device 400 may further include a control module 450, which communicates with the light control module 410, the detection module 430, the movement module 420, and the temperature control module 440, and is configured to control the operation of the light control module 410, the detection module 430, the movement module 420, and the temperature control module 440 to achieve microfluidic movement control, detection control, position control, and temperature control of the microfluidic chip 460. The control module 450 can perform timing control to automatically perform sample introduction, mixing, reaction, detection, and analysis on the microfluidic chip 460. For example, in... Figure 3 After the microfluidic chip 100 is fixed on the bearing surface 4211 of the carrier stage 421 of the moving module 420, the control module 450 can control the temperature control module 440 to turn on to preheat the microfluidic chip 100 to the reaction temperature. After the sample to be tested is added to the inlet 101 of the microfluidic chip 101, the sample to be tested reaches each sample dispensing channel 1051-1052 along the sample inlet channel 102 under the capillary force of the capillary pump 103, and then enters the reaction channels 1041-1042 of each reaction unit 110A-110B. At this time, the control module 450 can control the light control module 410 to turn on the light source 411 and control the moving module 420 to change the position of the microfluidic chip 100 relative to the light source 411 so that the light spot of the light source 411 moves on the reaction channels 1041-1042. The control module 450 controls the photocontrol module 410 and the movement module 420 to photo-drive the liquid in the reaction channels 1041-1042 according to the preset reaction process, so that the liquid oscillates back and forth around the mixing chambers 1081-1082 in the reaction channels 1041-1042 until the reaction is complete. During the reaction, the control module 450 controls the movement module 420 to periodically move the mixing chambers 1081-1082 of the microfluidic chip 100 into the detection field of view of the detection module 430 and controls the detection module 430 to detect them to obtain the detection results.

[0077] Continue to refer to Figure 14In some embodiments, the microfluidic device 400 can further include a housing 470, and the aforementioned control module 450, light control module 410, detection module 430, movement module 420 and temperature control module 440 can be accommodated in the housing 470. A display screen 480 and an operation panel 490 electrically coupled with the control module 450 can be arranged on the housing 470, so as to allow a user to operate the light control module 410, detection module 430, movement module 420 and temperature control module 440. Through the operation panel 490, the user can freely select and adjust the movement path of the carrying table 421, the start-stop of the light control module 410, the setting of the temperature control module 440, the selection of the detection items of the detection module 430 and the start-stop of the detection process, etc. Through the states of the movement module 420 and the light control module 410, the control module 450 can determine the position of the liquid in the microfluidic chip 460 and display it on the display screen 480. The detection results of the detection module 430 can also be displayed on the display screen 480.

[0078] The conventional PCR detection device is large in size, and the PCR reaction condition is very harsh, so the existing PCR technology is difficult to improve the reaction efficiency of PCR, shorten the reaction process, and reduce the sample dosage without affecting the detection accuracy, so it cannot be used in the POCT field. In contrast, the microfluidic device of the present disclosure can not only reduce the sample dosage, improve the reaction efficiency and shorten the reaction process by transferring the site of PCR detection into the microfluidic chip, but also has a smaller size, lower detection cost and higher detection accuracy, so it can be advantageously applied to the POCT field. The microfluidic device of the present disclosure is portable and easy to automate, simple to operate without the need for users to have professional skills, and can meet the daily detection needs of users.

[0079] The words "left," "right," "front," "back," "top," "bottom," "over," "under," "upper," "lower," and the like in the description and the claims, if any, are used for description purposes and not necessarily for describing relative positions. It is to be understood that the words so used are interchangeable under appropriate circumstances such that the embodiments of the disclosure described herein are capable of operating in other orientations than those illustrated or otherwise described herein. For example, if the device is inverted, the features described as above other features can be described as below. The device can also be oriented in other ways (rotated 90 degrees or in other orientations), and the relative spatial relationships will be interpreted accordingly.

[0080] In the description and claims, the terms "on", "attached" to, "connected" to, "coupled" to, "coupled with", or "in contact" with relate to an element in direct physical contact with the other element, or there can be one or more intermediate elements between them. In contrast, the terms "directly on", "directly attached" to, "directly connected" to, "directly coupled" to, "directly coupled with", or "directly in contact" with mean that there is no intermediate element between the elements. In the description and claims, an element arranged "adjacent" to another element can mean that the element has a portion that overlaps the adjacent element or a portion that is above or below the adjacent element.

