Extremum screening system and method based on microfluidic technology

Abstract

The invention discloses an extreme value screening system and method based on a micro-fluidic technology. The extreme value screening system comprises a micro-fluidic chip; the micro-channel is arranged on the micro-fluidic chip; the flow direction control mechanism is connected with the micro-channel; the detector is arranged below the micro-fluidic chip; the controller is electrically connected with the micro-fluidic chip, the flow direction control mechanism and the detector respectively. According to the method, efficient extreme value screening is achieved, the most specific or most functional samples and a series of samples with the same characterization intensity gradually changed can be screened out, the extreme value samples can be analyzed easily, and the method has excellent popularization value.

Description

Technical Field

[0001] The present invention relates to the technical field of sample screening, and particularly to an extreme value screening system and method based on microfluidic technology. Background Art

[0002] Microfluidic screening technology has currently been applied in multiple research fields, and significant progress has been made especially in bacterial screening, genomics research, protein analysis, etc. Traditional microfluidic screening mainly realizes the selection of target substances in two ways: one is "negative / positive" qualitative screening, that is, after a fluorescent probe binds to a target molecule, the presence or absence of the target molecule is judged according to whether a fluorescent signal is emitted; the other is "threshold" quantitative screening, by monitoring the relationship between the intensity of the fluorescent signal and the concentration of the target molecule to achieve quantitative screening of the target molecule. Although these two methods have been widely used, there are still some technical bottlenecks when facing high-throughput extreme value screening tasks.

[0003] Although traditional "threshold" quantitative screening can judge the concentration of the target molecule according to the intensity of the fluorescent signal, due to the wide variety of bacteria and complex genetic backgrounds in the sample, it is difficult to effectively distinguish samples with the best or worst characteristics by presetting a threshold. Only several samples greater than / less than the threshold can be screened out, which limits the screening of strains with the strongest or weakest specific functions. Since the detection characteristic values of bacteria may vary greatly, it is difficult to screen out extreme value strains with special functions only relying on simple "negative / positive" determination or "threshold" screening. Summary of the Invention

[0004] In view of the above defects or deficiencies in the prior art, it is desirable to provide an extreme value screening system and method based on microfluidic technology, which realizes efficient extreme value screening, can screen out the most specific or most functional samples, as well as a series of samples with the same gradually changing characterization intensity, is conducive to the analysis of extreme value samples, and has excellent promotion value.

[0005] An extreme value screening system based on microfluidic technology provided by the present invention is characterized by comprising:

[0006] A microfluidic chip;

[0007] A microchannel, arranged on the microfluidic chip, used for forming a water-in-oil sample and cooperating to complete the screening of extreme value samples and a series of samples with the same gradually changing characterization intensity;

[0008] A flow direction control mechanism, connected to the microchannel, used for respectively controlling the flow directions of samples that meet the requirements and those that do not meet the requirements;

[0009] A detector, disposed below the microfluidic chip, is configured to perform feature detection on a sample in the microchannel before the flow control mechanism and obtain a detection feature value.

[0010] A controller is electrically connected to the microfluidic chip, the flow control mechanism, and the detector respectively.

[0011] Further, the microchannel includes a first liquid inlet channel, a second liquid inlet channel, and a mixing channel. The first end of the first liquid inlet channel is a first liquid inlet, the first end of the second liquid inlet channel is a second liquid inlet, and the second end of the first liquid inlet channel, the second end of the second liquid inlet channel, and the first end of the mixing channel are connected to form a mixing point. The second end of the first liquid inlet channel is divided into two branches and connected to both sides of the second end of the second liquid inlet channel, and is distributed in a cross shape with the second liquid inlet channel and the mixing channel.

[0012] The second end of the mixing channel is respectively connected to the first end of the first screening channel and the first end of the second screening channel to form a first screening point. The second end of the first screening channel is a first liquid outlet. The second end of the second screening channel is respectively connected to the first end of the third screening channel and the first end of the fourth screening channel to form a second screening point. The second end of the third screening channel is a second liquid outlet, and the second end of the fourth screening channel is a sampling port.

