A microfluidic chip, a microfluidic system, a compound detection method based on the microfluidic system, and its applications.

Abstract

This invention provides a microfluidic chip, a microfluidic system, a compound detection method based on the microfluidic system, and its applications. The compound detection method based on the microfluidic system provided by this invention highly integrates the detection steps of the traditional tyrosinase assay onto a microfluidic chip. The microfluidic chip has a micrometer-scale main channel. After the sample to be tested is introduced into the generation region of the main channel, a large number of microdroplets are formed. These microdroplets act as reaction containers, reacting with tyrosine and tyrosinase introduced into the reaction region of the main channel. Finally, the absorbance of the microdroplets can be measured in the detection region of the main channel. The microdroplets are small in size and have a high surface area to volume ratio, enabling them to form highly efficient reaction containers. The microfluidic system can rapidly and accurately measure samples of different concentrations and also has advantages such as low reagent consumption, energy saving and environmental friendliness, small required detection space, and the ability to operate in parallel on a large scale.

Description

Technical Field

[0001] This invention belongs to the field of compound detection technology, and particularly relates to a microfluidic chip, a microfluidic system, a compound detection method based on the microfluidic system, and its application. Background Technology

[0002] Nowadays, more and more cosmetics with special effects are appearing in people's lives. With the widespread use of cosmetics in daily life and the continuous introduction of relevant laws and regulations, the efficacy of cosmetic products, and whether their efficacy has sufficient scientific basis, is receiving increasing attention.

[0003] Detection technologies for the efficacy of cosmetic ingredients have become a crucial link in the cosmetic industry chain. Taking whitening cosmetics as an example, in addition to already marketed ingredients such as niacinamide and arbutin, many more ingredients, such as those extracted from specific plants and animals, chemically synthesized organic derivatives, and biosynthesized proteins and amino acids, require testing, analysis, and evaluation for their whitening efficacy before being screened and ultimately applied in whitening cosmetics. With the deepening of research and the development of extraction and synthesis technologies, the number of such ingredients requiring testing, evaluation, and screening will continue to increase. Therefore, the research and development process of cosmetics places higher demands on the testing, evaluation, and screening of the specific efficacy of natural products or synthetic compounds used in cosmetics. The capability, efficiency, and cost of detection methods directly affect the subsequent research and development and production processes of efficacy cosmetics.

[0004] However, traditional methods have limitations when processing increasingly large volumes of samples, typically requiring high costs and lengthy processing times. Mainstream, mature detection methods remain relatively weak in detection capability and efficiency when faced with even larger quantities of samples presented as "chemical libraries," and are also costly, necessitating high-end, expensive equipment. In conclusion, considering the limitations of current methods for detecting whitening ingredients in cosmetic research and development, there is an urgent need to develop a detection device and method that can overcome these limitations and rapidly, efficiently, and accurately detect the components of large numbers of samples. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a microfluidic chip, a microfluidic system, and a compound detection method based on the microfluidic system, aiming to solve the problems of low detection efficiency and high detection cost of compounds in related technologies.

[0006] To address the aforementioned technical problems, the first aspect of this invention provides a microfluidic chip, comprising: a substrate, a main channel, and a detection device;

[0007] The main channel is disposed on the substrate, and the main channel includes a generation area, a reaction area and a detection area connected in sequence.

[0008] The generation area is connected to multiple liquid inlet channels, and at least one of the liquid inlet channels has a sample inlet for injecting the sample into the generation area.

[0009] The reaction zone is connected to multiple injection channels, each of which is used to inject tyrosine and tyrosinase respectively. The sample to be tested, the tyrosine and the tyrosinase can be mixed and reacted in the reaction zone and then flow to the detection zone.

[0010] The detection area is equipped with a sample outlet;

[0011] The detection device is used to detect the absorbance of microdroplets flowing through the detection area.

