Patent Publication Number: US-2021170407-A1

Title: Microfluidic chip and detection method thereof, micro total analysis system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the priority of the Chinese Patent Application No. 201910403124.7 filed on May 15, 2019, the content of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the technical field of immunodetection, in particular to a microfluidic chip and a detection method thereof, and a micro total analysis system. 
     BACKGROUND 
     Microfluidic chip technology is a technology that a plurality of units for basic operations such as preparation, transportation, reaction, separation, detection for biological or chemical sample are integrated on one chip, and has been rapidly developed in the fields of medicine, chemistry, material science, life science and the like due to its unique advantages such as little biological sample consumption, high analysis speed, low cost, easy miniaturization, integration, portability and the like. 
     SUMMARY 
     The present disclosure provides a microfluidic chip and a detection method thereof, and a micro total analysis system. 
     The present disclosure provides a microfluidic chip, including: a support, an near field communication (NFC) coil and a flow path in the support, and the flow path is isolated from the NFC coil; the flow path includes at least one detection window region with a stationary phase therein, and the detection window region at least partially overlaps with the NFC coil in a thickness direction of the support, to change a value of at least one radiation parameter of the NFC coil when the stationary phase specifically captures a target analyte. 
     In some implementations, the flow path includes a plurality of detection window regions, different detection window regions have different stationary phases therein; and when materials with a same dielectric constant are filled in any two detection window regions at different times, radiation parameters of the NFC coil are different. 
     In some implementations, a portion of the NFC coil that overlaps with each detection window region is a single line segment, and lengths of line segments corresponding to different detection window regions are different. 
     In some implementations, the flow path includes a plurality of detection window regions, different detection window regions have different stationary phases therein; and when materials with a same dielectric constant are filled in any two detection window regions at different times, radiation parameters of the NFC coil are the same. 
     In some implementations, the support includes: a substrate, an insulating layer on the substrate and a cover on the insulating layer, where a groove is provided in the insulating layer at a side proximal to the cover, and the cover and the groove enclose the flow path. 
     In some implementations, the support includes: a substrate, an insulating layer on the substrate and a cover on the insulating layer, where a groove is provided in the cover at a side proximal to the insulating layer, and the groove and the insulating layer enclose the flow path. 
     In some implementations, the NFC coil is a planar metal coil wound on the substrate, and the insulating layer covers the NFC coil to isolate the NFC coil from the flow path; and the NFC coil includes a plurality of first wires extending along a first direction and a plurality of second wires extending along a second direction, wherein the first direction and the second direction intersect with each other. 
     In some implementations, a distance between the flow path and the NFC coil is not greater than 300 nm. 
     In some implementations, the flow path includes a plurality of detection window regions, and the plurality of detection window regions are respectively overlapped with a plurality of portions with different lengths of a same one of the first wires or a same one of the second wires. 
     In some implementations, the flow path includes a plurality of detection window regions, and the plurality of detection window regions are respectively overlapped with a plurality of portions with a same length of a same one of the first wires or a same one of the second wires, and distances between the plurality of detection window regions and a center of the NFC coil are different. 
     In some implementations, a width of the flow path is in a range of 20 μm to 400 μm. In some implementations, the insulating layer is made of photoresist, and the substrate and the cover are made of glass. 
     In some implementations, a hydrophilic layer is provided on an inner wall of the flow path, and the hydrophilic layer may be a silicon dioxide layer. 
     In some implementations, a hydrogel is provided in the detection window region, and the stationary phase is pre-modified in the hydrogel. 
     In some implementations, the hydrogel includes a deoxyribonucleic acid (DNA) hydrogel or a polyethylene glycol (PEG) hydrogel. 
     Accordingly, the present disclosure further provides a micro total analysis system, including: the above microfluidic chip and an NFC reading device configured to obtain a magnitude of the radiation parameter of the NFC coil in the microfluidic chip. 
     Accordingly, the present disclosure further provides a detection method of the above microfluidic chip, including steps of: 
     driving liquid to be detected to flow along the flow path of the microfluidic chip; 
     obtaining the magnitude of the at least one radiation parameter of the NFC coil; 
     determining a detection result according to the magnitude of the at least one radiation parameter; where the detection result includes: whether various objects to be detected in the liquid to be detected contain the target analyte capable of being specifically captured by the stationary phases, and the target analyte is marked with modifiers capable of changing the at least one radiation parameter of the NFC coil. 
