A microfluidic chip and a method for reducing mutual interference between adjacent channels of the microfluidic chip

Abstract

The application discloses a micro-fluidic chip and a method for reducing mutual interference of adjacent channels of the micro-fluidic chip, and the micro-fluidic chip comprises a plurality of micro-fluidic channels and a single positioning channel; the single positioning channel is located at the right side of the plurality of micro-fluidic channels, and the single positioning channel is parallel to each micro-fluidic channel. The application optimizes the structure of the micro-fluidic chip, sets the single positioning channel parallel to each micro-fluidic channel on the micro-fluidic chip, and uses the single positioning channel to judge the size of a focused light spot of a laser source on the micro-fluidic chip; an optical detection circuit is built to detect the diffraction light intensity of the laser passing through the micro-fluidic chip; and an automatic sample control platform is built to control the movement of the laser source, thereby controlling the size and position of the focused light spot on the micro-fluidic chip. The application adjusts the size of the laser light spot on the channel, reduces the scattering light intensity of the laser on the adjacent channels, and achieves the purpose of inhibiting the interference of the adjacent channels.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biological detection technology, in particular to a microfluidic chip and a method for reducing mutual interference between adjacent channels of the microfluidic chip. BACKGROUND

[0002] The principle of digital PCR is to let the droplets pass through the microfluidic channels on the microfluidic chip, as shown in FIG. 1, a laser light source is arranged on the microfluidic channel, and the light source is a focused light source. The droplets in the microfluidic channel are irradiated by the light source, so that the probes in the droplets emit fluorescence, and then the fluorescence is collected. Figure 1

[0003] Digital PCR has high sensitivity to signals, and the microfluidic channels on the chip are arranged densely at the fluorescence reading position. The observation channel diameter is 10 um, the channel spacing is 100 um-200 um, and the chip material has high transparency.

[0004] When the distance between the microfluidic channel array and the laser changes, the size of the focused light spot changes. As shown in FIG. 2, the distances between the three microchannel arrays and the laser are from far to near, and different sizes of focused light spots are generated. Since the microfluidic channels are densely arranged, the focused light spot of the excitation light source needs to have high requirements. First, the focused light spot needs to be small enough, with a diameter of about 10 um, which is equal to the diameter of the observation channel, and second, the center of the focused light spot needs to be positioned completely on the observation channel. Figure 2

[0005] However, the initial physical structure of the focused light spot changes with the aging of the device and the abnormal change of the relative position. Since the initial position is the best focused light spot position, the change of the light spot on the observation channel makes the diameter of the focused light spot on the observation channel larger. When the focused light spot changes, even if the focused light spot can be positioned at the center of the observation channel, due to the increase in the size of the light spot, the laser will irradiate the adjacent channel. If there is a residual droplet of the previous sample on the adjacent channel, the corresponding fluorescence will be excited, which will interfere with the fluorescence collection of the droplet on the current channel, and the following effects will be caused.

[0006] 1. The fluorescence noise of the current channel increases, making it difficult to read the data of the droplet in the current channel.

[0007] 2. Since the residual droplet is not driven and is in a free state, it will generate many invalid droplets that cannot be filtered out by normal droplet screening, thereby affecting the interpretation of the overall sample data. SUMMARY

[0008] ​​The application aims to provide a micro-fluidic chip and a method for reducing mutual interference of adjacent channels of the micro-fluidic chip.

[0009] The technical scheme of the application is:

[0010] The micro-fluidic chip comprises a plurality of micro-fluidic channels and a single positioning channel.

[0011] Preferably, the micro-fluidic channel adopts a structure of narrow in the middle and wide on both sides, and the narrow part in the middle is the fluorescence observation position.

[0012] Preferably, the width of the single positioning channel is 1.3-2 times the width of the fluorescence observation position of the micro-fluidic channel.

[0013] The method for reducing mutual interference of adjacent channels of the micro-fluidic chip comprises the following steps:

[0014] S1. Optimizing the structure of the micro-fluidic chip, and setting a single positioning channel parallel to each micro-fluidic channel on the micro-fluidic chip, which is used for judging the size of the focused light spot of the laser source on the micro-fluidic chip;

[0015] S2. Building an optical detection circuit to detect the diffraction light intensity of the laser passing through the micro-fluidic chip;

[0016] S3. Building an automatic sample control platform to control the movement of the laser source, and thus control the size and position of the focused light spot on the micro-fluidic chip.

[0017] Preferably, in S1, the single positioning channel is parallel to each micro-fluidic channel of the micro-fluidic chip, and the width of the single positioning channel is 1.5 times the width of the fluorescence observation position of the micro-fluidic channel.

[0018] Preferably, in S2, the optical detection circuit comprises a photoelectric conversion module and a high-speed analog-digital conversion acquisition circuit connected thereto, the photoelectric conversion module and the laser source are located on opposite sides of the micro-fluidic chip, the laser is diffracted when passing through the micro-fluidic chip, and the photoelectric conversion module acquires the diffraction light intensity.