[0012] Furthermore, the generation area includes a first generation channel and a second generation channel;

[0013] At least a portion of the liquid inlet channels are respectively provided with an aqueous phase inlet and an oil phase inlet, the aqueous phase inlet and the oil phase inlet being used to inject an aqueous buffer solution and an oil phase liquid, respectively;

[0014] The first end of the first generation channel is connected to the aqueous phase inlet and the sample inlet, and the second end of the first generation channel is connected to the oil phase inlet and the second generation channel.

[0015] Furthermore, the cross-sectional area of ​​the first generation channel is smaller than the cross-sectional area of ​​the second generation channel.

[0016] Furthermore, the microfluidic chip also includes microelectrode channels that can generate an electric field in the reaction region, which is used to provide an electric field force for injecting tyrosine and tyrosinase into the reaction region.

[0017] Furthermore, the detection device includes a first optical fiber and a second optical fiber;

[0018] The first optical fiber and the second optical fiber are disposed on the substrate. The first optical fiber is used to connect to the light source to output test light, which passes through the detection area in one direction. The second optical fiber is used to receive the test light after it passes through the detection area and is connected to the photodetector.

[0019] Furthermore, the detection device includes two micro-fiber channels, which are symmetrically arranged on both sides of the detection area, with the first optical fiber and the second optical fiber respectively fixed in each of the micro-fiber channels.

[0020] A second aspect of the present invention provides a microfluidic system, comprising: a control device, a liquid pumping device, a voltage amplifier, a light source, a photodetector, and a microfluidic chip as described above;

[0021] The control device is connected to the liquid pumping device, the voltage amplifier, the light source, and the photodetector;

[0022] The liquid pumping device is connected to multiple inlet channels and injection channels of the microfluidic chip. The liquid pumping device is used to pump the sample to be tested, aqueous buffer solution and oil liquid into each of the inlet channels respectively. The liquid pumping device is also used to pump tyrosine and tyrosinase into each of the injection channels respectively.

[0023] The voltage amplifier is electrically connected to the voltage signal port and the ground port of the microelectrode channel;

[0024] The light source is connected to the first optical fiber of the microfluidic chip, and the light source is used to output test light into the first optical fiber. The test light passes through the detection area of ​​the microfluidic chip in one direction.

[0025] The photodetector is connected to the second optical fiber of the microfluidic chip. The second optical fiber receives the test light after passing through the detection area. The photodetector is used to detect the absorbance of the microdroplets flowing through the detection area.

[0026] The present invention also provides a compound detection method based on the above-mentioned microfluidic system, comprising the following steps:

[0027] Prepare microfluidic chips;

[0028] The multiple inlet channels and multiple injection channels of the microfluidic chip are connected to a liquid pumping device;

[0029] The microelectrode channels of the microfluidic chip are electrically connected to the voltage amplifier;

[0030] The first optical fiber of the microfluidic chip is connected to the light source, and the second optical fiber of the microfluidic chip is connected to the photodetector.

[0031] The liquid pumping device pumps the sample to be tested, aqueous buffer solution and oil liquid into the liquid inlet channel, and generates microdroplets in the generation area of ​​the microfluidic chip.

[0032] Tyrosine and tyrosinase are pumped into the injection channel via the liquid pumping device, so that the tyrosine and the tyrosinase react with the microdroplets in the reaction area of ​​the microfluidic chip.

[0033] When the microdroplets after the reaction flow through the detection area of ​​the microfluidic chip, the photodetector detects the absorbance of the microdroplets.

[0034] Furthermore, the step of pumping the sample to be tested, aqueous buffer solution, and oil phase liquid into the inlet channel via the liquid pumping device, and generating microdroplets in the generation area of ​​the microfluidic chip, specifically includes:

[0035] The oil phase liquid is pumped at constant pressure into the inlet channel by the liquid pumping device.

[0036] The aqueous buffer solution is then pumped into the inlet channel at a constant pressure using the liquid pumping device at a first preset pressure.