     In some implementations, the step of determining the detection result according to the magnitude of the radiation parameter includes: 
     determining the detection result corresponding to the obtained magnitude of the radiation parameter according to a preset mapping relationship, where the mapping relationship includes a corresponding relationship between a plurality of value ranges of the radiation parameter and respective corresponding detection results. 
     In some implementations, the modifier includes any one of nano-gold, nano-ferroferric tetrachloride and nano-ceramic. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification, and are used to interpret the present disclosure together with the following specific embodiments, but do not constitute a limitation to the present disclosure. In the drawings: 
         FIG. 1  is a top view of a microfluidic chip according to an embodiment of the present disclosure; 
         FIG. 2  is a top view of a microfluidic chip according to an embodiment of the present disclosure; 
         FIG. 3  is a cross-sectional view taken along AA line of  FIG. 2 ; 
         FIG. 4  is a schematic cross-sectional view of a detection window region; 
         FIG. 5  is a flow chart of a detection method of a microfluidic chip according to the present disclosure; 
         FIG. 6  is a schematic view of a target analyte captured by the detection window region; and 
         FIG. 7  is a schematic diagram of a micro total analysis system according to the present disclosure. 
     
    
    
     DETAIL DESCRIPTION OF EMBODIMENTS 
     The specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely used to illustrate and explain the present disclosure, and are not used to limit the present disclosure. 
     When the microfluidic chip in the related art detects a sample, it needs devices such as a scanner, a color development processing device to output a detection result, and thus the time for detecting the sample is prolonged. 
       FIG. 1  is a top view of a microfluidic chip according to an embodiment of the present disclosure,  FIG. 2  is a top view of a microfluidic chip according to an embodiment of the present disclosure, and  FIG. 3  is a cross-sectional view taken along AA line in  FIG. 2 . As shown in  FIGS. 1 to 3 , the microfluidic chip includes: a support  10  and an NFC (Near Field Communication) coil  20  provided in the support  10 . A flow path  11  is provided in the support  10 , and is isolated from the NFC coil  20 , for example by an insulating layer  13  as shown in  FIG. 3 . The layer for the isolation is as thin as possible, for example, the thickness of the layer for the isolation is not greater than 300 nm. The flow path  11  includes at least one detection window region  11   a  in which a stationary phase is provided, and the stationary phase is used for specifically capturing a target analyte, and each detection window region  11   a  at least partially overlaps with one trace of the NFC coil  20  in a thickness direction of the support  10 . That is, the present disclosure applies the near field communication technology to the microfluidic chip, and detects a biological sample by using a non-contact identification technology of the near field communication. 
     As shown in  FIG. 3 , the flow path  11  covers only one trace of the NFC coil  20  in a width direction to avoid affecting traces in other areas. A width of the flow path  11  is typically set between 20 μm and 400 μm based on a trace width of the NFC coil  20 . 
     The stationary phase may be an antigen/antibody. The microfluidic chip may be used in immunodetection, and particularly is used for detecting whether a liquid contains a target analyte, where the target analyte is an antibody/antigen capable of specifically binding to the stationary phase. For example, if the stationary phase is a hepatitis B antibody, the target analyte is a hepatitis B antigen capable of specifically binding to the hepatitis B antibody. The target analyte is captured by specific interaction with the stationary phase. 
     The NFC coil  20  is a coil in near field communication, and the coil is a planar metal coil formed by winding layer by layer and from inside to outside (or from outside to inside), and may be wound into a rectangular shape, a circular shape, or other shapes. As shown in  FIGS. 1 to 3 , the metal coil  20  may be wound on a substrate  12 , and two ends of the coil are connected to an NFC peripheral chip, for performing the near field communication in cooperation with an NFC reading device. When the NFC coil  20  approaches the NFC reading device, the NFC reading device sends an electromagnetic wave signal to the NFC coil  20 , and determines a magnitude of a radiation parameter (e.g., a center frequency, a port parameter, a resonance frequency, etc.) of the NFC coil  20  according to the electromagnetic wave signal reflected by the NFC coil  20 . 