[0019] Preferably, the method for controlling the movement of the laser source in S3 comprises:

[0020] S3-1. Establishing a three-dimensional coordinate system of X, Y and Z, the X axis is perpendicular to the micro-fluidic chip, the Y axis is parallel to the micro-fluidic chip and perpendicular to each micro-fluidic channel, and the Z axis is parallel to the micro-fluidic chip and parallel to each micro-fluidic channel;

[0021] S3-2, fix the initial position of the laser source: position in X direction to the position where the laser spot irradiated on the chip is consistent with the microfluidic channel; position in Y direction to the left of the individual positioning channel, and position in Z direction to the range between the two ends of the individual positioning channel;

[0022] S3-3, move the laser source in X direction away from and close to the chip, and each time the laser source moves in X direction, move it in Y direction at a constant speed to make the laser pass through the individual positioning channel, and record and analyze the photoelectric conversion data to determine the size of the laser spot on the microfluidic channel;

[0023] S3-4, according to the size of the laser spot on the microfluidic channel analyzed in S3-3, select the final appropriate position of the laser source.

[0024] Preferably, in S3-3, the photoelectric conversion data includes the waveform width and amplitude of the fluorescence intensity.

[0025] The advantages of the present application are:

[0026] 1. The present application optimizes the structure of the microfluidic chip, and forms an automatic X-axis position determination by judging the size of the laser spot on the channel.

[0027] 2. The present application reduces the scattering light intensity of the laser on the adjacent channel by adjusting the size of the laser spot on the channel, and achieves the purpose of suppressing the interference of the adjacent channel. BRIEF DESCRIPTION OF DRAWINGS

[0028] The present application will be further described below in conjunction with the drawings and examples:

[0029] Figure 1 is a schematic diagram of the laser source and the microfluidic chip in the prior art;

[0030] Figure 2 is a schematic diagram of the laser source in the prior art producing a focused spot on the microfluidic channel of the microfluidic chip at different distances;

[0031] Figure 3 is a schematic diagram of the structure of the microfluidic chip of the present application;

[0032] Figure 4 is a positioning schematic diagram of the photoelectric conversion module of the optical detection circuit and the individual positioning channel of the present application;

[0033] Figure 5 is a schematic diagram of the fixed initial position of the laser head of the present application;

[0034] Figure 6 is a schematic diagram of the change of fluorescence intensity during the process of finding the individual positioning channel;

[0035] Figure 7Fig. 2 is a graph showing the change in fluorescence intensity during the process of confirming the focusing position;

[0036] Figure 8 Fig. 3 is a graph showing the change in fluorescence intensity and the change in waveform width during the process of confirming the focusing position. Embodiments

[0037] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0038] It is to be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. 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. The terms comprising, including, containing and having are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps can be employed.

[0039] Although the terms first, second, third, and the like can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to differentiate one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second", and the like are used herein to describe a variety of elements, components, regions, layers and / or sections. Therefore, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

[0040] Spatially relative terms, such as "inner", "outer", "beneath", "below", "lower", "above", "upper", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. Embodiments

[0041] As Figure 3As shown, the microfluidic chip of the present application comprises a plurality of microfluidic channels and a single positioning channel; the single positioning channel is located on the right side of the plurality of microfluidic channels, and the single positioning channel is parallel to each microfluidic channel. The microfluidic channel adopts a structure of narrow in the middle and wide on both sides, and the narrow part in the middle is the fluorescence observation position. The width of the narrow part in the middle is 10 um, the width of the wide part on both sides is 20 um, and the interval between each microfluidic channel is 100 um. The width of the single positioning channel is 1.3-2 times the width of the fluorescence observation position of the microfluidic channel, and in this embodiment, it is 1.5 times, that is, 15 um. Embodiment

[0042] The method for reducing the mutual interference of adjacent channels of the microfluidic chip of the present application comprises:

[0043] S1, optimizing the structure of the microfluidic chip, such as Figure 3 As shown, a single positioning channel parallel to each microfluidic channel is arranged on the microfluidic chip, which is used to judge the size of the focused light spot of the laser source on the microfluidic chip; the single positioning channel is parallel to each microfluidic channel of the microfluidic chip, and the width of the single positioning channel is 1.5 times the width of the fluorescence observation position of the microfluidic channel.

[0044] S2, building an optical detection circuit to detect the diffraction light intensity of the laser passing through the microfluidic chip; as Figure 4 As shown, the optical detection circuit comprises a photoelectric conversion module and a high-speed analog-digital conversion acquisition circuit connected thereto, and the photoelectric conversion module and the laser source are located on opposite sides of the microfluidic chip. The laser is diffracted when passing through the microfluidic chip, and the photoelectric conversion module acquires the diffraction light intensity.

[0045] S3, building an automatic sample loading control platform to control the movement of the laser source, and thus control the size and position of the focused light spot on the microfluidic chip.