[0013] Further, the flow control mechanism includes a first rotary valve disposed at the first screening point and a second rotary valve disposed at the second screening point. The first rotary valve is in transmission connection with a first micro stepping motor, and the second rotary valve is in transmission connection with a second micro stepping motor.

[0014] Further, a plurality of narrow channels arranged side by side are connected to one side of the mixing channel, configured to screen out samples with a smaller outer diameter and discharge part of the oil liquid at the same time, thereby slowing down the flow rate of the samples.

[0015] Further, a first S-shaped channel is provided on the mixing channel between the mixing point and the narrow channels; a second S-shaped channel is provided on the mixing channel between the narrow channels and the first screening point.

[0016] Further, one ends of the plurality of narrow channels arranged side by side away from the mixing channel are all connected to a first storage bottle, and the first liquid outlet and the second liquid outlet are both connected to a second storage bottle.

[0017] Further, the detector is an ultraviolet-visible spectrophotometer, an infrared spectrometer, an atomic spectrometer, a fluorescence spectrometer, or a Raman spectrometer.

[0018] Further, the controller is an Arduino central controller.

[0019] In addition, the present invention also provides a screening method using the above-mentioned extreme value screening system based on microfluidic technology, including the following steps:

[0020] 1) Inject the oil liquid from one inlet of the microchannel, and then inject the aqueous solution containing the sample from the other inlet of the microchannel. Using different injection rates, form water-in-oil samples arranged one by one; wherein, the sample is labeled with a detection label.

[0021] 2) Detect the characteristics of each sample one by one through a detector, and screen the samples according to the extreme value screening algorithm; the extreme value screening algorithm includes a maximum value screening algorithm and a minimum value screening algorithm.

[0022] The maximum value screening algorithm is as follows:

[0023] Obtain the detection characteristic value γ1 of the first sample, and introduce it into the second screening channel of the microchannel through the flow direction control mechanism for retention, and use its detection characteristic value γ1 as the current reference value.

[0024] Obtain the detection characteristic value γ2 of the second sample. If γ2 is less than or equal to the current reference value, introduce it into the first screening channel of the microchannel through the flow direction control mechanism for screening out; if γ2 is greater than the current reference value, introduce it into the second screening channel through the flow direction control mechanism and retain it after the first sample, and update the current reference value to the detection characteristic value γ2.

[0025] And so on, obtain the detection characteristic value γ of the nth sample n , if γ n is less than or equal to the current reference value, introduce it into the first screening channel through the flow direction control mechanism for screening out; if γ n is greater than the current reference value, introduce it into the second screening channel through the flow direction control mechanism and arrange it after the previously retained sample, and update the current reference value to the detection characteristic value γ n , until all samples are screened; at this time, the detection characteristic values of the samples in the second screening channel gradually increase from front to back according to the flow direction of the samples, and the detection characteristic value of the last one is the largest among all samples.

[0026] The minimum value screening algorithm is as follows:

[0027] Obtain the detection characteristic value γ1 of the first sample, and introduce it into the second screening channel of the microchannel through the flow direction control mechanism for retention, and use its detection characteristic value γ1 as the current reference value.

[0028] Obtain the detection eigenvalue γ2 of the second sample. If γ2 is greater than or equal to the current reference value, it is screened out by the flow control mechanism and introduced into the first screening channel; if γ2 is less than the current reference value, it is introduced into the second screening channel by the flow control mechanism and retained after the first sample, and the current reference value is updated to the detection eigenvalue γ2;

[0029] And so on, obtain the detection eigenvalue γ of the nth sample n , if γ n is greater than or equal to the current reference value, it is screened out by the flow control mechanism and introduced into the first screening channel; if γ n is less than the current reference value, it is introduced into the second screening channel by the flow control mechanism and arranged after the previously retained sample, and the current reference value is updated to the detection eigenvalue γ n , until all samples are screened; at this time, the detection eigenvalues of the samples in the second screening channel gradually decrease from front to back according to the flow direction of the samples, and the detection eigenvalue of the last one is the smallest among all samples;

[0030] 3) Sample the samples in the second screening channel one by one.