[0081] As used herein, the word "exemplary" means "serving as an example, instance, or illustration," and not "preferred" or "advantageous over other implementations." Furthermore, the disclosure is not to be limited to any expressed or implied theory of operation by examples described herein.

[0082] As used herein, the word "substantially" means including any minor variations as a result of design, manufacturing, and / or other factors that can cause variations in the final implementation. The word "substantially" also allows for differences that are within normal manufacturing tolerances and / or other factors that can be present in an actual implementation.

[0083] In addition, the terms "first", "second", and similar terms can also be used herein, merely for purposes of reference and thus do not necessarily have to comply with the chronological or chronological order of the objects or elements they refer to. For example, unless otherwise indicated by the context, the words "first", "second", and other such numerical terms referring to a structure or an element do not imply an order or sequence.

[0084] It should also be understood that the word "comprising" or "including" when used herein is taken to specify the presence of stated features, integers, steps, operations, units and / or components but does not preclude the presence or addition of one or more other features, integers, steps, operations, units and / or components and / or groups thereof.

[0085] In the present disclosure, the term "providing" is used in a broad sense to cover all ways of obtaining an object, and thus "providing an object" includes, but is not limited to, "buying", "preparing / manufacturing", "arranging / setting", "installing / fitting", and / or "ordering" the object, etc.

[0086] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0087] Those skilled in the art will realize that the boundaries between the above described operations merely illustrative. The multiple operations can be combined into a single operation, a single operation can be distributed in additional operations and operations can be executed at least partially overlapping in time. Moreover, alternative embodiments can include multiple instances of a particular operation and the order of operations can be altered in other various embodiments. However, other modifications, variations and alternatives are also possible. The aspects and elements of all such embodiments can be combined in any manner and / or combination with one another and with other aspects or elements of other embodiments, as would be understood by one of ordinary skill in the art, to provide additional embodiments. The description and drawings are accordingly to be regarded in an illustrative rather than a restrictive sense.

[0088] While certain specific embodiments of the present disclosure have been described in detail herein, it should be understood that the examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. Embodiments disclosed herein can be combined in any manner and / or combination with one another and with other aspects or elements of other embodiments, without departing from the spirit and scope of the present disclosure. It will be appreciated by those skilled in the art that modifications, variations and alternatives to the embodiments described herein can be made without departing from the spirit and scope of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A microfluidic chip comprising a microfluidic unit, the microfluidic unit comprising: a sample inlet configured to receive a sample microfluid; a sample channel configured to communicate with the sample inlet to receive the sample microfluid from the sample inlet; a capillary pump configured to communicate with the sample channel to draw the sample microfluid through and out of the sample channel; and one or more reaction units, each reaction unit comprising: a reaction channel in a ring arrangement configured to communicate with the sample channel via a distribution channel corresponding to the reaction unit to receive a preset volume of the sample microfluid corresponding to the reaction unit from the sample channel between the sample inlet and the capillary pump, wherein the reaction channel comprises a photo-morphing material such that the microfluid is driven through the reaction channel under an asymmetric Laplace pressure difference generated by the photo-morphing material of the reaction channel, a communication structure configured to communicate with the reaction channel at one end and to maintain communication with the atmosphere at the other end, such that the sample microfluid entering the communication structure from the distribution channel via the reaction channel is able to self-seal the communication structure, wherein a first junction of the distribution channel and the reaction channel and a second junction of the reaction channel and the communication structure are spaced apart from each other along a longitudinal centerline of the reaction channel, and a mixing chamber disposed at the first junction and configured to communicate with the distribution channel and the reaction channel respectively, the microfluid in the reaction channel being mixed in the mixing chamber, wherein a cross-sectional area of the sample channel is greater than a cross-sectional area of the reaction channel, the cross-sectional area of the reaction channel is greater than a cross-sectional area of the communication structure, the cross-sectional area of the reaction channel is greater than a cross-sectional area of the mixing chamber, and the cross-sectional area of the mixing chamber is greater than a cross-sectional area of the distribution channel.

2. The microfluidic chip of claim 1, wherein, The microfluidic unit further comprises a buffer tube connected between the sample channel and the capillary pump, wherein a cross-sectional area of the buffer tube is greater than the cross-sectional area of the sample channel. 3.The microfluidic chip of claim 1, wherein: the communication structure comprises a balancing channel communicating with the corresponding reaction channel at one end and communicating with the atmosphere at the other end, a cross-sectional area of the balancing channel being smaller than the cross-sectional area of the reaction channel, wherein an end of the balancing channel is formed to be open to the atmosphere, or the end of the balancing channel comprises a balancing cavity having a vertical through-hole to communicate with the atmosphere; or the communication structure comprises a main stem communicating with the corresponding reaction channel at one end and communicating with the atmosphere at the other end, and a branch having a closed end branching from the main stem.