[0037] The sample to be tested is pumped into the inlet channel by the liquid pumping device. Within a preset time, the pumping pressure of the sample to be tested increases uniformly from 0 to the first preset pressure. At the same time, the pumping pressure of the aqueous buffer solution decreases uniformly from the first preset pressure to 0. In this way, multiple microdroplets with a gradient increase in the concentration of the sample to be tested are formed in the generation zone.

[0038] Further, the step of pumping tyrosine and tyrosinase into the injection channel via the liquid pumping device, so that the tyrosine and the tyrosinase react with the microdroplets in the reaction region of the microfluidic chip, specifically includes:

[0039] The voltage amplifier is turned on to apply a voltage to the microelectrode channel, which can form an electric field in the reaction zone. The electric field provides an electric force for injecting tyrosine and tyrosinase into the injection channel.

[0040] Simultaneously, the liquid pumping device pumps an equal amount of tyrosine and tyrosinase into the injection channel at a constant pressure of the second preset pressure. Under the action of the electric field force and the second preset pressure, the tyrosine and tyrosinase are injected into the microdroplet, so that the tyrosine and the tyrosinase react with the microdroplet in the reaction zone of the microfluidic chip.

[0041] The present invention also discloses the application of the method described above in the efficacy testing of cosmetics.

[0042] Compared with existing technologies, the microfluidic chip, microfluidic system, compound detection method based on microfluidic system, and their applications in this invention have the following advantages:

[0043] The compound detection method based on a microfluidic system provided by this invention highly integrates the detection steps of traditional tyrosinase assays onto a microfluidic chip. The microfluidic chip has a micrometer-scale main channel. After the sample to be tested is introduced into the generation region of the main channel, a large number of microdroplets are formed. These microdroplets act as reaction vessels, reacting with tyrosine and tyrosinase introduced into the reaction region of the main channel. Finally, the absorbance of the microdroplets can be measured in the detection region of the main channel.

[0044] Microdroplets, with their small size and high surface area-to-volume ratio, can form highly efficient reaction vessels. By controlling the liquid inflow rate in each inlet and injection channel of the microfluidic chip, samples of different concentrations can be measured rapidly and accurately. The entire process is highly automated, reducing manual intervention and enabling batch testing results. Furthermore, since this invention is based on a microfluidic chip method, it also has advantages such as low reagent consumption, energy saving and environmental friendliness, small required testing space, and the ability to operate in parallel on a large scale. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the overall structure of the microfluidic chip in an embodiment of the present invention;

[0046] Figure 2 This is a partial structural schematic diagram of the microfluidic chip in an embodiment of the present invention;

[0047] Figure 3 yes Figure 2 Enlarged view at point 20a;

[0048] Figure 4 yes Figure 2 Enlarged view at point 20b;

[0049] Figure 5 yes Figure 2 Enlarged view at point 20c;

[0050] Figure 6 This is a schematic diagram of the microfluidic system in an embodiment of the present invention;

[0051] Figure 7 This is a flowchart illustrating the steps of an embodiment of the method of the present invention.

[0052] In the accompanying drawings, the reference numerals indicate:

[0053] 1. Microfluidic chip; 2. Liquid pumping device; 3. Voltage amplifier; 4. Light source; 5. Photodetector; 6. Automatic sampler; 7. Waste liquid collection device;

[0054] 10. Base;

[0055] 20. Main channel; 20a. Generation zone; 20b. Reaction zone; 20c. Detection zone; 210. Liquid inlet channel; 211. Aqueous phase inlet; 212. Sample inlet; 213. Oil phase inlet; 220. Injection channel; 230. Sample outlet; 241. First generation channel; 242. Second generation channel;

[0056] 30. Microelectrode channel; 310. Grounding port; 320. Voltage signal port;

[0057] 40. Micro-fiber channel; 410. Fiber main channel; 420. Auxiliary channel; 430. First fiber; 440. Second fiber;