[0031] Furthermore, a preset number of samples are retained in the second screening channel; when the number of samples retained in the second screening channel is greater than the preset number, the sample at the forefront is screened out and introduced into the third screening channel by the flow control mechanism; when all samples are screened, the samples retained in the second screening channel are introduced into the fourth screening channel by the flow control mechanism and sampled one by one.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] Based on microfluidic technology, through the precise design of the geometric structure of the microchannel and the detector, and combined with the extreme value screening algorithm, the present invention breaks through the limitations of traditional screening technologies, and can efficiently and accurately screen the individuals with the strongest or weakest functions in the bacterial population, as well as a series of samples with the same gradually changing characterization intensity in the microfluidic system, which is conducive to the analysis of extreme value samples. It can not only accelerate the discovery of new functional strains, but also be widely applied in fields such as drug research and development, biopharmaceuticals, and environmental monitoring, providing strong technical support for the development of related industries and having excellent promotion value.

[0034] It should be understood that the content described in the invention content part is not intended to limit the key or important features of the embodiments of the present invention, nor to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non - limiting embodiments read in conjunction with the accompanying drawings:

[0036] Figure 1 It is a schematic diagram of the modules of an extreme value screening system;

[0037] Figure 2 It is a schematic structural diagram of the microfluidic channels on a microfluidic chip.

[0038] Reference numerals in the figure: 1, microfluidic chip; 2, microfluidic channel; 3, flow direction control mechanism; 4, detector; 5, first storage bottle; 6, second storage bottle;

[0039] 21, first liquid inlet channel; 22, second liquid inlet channel; 23, mixing channel; 24, mixing point; 25, first screening channel; 26, second screening channel; 27, third screening channel; 28, fourth screening channel; 29, first S - shaped channel; 210, narrow channel; 211, second S - shaped channel;

[0040] 31, first rotary valve; 32, second rotary valve; 33, first micro - stepping motor; 34, second micro - stepping motor. Detailed implementation manners

[0041] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention, rather than limiting the invention. Additionally, it should be noted that for the sake of description, only the parts related to the invention are shown in the drawings.

[0042] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and embodiments.

[0043] Please refer to Figures 1 to 2 , an embodiment of the present invention provides an extreme value screening system based on microfluidic technology, including:

[0044] A microfluidic chip 1;

[0045] A microfluidic channel 2, disposed on the microfluidic chip 1, used to form a water - in - oil sample and cooperate to complete the screening of extreme value samples and a series of samples with gradually changing same characterization intensities;

[0046] A flow direction control mechanism 3, connected to the microfluidic channel 2, used to respectively control the flow directions of samples that meet the requirements and those that do not meet the requirements;

[0047] A detector 4, disposed below the microfluidic chip 1, used to perform feature detection on the samples in the microfluidic channel 2 before the flow direction control mechanism 3 and obtain detection feature values;

[0048] A controller, which is electrically connected to the microfluidic chip 1, the flow direction control mechanism 3, and the detector 4 respectively.

[0049] In this embodiment, when screening the samples, the oil liquid and the aqueous solution containing the samples are respectively injected into the microchannel 2 to form water-in-oil samples arranged one by one, and the samples carry detection marks; then the samples are detected for characteristics one by one, and the detected characteristic value of the current sample is compared with the maximum detected characteristic value or the minimum detected characteristic value of the samples that have been detected before. The samples that meet the requirements are retained in the microchannel 2, and the samples that do not meet the requirements are screened out through the microchannel 2 until all the samples are screened.

[0050] This application realizes efficient extreme value screening, can screen out the most specific or most functional samples, as well as a series of samples with the same characterization intensity changing gradually, that is, several samples with the largest detected characteristic value and decreasing in turn, which is beneficial to the analysis of extreme value samples and has excellent popularization value.