     When the microfluidic chip of the present embodiment is used for immunodetection, a modifier (for example, nano-gold, nano-ceramic, etc.) may be marked on various objects to be detected in the liquid to be detected. In this way, after the stationary phase in the detection window region captures the target analyte, due to the presence of the modifier, an electromagnetic property (mainly, dielectric constant) of the detection window region may be changed, and thus the magnitude of the radiation parameter of the NFC coil  20  is changed. At this time, as long as the radiation parameter of the NFC coil  20  is read by the NFC reading device, it may be quickly determined whether the stationary phase has captured the target analyte, that is, whether the target analyte capable of being captured by the stationary phase exists in the liquid to be detected. Therefore, the microfluidic chip in the embodiment may obtain the detection result conveniently and instantly by using the near field communication technology. 
     As shown in  FIG. 3 , the support  10  includes: the substrate  12 , the insulating layer  13  and a cover  14  provided on the substrate  12 , where the cover  14  is provided on a side of the insulating layer  13  distal to the substrate  12 , a groove is provided in the insulating layer  13 , and the flow path  11  is surrounded (enclosed) by the cover  14  and the groove. A hydrophilic layer is provided on an inner wall of the flow path  11 . 
     Both the substrate  12  and the cover  14  may be glass substrates, and the insulating layer  13  may be made of photoresist. The groove is formed by exposing and developing the photoresist. The hydrophilic layer may be specifically a modified layer of a SiO 2  layer, which may be formed by sputtering. Certainly, the groove forming the flow path  11  may be formed in a surface of the cover  14  proximal to the substrate  12 . 
       FIG. 4  is a schematic cross-sectional view of a detection window region of the flow path  11 . As shown in  FIG. 4 , the detection window region  11   a  is provided with a hydrogel  30 , and the stationary phase  40  is previously modified in the hydrogel  30 . By providing the hydrogel  30 , more stationary phases  40  may be modified in the detection window region, thereby capturing more target analytes and further improving the detection accuracy. 
     The hydrogel  30  includes a DNA hydrogel or a PEG hydrogel. 
     As shown in  FIG. 1 , there is one detection window region  11   a ; alternatively, as shown in  FIG. 2 , there are a plurality of detection window regions  11   a . In the case that the number of the detection window region  11   a  is one, when the liquid to be detected contains the target analyte corresponding to the stationary phase, and the target analyte is captured, the magnitude of the radiation parameter of the NFC coil  20  changes. At this time, it is determined that the liquid to be detected contains the target analyte corresponding to the stationary phase according to the change of the magnitude of the radiation parameter. 
     In the case where the flow path  11  includes the plurality of detection window regions  11   a , different stationary phases are provided in different detection window regions  11   a . It will be appreciated that each stationary phase specifically captures the respective target analyte, i.e., different stationary phases are used to capture different target analytes, thereby allowing for identification of the different target analytes. 
     It should be noted that a type of material in the detection window region  11   a , physical parameters of the detection window region  11   a  (for example, a length of a wire of the NFC coil  20  in the detection window region  11   a , a distance from the detection window region  11   a  to a center of the NFC coil  20 , etc.) all affect a value of the radiation parameter of the NFC coil  20 . Therefore, in order to determine whether all the objects to be detected in the liquid to be detected include the target analyte corresponding to the stationary phase  40  in each detection window region  11   a , when the physical parameters of the detection window regions  11   a  are the same, modifiers for marking different objects to be detected are different; when the physical parameters of the detection window regions are different, modifiers for marking different objects to be detected may be the same or different; thereby ensuring that values of the radiation parameter of the NFC coil  20  are different when different detection window regions  11   a  capture the target analyte by saturation at different times respectively. 
     In some implementations, the plurality of detection window regions  11   a  are provided in a manner such that: when materials having a same dielectric constant are filled (captured) in any two detection window regions  11   a  at different times, radiation parameters of the NFC coil  20  are different. That is, physical parameters of the plurality of detection window regions  11   a  are different. 
     Specifically, as shown in  FIG. 2 , a portion of the NFC coil  20  overlapping each detection window region  11   a  is a single line segment, and lengths of line segments corresponding to different detection window regions  11   a  are different. Further, the NFC coil  20  includes a plurality of first wires  21  extending in a first direction X and a plurality of second wires  22  extending in a second direction Y, and the first direction and the second direction intersect with each other; the plurality of detection window regions  11   a  overlap different portions of a same one of the first wires  21 , resulting in overlapping regions have different lengths. 