[0058] 50. Curved channel. Detailed Implementation

[0059] In vitro skin whitening efficacy testing is a method used to evaluate the efficacy of skin whitening cosmetics or products. Tyrosinase testing is one of the commonly used methods. Traditional tyrosinase testing typically includes the following steps:

[0060] Sample preparation: Prepare the sample to be tested into a solution of standard concentration;

[0061] Tyrosinase reaction: Tyrosinase and tyrosine are added together to the sample to be tested, and the reaction occurs under certain conditions;

[0062] Determination of reaction products: By measuring the amount of reaction products or changes in tyrosinase activity, the effect of the test sample on tyrosinase can be evaluated, thereby indirectly assessing the efficacy of the test sample.

[0063] In related technologies, the equipment used for the aforementioned tyrosinase testing methods is complex, typically requiring a spectrophotometer, test tubes, microplates, temperature control equipment, and pipettes. This testing method necessitates multiple manual steps and precise reagent preparation, has a long reaction time, and is expensive due to the high cost of tyrosinase and tyrosine substrate reagents. Due to these limitations, to improve the accuracy and efficiency of detecting the efficacy of whitening cosmetics or products, there is an urgent need to design a more efficient and accurate detection device and method that overcomes the limitations of existing technologies.

[0064] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0065] Example:

[0066] Please see Figures 1 to 6 In this embodiment, a first aspect provides a microfluidic chip 1, including: a substrate 10, a main channel 20, and a detection device;

[0067] The main channel 20 is disposed on the substrate 10, and the main channel 20 includes a generation area 20a, a reaction area 20b and a detection area 20c connected in sequence.

[0068] The generation zone 20a is connected to multiple liquid inlet channels 210, and at least one liquid inlet channel 210 has a sample inlet 212 for injecting the sample to be tested into the generation zone 20a.

[0069] The reaction zone 20b is connected to multiple injection channels 220, each injection channel 220 is used to inject tyrosine and tyrosinase respectively. The test sample, tyrosine and tyrosinase can be mixed and reacted in the reaction zone 20b and then flow to the detection zone 20c.

[0070] The detection area 20c is equipped with a sample outlet 230;

[0071] The detection device is used to detect the absorbance of microdroplets flowing through the detection zone 20c.

[0072] In this embodiment, the microfluidic chip 1 has a micron-sized main channel 20. After the sample to be tested is introduced into the generation region 20a of the main channel 20, a large number of microdroplets are formed. The microdroplets act as reaction containers and react with tyrosine and tyrosinase introduced into the reaction region 20b of the main channel 20. Finally, the absorbance of the microdroplets can be measured in the detection region 20c of the main channel 20, and the microdroplets are discharged from the sample outlet 230 of the detection region 20c.

[0073] This design highly integrates the detection steps of the traditional tyrosinase assay onto the microfluidic chip 1. The microdroplets within the microfluidic chip 1 are small in volume and have a high surface area to volume ratio, enabling them to form highly efficient reaction containers. This results in low reagent consumption, energy saving, and environmental friendliness, while requiring minimal detection space. By controlling the liquid pumping flow rate of each inlet channel 210 and injection channel 220 of the microfluidic chip 1, samples of different concentrations can be measured quickly and accurately. The entire process is highly automated, reducing manual intervention, enabling batch testing and large-scale parallel operation.

[0074] In this embodiment, preferably, the substrate 10 comprises two bonded transparent substrates. The substrate 10 can be formed by bonding any one or more transparent substrates selected from polydimethylsiloxane (PDMS), quartz glass, polymethyl methacrylate (PMMA), and polycarbonate (PC). The main channel 20 is formed on a transparent substrate by photolithography / thermal embossing and other processes. The cross-section of the detection area 20c of the main channel 20 perpendicular to the extension direction is rectangular to ensure that the detection device can successfully test the absorbance of the microdroplets. It is understood that this embodiment does not limit the cross-sectional shape of the portion other than the detection area 20c of the main channel 20.