[0051] In a preferred embodiment, as Figure 1 and Figure 2 shown, the microchannel 2 includes a first liquid inlet channel 21, a second liquid inlet channel 22, and a mixing channel 23. The first end of the first liquid inlet channel 21 is the first liquid inlet, the first end of the second liquid inlet channel 22 is the second liquid inlet, and the second end of the first liquid inlet channel 21, the second end of the second liquid inlet channel 22, and the first end of the mixing channel 23 are connected to form a mixing point 24; the second end of the first liquid inlet channel 21 is divided into two branches and connected to both sides of the second end of the second liquid inlet channel 22, and is distributed in a cross shape with the second liquid inlet channel 22 and the mixing channel 23;

[0052] The second end of the mixing channel 23 is respectively connected to the first end of the first screening channel 25 and the first end of the second screening channel 26 to form a first screening point. The second end of the first screening channel 25 is the first liquid outlet. The second end of the second screening channel 26 is respectively connected to the first end of the third screening channel 27 and the first end of the fourth screening channel 28 to form a second screening point. The second end of the third screening channel 27 is the second liquid outlet, and the second end of the fourth screening channel 28 is the sampling port.

[0053] In this embodiment, the oil liquid in the first liquid inlet channel 21 has a faster flow rate, and the two branches of the first liquid inlet channel 21 are distributed in a cross shape with the second liquid inlet channel 22 and the mixing channel 23, so that the shear force of the oil liquid at the mixing point 24 is greater, and it is easier to form water-in-oil samples;

[0054] Before the sample flows to the first screening point, the detector 4 detects it, transmits its detected characteristic value to the controller, and compares it with the maximum or minimum detected characteristic value that has been detected previously (when screening the sample with the largest detected characteristic value, compare it with the largest one; when screening the sample with the smallest detected characteristic value, compare it with the smallest one). The samples that meet the requirements are introduced into the second screening channel 26 by the flow direction control mechanism 3 and arranged behind the previously retained sample, and the samples that do not meet the requirements are introduced into the first screening channel 25 by the flow direction control mechanism 3 and screened out.

[0055] When the number of samples retained in the second screening channel 26 reaches the preset number (determined by the designed length of the second screening channel 26), when a new sample enters the second screening channel 26, the sample at the forefront is introduced into the third screening channel 27 by the flow direction control mechanism 3 and screened out.

[0056] After all the samples are screened, the samples retained in the second screening channel 26 are introduced into the fourth screening channel 28 by the flow direction control mechanism 3 and sampled one by one through the sampling ports. The screening efficiency is high, ensuring that the samples with the largest or smallest detected characteristic values are accurately identified and sampled. Moreover, multiple continuously changing samples can be obtained, which is conducive to subsequent performance analysis.

[0057] In a preferred embodiment, as Figure 1 and Figure 2 shown, the flow direction control mechanism 3 includes a first rotary valve 31 arranged at the first screening point and a second rotary valve 32 arranged at the second screening point. The first rotary valve 31 is drivingly connected to a first micro stepping motor 33, and the second rotary valve 32 is drivingly connected to a second micro stepping motor 34.

[0058] In this embodiment, the flow direction of the detected sample is controlled by the first rotary valve 31 at the first screening point. The samples that meet the requirements flow down, and the samples that do not meet the requirements are screened out; the flow direction of the sample is controlled by the second rotary valve 32 at the second screening point, the samples exceeding the preset number are screened out, and after the screening is completed, the retained samples are guided for sampling, ensuring the accurate identification of the extreme value samples.

[0059] In a preferred embodiment, as Figure 2 shown, several narrow channels 210 are arranged side by side on one side of the mixing channel 23, which are used to screen out samples with smaller outer diameters and discharge part of the oil liquid at the same time, thereby slowing down the flow rate of the samples and extending the detection interval of the detector, ensuring the accuracy of the detection.

[0060] In a preferred embodiment, as Figure 2As shown, a first S-shaped flow channel 29 is provided on the mixing flow channel 23 between the mixing point 24 and the narrow flow channel 210 to ensure that the sample after the oil-in-water formation is stably arranged; a second S-shaped flow channel 211 is provided on the mixing flow channel 23 between the narrow flow channel 210 and the first screening point to screen out the small-sized samples and then pass through the second S-shaped flow channel 211 to ensure stable, continuous and uniform flow of the samples.

[0061] In a preferred embodiment, if Figure 2 As shown, the ends of several parallel narrow channels 210 away from the mixing channel 23 are all connected to the first storage bottle 5, and the small particle size samples screened out by the narrow channel 210 enter the first storage bottle 5 for collection; the first liquid outlet and the second liquid outlet are both connected to the second storage bottle 6, and the samples screened out by the first screening channel 25 and the third screening channel 27 enter the second storage bottle 6 for collection.