[0046] The method for controlling the movement of the laser source in S3 comprises:

[0047] S3-1, establishing a three-dimensional coordinate system of X, Y and Z, the X axis is perpendicular to the microfluidic chip, the Y axis is parallel to the microfluidic chip and perpendicular to each microfluidic channel, and the Z axis is parallel to the microfluidic chip and parallel to each microfluidic channel;

[0048] S3-2, fixing the initial position of the laser source: as Figure 5 As shown, the X direction is positioned to the position where the laser spot irradiated on the chip is consistent with the microfluidic channel; the Y direction is positioned to the left of the single positioning channel, and the Z direction is positioned to the range between the two ends of the single positioning channel;

[0049] S3-3, writing the software related control logic of the automatic sample loading control platform to find the single positioning channel and confirm the focusing position:

[0050] The laser source moves from near to far to the chip in the X direction, and each time the X direction moves, the laser passes through the single positioning channel at a uniform speed in the Y direction;

[0051] As shown in Figure 6 , it is a waveform diagram of the fluorescence intensity in the process of finding the single positioning channel at a uniform speed in the Y direction of the laser source. As shown in Figure 7 , assuming that at the X0 position, the single positioning channel is in the appropriate position of the laser spot, the focusing spot size of the single positioning channel is smaller than the single positioning channel, the fluorescence intensity waveform is narrow, and the fluorescence intensity amplitude is the highest; in the X- and X+ directions, the focusing spot size of the single positioning channel is larger than the single positioning channel, the fluorescence intensity waveform is wide, and the fluorescence intensity amplitude is reduced. As shown in Figure 8 , it is a schematic diagram of the change of the fluorescence intensity and the waveform width at different X-axis positions.

[0052] S3-4, according to the size of the laser spot on the microfluidic channel analyzed in S3-3, the final appropriate position of the laser source is selected.

[0053] The present application optimizes the structure of the microfluidic chip, determines the X-axis position automatically by judging the size of the laser spot on the channel.

[0054] The present application reduces the scattering light intensity of the laser on the adjacent channel by adjusting the size of the laser spot on the channel, so as to achieve the purpose of suppressing the interference of the adjacent channel.

[0055] The above examples are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and it cannot limit the protection scope of the present application. Any modification made according to the spirit and essence of the main technical solution of the present application should be covered within the protection scope of the present application.

Claims

1. A microfluidic chip, characterized by, The microfluidic chip comprises a plurality of microfluidic channels and a single positioning channel; the single positioning channel is located on the right side of the plurality of microfluidic channels, and the single positioning channel is parallel to each microfluidic channel. The size of the laser spot on the channel is determined to form an automatic X-axis position determination.

2. The microfluidic chip of claim 1, wherein, The microfluidic channel adopts a structure of narrow in the middle and wide on both sides, and the narrow part in the middle is a fluorescence observation position.

3. The microfluidic chip of claim 2, wherein, The width of the single positioning channel is 1.3-2 times the width of the fluorescence observation position of the microfluidic channel.

4. A method for reducing the cross-talk between adjacent channels of a microfluidic chip, characterized in that, It comprises: S1, optimizing the structure of the microfluidic chip, setting a single positioning channel parallel to each microfluidic channel on the microfluidic chip, for determining the size of the focused spot of the laser source on the microfluidic chip; S2, building an optical detection circuit to detect the diffraction light intensity of the laser passing through the microfluidic chip; S3, building an automatic sample control platform to control the movement of the laser source, and then control the size and position of the focused spot on the microfluidic chip.

5. The method of claim 4, wherein the microfluidic chip is a polydimethylsiloxane (PDMS) chip. In S1, the single positioning channel is parallel to each microfluidic channel of the microfluidic chip, and the width of the single positioning channel is 1.5 times the width of the fluorescence observation position of the microfluidic channel.

6. The method of claim 5, wherein the microfluidic chip is a polydimethylsiloxane (PDMS) chip. In S2, the optical detection circuit comprises a photoelectric conversion module and a high-speed analog-digital conversion acquisition circuit connected thereto, the photoelectric conversion module and the laser source are located on opposite sides of the microfluidic chip, the laser is diffracted when passing through the microfluidic chip, and the photoelectric conversion module acquires the diffraction light intensity.

7. The method of claim 6, wherein the microfluidic chip is a polydimethylsiloxane (PDMS) chip. The method for controlling the movement of the laser source in S3 comprises: S3-1, establishing a three-dimensional coordinate system of X, Y and Z, the X-axis is perpendicular to the microfluidic chip, the Y-axis is parallel to the microfluidic chip and perpendicular to each microfluidic channel, and the Z-axis is parallel to the microfluidic chip and parallel to each microfluidic channel; S3-2, fixing the initial position of the laser source: positioning the X-direction to the position where the laser spot on the chip coincides with the microfluidic channel; positioning the Y-direction to the left of the single positioning channel, and positioning the Z-direction to the range between the two ends of the single positioning channel; S3-3, moving the laser source from near to far in the X-direction, and moving uniformly in the Y-direction every time the laser passes through the single positioning channel, and recording and analyzing the photoelectric conversion data to determine the size of the laser spot on the single positioning channel; S3-4, according to the size of the laser spot on the microfluidic channel analyzed in S3-3, selecting the final appropriate position of the laser source.

8. The method for reducing the interference between adjacent channels of a microfluidic chip according to claim 7, wherein, In S3-3, the photoelectric conversion data includes the waveform width and amplitude of the fluorescence intensity.

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