4. The microfluidic chip of claim 1, wherein, A width of the mixing chamber is greater than a width of the reaction channel.

5. The microfluidic chip of claim 1, wherein, The one or more reaction units are configured to receive different preset volumes of the sample microfluid from the sample channel. 6.The microfluidic chip of claim 1, wherein: the photo-morphing material is configured to swell in response to being irradiated, such that a portion of the reaction channel has a greater cross-sectional area when being irradiated than when not being irradiated, thereby driving the microfluid in the reaction channel in a direction in which an intensity of the irradiation decreases; or The photo-morphing material is configured to shrink in response to being exposed to light, such that the portion of the reaction channel has a smaller cross-sectional area when exposed to light than when not exposed to light, thereby driving the microfluid in the reaction channel towards a direction of increasing light intensity.

7. The microfluidic chip of claim 1, wherein, The photo-morphing material comprises a photo-morphing liquid crystal polymer material, the photo-morphing liquid crystal polymer material comprising a photo-responsive linear liquid crystal polymer material with a main chain of polyoctenamer and side chains containing azobenzene.

8. The microfluidic chip of claim 1, wherein, Pre-stored reactants are stored at one or more different locations in the reaction channel, and the sample microfluid can be driven to each of the one or more different locations under the Laplace pressure difference generated by the asymmetric photo-morphing of the reaction channel to contact and mix and / or react with the pre-stored reactants at the location.

9. The microfluidic chip of claim 1, wherein, Each reaction unit further comprises: a flow channel configured to communicate with the mixing chamber at one end and the reaction channel at the other end, wherein the cross-sectional area of the mixing chamber is larger than the cross-sectional area of the flow channel, and the depth of the reaction channel is larger than the depth of the flow channel.

10. The microfluidic chip of claim 9, wherein, The difference between the depth of the flow channel and the depth of the reaction channel is configured to allow the microfluid to move across the third connection point of the flow channel and the reaction channel in the reaction channel.

11. The microfluidic chip of claim 9, wherein, The ratio of the depth of the flow channel to the depth of the reaction channel is less than 1:

2.

12. The microfluidic chip of claim 9, wherein, The ratio of the depth of the flow channel to the depth of the reaction channel is less than or equal to 1:

4.

13. The microfluidic chip of claim 9, wherein, The profile of the mixing chamber is a quadrilateral, the quadrilateral having first to fourth end points, the first and fourth end points being opposite and the first end point being adjacent to the second and third end points respectively, wherein the mixing chamber communicates with the flow channel at the first end point, the reaction channel at the second and third end points, and the flow channel at the fourth end point.

14. The microfluidic chip of claim 13, wherein, The quadrilateral is a rhombus.

15. The microfluidic chip of claim 9, wherein, The depth of the mixing chamber is equal to the depth of the flow channel.

16. The microfluidic chip of claim 1, wherein, Each reaction unit further comprises: a transition channel connected between the mixing chamber and the reaction channel, the depth of the transition channel varying from a first depth at a location where the transition channel connects with the mixing chamber to a second depth at a location where the transition channel connects with the reaction channel, the first depth being equal to the depth of the mixing chamber, and the second depth being equal to the depth of the reaction channel.

17. The microfluidic chip of claim 1, wherein, An obstacle structure is provided in the mixing chamber, the obstacle structure being configured to change the fluid boundary shape.

18. The microfluidic chip of claim 17, wherein, The obstacle structure is disposed at the geometric center of the mixing chamber, and the profile of the obstacle structure is conformal to the profile of the mixing chamber.

19. The microfluidic chip of claim 17, wherein, The obstacle structure comprises at least one of: one or more prisms or an array of prisms; one or more cylinders or an array of cylinders; one or more baffles or an array of baffles.

20. The microfluidic chip according to any one of claims 1 to 19, comprising: a substrate having a sample inlet and a groove in communication with the sample inlet provided thereon; and a photo-morphing film attached to the substrate, the photo-morphing film at least partially covering the groove to form a closed channel with the groove, such that the microfluid can be driven through the closed channel under the Laplace pressure difference generated by the asymmetric photo-morphing of the closed channel, the closed channel providing at least the reaction channel.