[0062] In a preferred embodiment, the detector is a UV-visible spectrophotometer, an infrared spectrometer, an atomic spectrometer, a fluorescence spectrometer or a Raman spectrometer.

[0063] In this embodiment, the UV-Vis Spectrophotometer decomposes the composite light emitted by the light source (deuterium lamp / tungsten lamp) into monochromatic light through a monochromator. After the sample to be tested absorbs light of a specific wavelength, the detector (photodiode or PMT) measures the change in the intensity of the transmitted light to obtain a curve of the relationship between absorbance and wavelength. The absorbance intensity at a specific wavelength position is used as a characteristic reference scalar.

[0064] Infrared spectrometers include Fourier transform infrared spectrometers (FTIR) and dispersive infrared spectrometers; Fourier transform infrared spectrometers (FTIR) use Michelson interferometers to modulate infrared light into interference patterns, and convert them into spectral signals through Fourier transform; dispersive infrared spectrometers use gratings or prisms to split light and detect infrared light absorbed by samples wavelength by wavelength; the infrared light intensity at a specific wavelength position is used as a characteristic reference scalar;

[0065] Atomic spectrometers include atomic absorption spectrometers (AAS) and atomic emission spectrometers (AES). Atomic absorption spectrometers (AAS) use hollow cathode lamps of the element to be measured to emit characteristic spectral lines, which are absorbed by ground-state atoms in the atomized sample, and the detector measures the absorbance change. Atomic emission spectrometers (AES) emit characteristic spectra after the sample is excited (such as inductively coupled plasma, ICP), and the element content is detected by spectroscopy. The light intensity at a specific wavelength position is used as a characteristic reference scalar.

[0066] A fluorescence spectrometer uses excitation light (such as a xenon lamp or a laser) to irradiate a sample, causing it to emit fluorescence. The fluorescence signals of different wavelengths are separated by a monochromator, and the light intensity at a specific wavelength position is used as a characteristic reference scalar.

[0067] A Raman spectrometer uses a monochromatic laser to irradiate a sample, generating Raman scattering (inelastically scattered light). By detecting the frequency shift of the scattered light, molecular vibration information is obtained, and the light intensity at a specific wavelength position is used as a characteristic reference scalar.

[0068] In some embodiments, any detector that uses a light source to irradiate a sample, the sample generates a characteristic spectrum, and the light intensity at the characteristic wavelength position in the spectrum is used as a reference scalar can apply the technical solution of this application to achieve extreme value screening; in other embodiments, as long as the detector measures the "characteristic scalar", it can be used as a reference standard to further achieve extreme value screening.

[0069] In a preferred embodiment, the controller is an Arduino central controller, which is used to control the microfluidic chip 1, the flow direction control mechanism 3, and the detector 4.

[0070] Also, please refer to Figures 1 to 2 , the embodiments of the present invention also provide a screening method using the above-mentioned extreme value screening system based on microfluidic technology, including the following steps:

[0071] 1) Inject the oil liquid from one inlet of the microchannel 2, and then inject the aqueous solution containing the sample from the other inlet of the microchannel 2. Using different injection rates, a water-in-oil sample arranged one by one is formed; among them, the sample is marked with a detection label.

[0072] 2) Detect the characteristics of each sample one by one through the detector 4, and obtain the detection characteristic values. Screen the samples according to the extreme value screening algorithm; the extreme value screening algorithm includes a maximum value screening algorithm and a minimum value screening algorithm.

[0073] The maximum value screening algorithm is as follows:

[0074] Obtain the detection characteristic value γ1 of the first sample, and introduce it into the second screening channel 26 of the microchannel 2 through the flow direction control mechanism 3 for retention, and use its detection characteristic value γ1 as the current reference value.

[0075] Obtain the detection characteristic value γ2 of the second sample. If γ2 is less than or equal to the current reference value, introduce it into the first screening channel 25 of the microchannel 2 through the flow direction control mechanism 2 for screening out; if γ2 is greater than the current reference value, introduce it into the second screening channel 26 through the flow direction control mechanism 3 and retain it after the first sample, and update the current reference value to the detection characteristic value γ2.