     Certainly, the lengths of the line segments corresponding to different detection window regions  11   a  may be the same, and distances from the different detection window regions  11   a  to the center of the NFC coil  20  may be different. 
     In other implementations, the plurality of detection window regions  11   a  are provided in a manner such that: when the materials having a same dielectric constant are filled (captured) in any two detection window regions  11   a  at different times, the radiation parameters of the NFC coil  20  are the same. That is, the physical parameters of the plurality of detection window regions  11   a  are the same. 
     Specifically, the portion of the NFC coil  20  that overlaps with each detection window region  11   a  is a single line segment, and the lengths of the line segments corresponding to different detection window regions  11   a  are different. However, the present disclosure is not limited thereto. The line segment of the NFC coil  20  corresponding to each detection window region  11   a  may be a plurality of discontinuous line segments, and may even include corners of the trace of the NFC coil  20 . Such an arrangement including the corners of the trace may lose a linearity of some data, which may be overcome by knowing the length of the line segment corresponding to measured values of each detection window region  11   a . However, in consideration of the filling of the hydrogel  30  in the flow path  11 , the trace corresponding to each detection window region  11   a  is typically provided as a single line segment. 
       FIG. 5  is a flowchart of a detection method of the microfluidic chip provided by the present disclosure, and as shown in  FIG. 5 , the detection method includes following steps S 1  to S 3 . 
     S 1 , driving the liquid to be detected to flow along the flow path of the microfluidic chip, where the liquid to be detected contains at least one object to be detected marked with the modifier. 
     The method for driving the liquid to be detected is not particularly limited in the present disclosure, and for example, the liquid is driven to flow by a mechanical driving or an electrophoresis/electroosmosis manner. 
     The object to be detected is marked with the modifier for changing the dielectric constant of a medium in the flow path when the object to be detected is captured. The modifier includes any one of nano-gold, nano-ferroferric tetrachloride and nano-ceramic. 
       FIG. 6  is a schematic view of the target analyte captured by the detection window region. As shown in  FIG. 6 , when the liquid to be detected flows along the flow path, the stationary phase  40  in the detection window region  11   a  is specifically bonded to the corresponding target analyte  60 , so that the target analyte  60  is captured, and the rest of objects to be detected continue to flow forward without being captured. Since the target analyte  60  is marked with the modifier  50 , when the target analyte  60  is captured by the detection window region  11   a , the dielectric constant of the detection window region  11   a  changes, so that the magnitude of the radiation parameter of the NFC coil changes. 
     S 2 , obtaining the magnitude of the radiation parameter of the NFC coil. 
     As described above, the radiation parameter may be a center frequency, a port parameter, a resonance frequency, and the like. The magnitude of the radiation parameter may be obtained by using the NFC reading device. 
     S 3 , determining a detection result according to the magnitude of the radiation parameter; the detection result includes: whether or not the objects to be detected in the liquid to be detected contain the target analyte capable of being specifically captured by the stationary phase. 
     The step S 3  specifically includes: determining the detection result corresponding to the obtained magnitude of the radiation parameter according to a preset mapping relationship, where the mapping relationship includes a corresponding relationship between a plurality of value ranges of the radiation parameter and respective corresponding detection results. The mapping relationship may be obtained in advance through an experimental manner. 
     For example, when the flow path includes one detection window region, as shown in  FIG. 1 , a stationary phase A is provided in the detection window region. In this case, a modifier X is marked on a target analyte A 1  capable of specifically binding to the stationary phase A, and a liquid sample including the target analyte A 1  is introduced into the flow path, so that the target analyte A 1  marked with the modifier X is captured by saturation in the detection window region. At this time, the value of the radiation parameter of the NFC coil is detected, and a first value range fluctuating around the value is determined; values in the first value range correspond to the detection result of “the liquid to be detected contains the target analyte A 1 ”; the other values outside the first value range correspond to the detection result of “the liquid to be detected does not contain the target analyte A 1 ”. When the microfluidic chip is used for immunodetection, the modifier X is marked in the object to be detected of the liquid to be detected, the liquid to be detected is driven to flow along the flow path. If it is detected that the value of the radiation parameter of the NFC coil is in the first value range, it is determined that the liquid to be detected contains the target analyte A 1 , and if it is detected that the value of the radiation parameter of the NFC coil is not in the first value range, it is determined that the liquid to be detected does not contain the target analyte A 1 . 