21. The microfluidic chip of any one of claims 1 to 19, further comprising a plurality of the microfluidic units independent of each other.

22. The microfluidic chip of any one of claims 1 to 19, wherein, The microfluidic chip is used for isothermal polymerase chain reaction detection.

23. A method for operating the microfluidic chip of any one of claims 1 to 22, comprising: adding sample microfluid to the sample inlet to cause the added sample microfluid to enter the sample channel; after the sample microfluid has sealed off the communication structure of each of the one or more reaction units and is still retained in the sample channel, separating the sample microfluid in the sample channel from the sample microfluid in the respective sample splitting channel corresponding to the one or more reaction units, and causing the sample microfluid in the reaction channel to move in the reaction channel by selectively subjecting the reaction channel to light locally.

24. A method for operating the microfluidic chip of any one of claims 1 to 22 for isothermal polymerase chain reaction detection, comprising: maintaining the temperature of each of the one or more reaction units at a temperature required for isothermal polymerase chain reaction detection; adding sample microfluid to the sample inlet to cause the added sample microfluid to enter the sample channel; after the sample microfluid has sealed off the communication structure of each of the one or more reaction units and is still retained in the sample channel, separating the sample microfluid in the sample channel from the sample microfluid in the respective sample splitting channel corresponding to the one or more reaction units, and causing the sample microfluid in the reaction channel to move in the reaction channel by selectively subjecting the reaction channel to light locally.

25. A microfluidic apparatus comprising the microfluidic chip of any one of claims 1 to 22 and a light source configured to provide light to the microfluidic chip to control the movement of microfluid in the microfluidic chip.

26. The microfluidic apparatus of claim 25, wherein, the light source is configured to be movable relative to the microfluidic chip to scan the position of the light on the microfluidic chip; or the light source comprises an array of multiple light sources, each of the multiple light sources having a different position of the light on the microfluidic chip.

27. The microfluidic apparatus of claim 25, further comprising one of: a light shutter disposed between the microfluidic chip and the light source and configured to cause a selectable portion of the reaction channel of the microfluidic chip to receive the light from the light source while the rest of the reaction channel does not receive the light from the light source, or to cause a selectable portion of the reaction channel of the microfluidic chip to not receive the light from the light source while the rest of the reaction channel receives the light from the light source; or a light attenuator disposed between the microfluidic chip and the light source and configured to cause a selectable portion of the reaction channel of the microfluidic chip to receive the light from the light source with an attenuated intensity compared to the light received by the rest of the reaction channel.

28. The microfluidic apparatus of claim 27, wherein, the microfluidic chip and the light source are stationary, and the light shutter or the light attenuator is movable, enabling selection of different selectable portions of the reaction channel of the microfluidic chip.

29. The microfluidic device of claim 25, further comprising a controller configured to: after the sample microfluidic self-seals the communication structure of each of the one or more reaction units and remains in the sample loading channel separate from the sample microfluidic in the respective sample splitting channel corresponding to the one or more reaction units, the controller controls the light source to move the sample microfluidic in the reaction channel by selectively locally illuminating the reaction channel.

30. A microfluidic apparatus for isothermal polymerase chain reaction detection, comprising: a light control module comprising a light source configured to provide illumination to a microfluidic chip to control movement of microfluidic in the microfluidic chip, the microfluidic in the microfluidic chip being optically actuable; a detection module configured to perform detection required for isothermal polymerase chain reaction detection on the microfluidic chip; a movement module configured to move the microfluidic chip to adjust relative position of the microfluidic chip to the light source such that the microfluidic chip is selectively locally illuminated by the light source to cause the microfluidic in the microfluidic chip to be optically actuated, and to move the microfluidic chip to adjust relative position of the microfluidic chip to the detection module such that the microfluidic chip is detected by the detection module; a temperature control module configured to control temperature of the microfluidic chip to be maintained at a temperature required for isothermal polymerase chain reaction detection, wherein the light control module is fixed above the movement module, the detection module is fixed above the movement module and spaced apart from the light control module, and the temperature control module is arranged in the movement module, wherein the microfluidic chip is according to any one of claims 1 to 22.

31. The microfluidic apparatus of claim 30, further comprising: a control module in communication with the light control module, the detection module, the movement module and the temperature control module respectively, and configured to control operation of the light control module, the detection module, the movement module and the temperature control module to achieve microfluidic movement control, detection control, position control and temperature control of the microfluidic chip.

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