[0076] And so on, obtain the detection eigenvalue γ of the nth sample n , if γ n is less than or equal to the current reference value, then it is introduced into the first screening channel 25 through the flow direction control mechanism 3 for screening; if γ n is greater than the current reference value, then it is introduced into the second screening channel 26 through the flow direction control mechanism 3 and arranged after the previously retained sample, and the current reference value is updated to the detection eigenvalue γ n , until all samples are screened; at this time, the detection eigenvalues of the samples in the second screening channel 26 gradually increase from front to back according to the flow direction of the samples, and the detection eigenvalue of the last one is the largest among all samples;

[0077] The minimum value screening algorithm is as follows:

[0078] Obtain the detection eigenvalue γ1 of the first sample, introduce it into the second screening channel 26 through the flow direction control mechanism 3 for retention, and use its detection eigenvalue γ1 as the current reference value;

[0079] Obtain the detection eigenvalue γ2 of the second sample. If γ2 is greater than or equal to the current reference value, then it is introduced into the first screening channel 25 through the flow direction control mechanism 3 for screening; if γ2 is less than the current reference value, then it is introduced into the second screening channel 26 through the flow direction control mechanism 3 and arranged after the first sample for retention, and the current reference value is updated to the detection eigenvalue γ2;

[0080] And so on, obtain the detection eigenvalue γ of the nth sample n , if γ n is greater than or equal to the current reference value, then it is introduced into the first screening channel 25 through the flow direction control mechanism 3 for screening; if γ n is less than the current reference value, then it is introduced into the second screening channel 26 through the flow direction control mechanism 3 and arranged after the previously retained sample, and the current reference value is updated to the detection eigenvalue γ n , until all samples are screened; at this time, the detection eigenvalues of the samples in the second screening channel 26 gradually decrease from front to back according to the flow direction of the samples, and the detection eigenvalue of the last one is the smallest among all samples;

[0081] Among them, a preset number of samples are retained in the second screening channel 26; when the number of samples retained in the second screening channel 26 is greater than the preset number, the sample at the forefront is introduced into the third screening channel 27 through the flow direction control mechanism 3 for screening;

[0082] 3) After all samples are screened, the samples retained in the second screening channel 26 are introduced into the fourth screening channel 28 through the flow direction control mechanism 3, and sampling is carried out one by one respectively.

[0083] In this embodiment, the conduction state of the first rotary valve 31 is controlled by the first micro stepping motor 33. Under normal circumstances, the first rotary valve 31 connects the mixing flow channel 23 and the first screening flow channel 25. When the detection characteristic value of the sample does not meet the requirements, it enters the first screening flow channel 25 through the first rotary valve 31 and is screened out; when the detection characteristic value of the sample meets the requirements, the first rotary valve 31 turns to connect the mixing flow channel 23 and the second screening flow channel 26, and the sample enters the second screening flow channel 26 through the first rotary valve 31 and is retained;

[0084] The conduction state of the second rotary valve 32 is controlled by the second micro stepping motor 34. Under normal circumstances, the second rotary valve 32 connects the second screening flow channel 26 and the third screening flow channel 25. When the number of samples retained in the second screening flow channel 26 reaches the preset quantity, the sample at the forefront enters the third screening flow channel 25 through the second rotary valve 32 and is screened out; when all the samples are completely screened, the second rotary valve 32 turns to connect the second screening flow channel 26 and the fourth screening flow channel 28; at this time, the first rotary valve 31 connects the mixing flow channel 23 and the second screening flow channel 26, and the samples retained in the second screening flow channel 26 enter the fourth screening flow channel 28 through the second rotary valve 32, and are sampled one by one through the sampling port.

[0085] The detector is very close to the position of the first rotary valve 31, and the flow rate of the samples in the microchannel 2 is basically kept consistent (controlled by the microfluidic device). The time interval for each rotation of the first rotary valve 31 to change the flow channel is fixed, which can ensure that the samples meeting the requirements enter the second screening flow channel 26.