     For example, when the flow path includes three detection window regions, as shown in  FIG. 2 , the three detection window regions are respectively provided with a stationary phase A, a stationary phase B, and a stationary phase C; a portion of the NFC coil  20  overlapping each detection window region is a single line segment, and the lengths of the line segments corresponding to different detection window regions are different. In this case, modifiers X are marked on a target analyte A 1  capable of specifically binding to the stationary phase A, on a target analyte B 1  capable of specifically binding to the stationary phase B, and on a target analyte C 1  capable of specifically binding to the stationary phase C; then, a plurality of liquid samples (for example, the target analytes contained in the plurality of liquid samples are respectively: A 1 , B 1 , C 1 , A 1 +B 1 , A 1 +C 1 , B 1 +C 1 , and A 1 +B 1 +C 1 ) containing incompletely same types of target analytes are introduced into the flow path, respectively, the value of the radiation parameter corresponding to each liquid sample is detected, and the value range of the radiation parameter corresponding to each liquid sample is determined. When the microfluidic chip is used for immunodetection, the modifier X is marked on each object to be detected in the liquid to be detected, the liquid to be detected is driven to flow along the flow path, and the type of the target analyte in the liquid to be detected is determined according to the value of the radiation parameter of the NFC coil and the value range of the radiation parameter corresponding to each liquid sample. 
     As described above, the plurality of detection window regions may be provided according to the following conditions: when materials with a same dielectric constant are captured in any two detection window regions at different times, the radiation parameters of the NFC coil are the same. In this case, the modifiers marked on different types of objects to be detected in the liquid to be detected are different, so that the radiation parameters of the NFC coil are different when the types of the target analytes in the liquid to be detected are different. 
     For example, when the flow path includes two detection window regions, the two detection window regions are respectively provided with a stationary phase A and a stationary phase B, the stationary phase A may specifically bind to a target analyte A 1 , and a modifier A 2  is marked on the target analyte A 1 ; the stationary phase B may specifically bind to a target analyte B 1 , and a modifier B 2  is marked on the target analyte B 1 ; the portion of the NFC coil  20  overlapping each detection window region is a single line segment, and the lengths of the line segments corresponding to different detection window regions are the same. In this case, before performing the detection, the modifier A 2  is marked on the target analyte A 1  and the modifier B 2  is marked on the target analyte B 1 ; then, a first liquid sample containing the target analyte A 1 , a second liquid sample containing the target analyte B 1 , and a third liquid sample containing the target analytes A 1 +B 1  are respectively introduced into the flow path, and a value of the radiation parameter corresponding to each liquid sample is detected, so that a value range of the radiation parameter corresponding to each liquid sample is determined. When the microfluidic chip is used for immunodetection, the modifier A 2 , the modifier B 2 , the modifier A 2 +the modifier B 2  are respectively marked in the liquid to be detected; and whether the liquid to be detected contains the target analyte A 1 /the target analyte B 1  or not is determined according to values of the radiation parameter corresponding to the liquid to be detected marked with the three modifiers and value ranges of the radiation parameter corresponding to the three liquid samples. 
     The present disclosure further provides a micro total analysis system, as shown in  FIG. 7 , which includes an NFC reading device  100  and the above microfluidic chip, where the NFC reading device  100  is configured to obtain a magnitude of a radiation parameter of an NFC coil in the microfluidic chip. 
     Specifically, the NFC reading device is used for sending an electromagnetic wave signal to the NFC coil when the NFC reading device is relatively near the microfluidic chip, and the magnitude of the radiation parameter of the NFC coil is determined according to the electromagnetic wave signal reflected by the NFC coil. 
     The NFC reading device  100  may be a smart device such as a mobile phone or a reader having an NFC response module. 
     It will be understood that the above embodiments are merely exemplary embodiments employed to illustrate principles of the present disclosure, and the present disclosure is not limited thereto. It will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the present disclosure, and these changes and modifications are to be considered within the scope of the present disclosure.