[0086] After all the screening is completed, the samples stored in the second screening flow channel 26 are valid samples and serve as the research objects. And from the second rotary valve 32 to the first rotary valve 31, the detection characteristic values of the samples increase or decrease in sequence, and the detection characteristic value closest to the first rotary valve 31 is the highest or lowest among all the samples.

[0087] The samples that enter the third screening flow channel 27 from the second screening flow channel 26 through the second rotary valve 32 are all useless samples and are finally discharged through the second liquid outlet.

[0088] Based on microfluidic technology, through the precise design of the geometric structure of the microchannel 2 and the detector 4, and combined with the extreme value screening algorithm, this application breaks through the limitations of traditional screening technologies, and can efficiently and accurately screen the individuals with the strongest or weakest functions in the bacterial population, as well as a series of samples with the same characterization intensity gradient in the microfluidic system, which is conducive to the analysis of extreme value samples. It can not only accelerate the discovery of new functional strains, but also be widely applied in fields such as drug R & D, biopharmaceuticals, and environmental monitoring, providing strong technical support for the development of related industries and having excellent promotion value.

[0089] In the description of this specification, terms such as "connection", "installation", "fixation", etc. should all be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0090] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0091] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. An extreme value screening system based on microfluidic technology, characterized in that include: Microfluidic chip (1); A microchannel (2) is arranged on the microfluidic chip (1) and is used to form a water-in-oil sample and cooperate to complete the screening of extreme value samples and a series of samples with the same characteristic intensity gradient; A flow direction control mechanism (3), connected to the microfluidic channel (2), for controlling the flow directions of samples that meet the requirements and samples that do not meet the requirements respectively; A detector (4) is arranged below the microfluidic chip (1) and is used to perform characteristic detection on the sample located before the flow direction control mechanism (3) in the microchannel (2) and obtain a detection characteristic value; The controller is electrically connected to the microfluidic chip (1), the flow direction control mechanism (3) and the detector (4) respectively.

2. The extreme value screening system based on microfluidic technology according to claim 1, characterized in that The microfluidic channel (2) comprises a first liquid inlet channel (21), a second liquid inlet channel (22) and a mixing channel (23); the first end of the first liquid inlet channel (21) is a first liquid inlet port, the first end of the second liquid inlet channel (22) is a second liquid inlet port, the second end of the first liquid inlet channel (21), the second end of the second liquid inlet channel (22) and the first end of the mixing channel (23) are connected to form a mixing point (24); the second end of the first liquid inlet channel (21) is divided into two branches connected to two sides of the second end of the second liquid inlet channel (22), and are distributed in a cross shape with the second liquid inlet channel (22) and the mixing channel (23); The second end of the mixing channel (23) is respectively connected to the first end of the first screening channel (25) and the first end of the second screening channel (26) to form a first screening point, the second end of the first screening channel (25) is a first liquid outlet, the second end of the second screening channel (26) is respectively connected to the first end of the third screening channel (27) and the first end of the fourth screening channel (28) to form a second screening point, the second end of the third screening channel (27) is a second liquid outlet, and the second end of the fourth screening channel (28) is a sampling port.

3. The extreme value screening system based on microfluidic technology according to claim 2, wherein The flow direction control mechanism (3) comprises a first rotary valve (31) arranged at the first screening point and a second rotary valve (32) arranged at the second screening point, the first rotary valve (31) being transmission-connected to a first micro-stepping motor (33), and the second rotary valve (32) being transmission-connected to a second micro-stepping motor (34).

4. The extreme value screening system based on microfluidic technology according to claim 2, characterized in that, One side of the mixing flow channel (23) is connected to a plurality of parallel narrow flow channels (210) for screening out samples with a smaller outer diameter and discharging part of the oil at the same time, thereby slowing down the flow rate of the sample.

5. The extreme value screening system based on microfluidic technology according to claim 4, characterized in that, A first S-shaped flow channel (29) is provided on the mixing flow channel (23) between the mixing point (24) and the narrow flow channel (210); and a second S-shaped flow channel (211) is provided on the mixing flow channel (23) between the narrow flow channel (210) and the first screening point.

6. The extreme value screening system based on microfluidic technology according to claim 4, wherein, The ends of the plurality of parallel narrow flow channels (210) away from the mixing flow channel (23) are all connected to the first storage bottle (5); the first liquid outlet and the second liquid outlet are both connected to the second storage bottle (6).

7. The extreme value screening system based on microfluidic technology according to claim 2, wherein The detector (4) is an ultraviolet-visible spectrophotometer, an infrared spectrometer, an atomic spectrometer, a fluorescence spectrometer or a Raman spectrometer.

8. The extreme value screening system based on microfluidic technology according to claim 1, characterized in that The controller is an Arduino central controller.

9. A screening method using the extreme value screening system based on microfluidic technology according to any one of claims 1-8, characterized in that, It includes the following steps: 1) Inject the oil fluid from one inlet of the microchannel (2), and then inject the aqueous solution containing the sample from the other inlet of the microchannel (2). Using different injection rates, form water-in-oil samples arranged one by one; wherein, the samples are marked with detection markers. 2) Detect the characteristics of each sample one by one through the detector (4), and obtain the detection characteristic values. Screen the samples according to the extreme value screening algorithm; the extreme value screening algorithm includes a maximum value screening algorithm and a minimum value screening algorithm. The maximum value screening algorithm is as follows: Obtain the detection characteristic value γ1 of the first sample, and introduce it into the second screening channel (26) of the microchannel (2) for retention through the flow direction control mechanism (3), and use its detection characteristic value γ1 as the current reference value. Obtain the detection characteristic value γ2 of the second sample. If γ2 is less than or equal to the current reference value, introduce it into the first screening channel (25) of the microchannel (2) for screening through the flow direction control mechanism (3); if γ2 is greater than the current reference value, introduce it into the second screening channel (26) for retention after the first sample through the flow direction control mechanism (3), and update the current reference value to the detection characteristic value γ2. And so on, obtain the detection eigenvalue γ of the nth sample n , if γ n is less than or equal to the current reference value, it is screened out by being introduced into the first screening channel (25) through the flow direction control mechanism (3); if γ n is greater than the current reference value, it is introduced into the second screening channel (26) through the flow direction control mechanism (3) and arranged after the previously retained sample, and the current reference value is updated to the detection eigenvalue γ n , until all samples are screened; at this time, the detection eigenvalues of the samples in the second screening channel (26) gradually increase from front to back according to the flow direction of the samples, and the detection eigenvalue of the last one is the largest among all samples; The minimum value screening algorithm is as follows: Obtain the detection characteristic value γ1 of the first sample, and introduce it into the second screening channel (26) for retention through the flow direction control mechanism (3), and use its detection characteristic value γ1 as the current reference value. Obtain the detection characteristic value γ2 of the second sample. If γ2 is greater than or equal to the current reference value, introduce it into the first screening channel (25) of the microchannel (2) for screening through the flow direction control mechanism (3); if γ2 is less than the current reference value, introduce it into the second screening channel (26) for retention after the first sample through the flow direction control mechanism (3), and update the current reference value to the detection characteristic value γ2. By analogy, the detection eigenvalue γ of the nth sample is obtained n , if γ n is greater than or equal to the current reference value, it is screened out by being introduced into the first screening channel (25) through the flow control mechanism (3); if γ n is less than the current reference value, it is introduced into the second screening channel (26) through the flow control mechanism (3) and arranged after the previously retained sample, and the current reference value is updated to the detection eigenvalue γ n , until all samples are screened; at this time, the detection eigenvalues of the samples in the second screening channel (26) gradually decrease from front to back according to the flow direction of the samples, and the detection eigenvalue of the last one is the smallest among all samples; 3) Sample the samples in the second screening channel (26) one by one.

10. The screening method according to claim 9, wherein A preset number of samples are retained in the second screening channel (26); when the number of samples retained in the second screening channel (26) is greater than the preset number, the sample at the front end according to the sample flow direction is introduced into the third screening channel (27) for screening through the flow direction control mechanism (3); when all the samples are screened, the samples retained in the second screening channel (26) are introduced into the fourth screening channel (28) through the flow direction control mechanism (3), and sampled one by one.

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