[0075] Furthermore, the generation area 20a includes a first generation channel 241 and a second generation channel 242;

[0076] At least a portion of the liquid inlet channel 210 is provided with an aqueous phase inlet 211 and an oil phase inlet 213, which are used to inject aqueous buffer solution and oil liquid, respectively.

[0077] The first end of the first generation channel 241 is connected to the aqueous phase inlet 211 and the sample inlet 212, and the second end of the first generation channel 241 is connected to the oil phase inlet 213 and the second generation channel 242.

[0078] like Figure 2 and 3 As shown, the first end of the first generation channel 241 is the junction of the aqueous buffer and the test sample in the main channel. The concentration of the test sample can be adjusted by controlling the flow rate of the aqueous buffer and the test sample into the first generation channel 241.

[0079] The second end of the first generation channel 241 is the junction of the concentration-adjusted sample solution and the oil phase liquid. The concentration-adjusted sample solution serves as the dispersed phase, and the oil phase liquid serves as the continuous phase. After the sample solution and the oil phase liquid meet, the sample solution is divided into tiny droplets and surrounded by the oil phase liquid. That is, at the second generation channel 242 connected to the second end of the first generation channel 241, the concentration-adjusted sample solution and the oil phase liquid form microdroplets.

[0080] Therefore, in this embodiment, the oil phase liquid can encapsulate sample solutions of different concentrations, and the multiple microdroplets formed by the microfluidic chip 1 can be effectively isolated from each other without cross-contamination. Each microdroplet is equivalent to a miniature reaction vessel, with fast transmission and reaction speeds, enabling high-throughput analysis and saving on sample and other experimental solvents.

[0081] Preferably, in this embodiment, at least two liquid inlet channels 210 with oil phase inlets 213 are included, and multiple liquid inlet channels 210 with oil phase inlets 213 are symmetrically arranged on both sides of the first generation channel 241 along the radial direction of the first generation channel 241. With this arrangement, the oil phase liquid can uniformly coat the sample solution to be tested.

[0082] Preferably, the cross-sectional area of ​​the inlet channel 210 with the aqueous phase inlet 211 and the inlet channel 210 with the sample inlet 212 is smaller than the cross-sectional area of ​​the junction with the first end of the first generation channel 241. This configuration ensures a more uniform velocity and flow state when the aqueous buffer solution and the sample meet, which is beneficial for precise control of the concentration of the sample solution and makes the size of the microdroplets more controllable.

[0083] It is understood that the number, cross-sectional shape, size and geometry of each liquid inlet channel 210 are not limited in other embodiments. Those skilled in the art can obtain the required liquid inlet flow rate and microdroplet size by reasonably designing the structure of the liquid inlet channel 210.

[0084] Furthermore, the cross-sectional area of ​​the first generation channel 241 is smaller than the cross-sectional area of ​​the second generation channel 242.

[0085] like Figure 3 As shown, the smaller cross-sectional area of ​​the first generation channel 241 helps the sample solution to have a more uniform velocity and flow state during subsequent diffusion or convergence, which is beneficial for generating uniformly sized microdroplets.

[0086] Preferably, the width of the second generation channel 242 is 100~200μm, and the width of the first generation channel 241 is 60~80μm.

[0087] Furthermore, the microfluidic chip 1 also includes a microelectrode channel 30, which can generate an electric field in the reaction zone 20b. The electric field is used to provide an electric force for injecting tyrosine and tyrosinase into the reaction zone 20b.

[0088] like Figure 4 As shown, in this embodiment, the microelectrode channel 30 includes a ground port 310 and a voltage signal port 320. The microelectrode channel 30 is filled with conductive material, and each ground port 310 and voltage signal port 320 is used to electrically connect to the voltage amplifier 3.

[0089] Specifically, the microelectrode channel 30 includes two voltage signal ports 320 and two ground ports 310 respectively corresponding to the two voltage signal ports 320. The two pairs of voltage signal ports 320 and ground ports 310 can form two electric fields. The two electric fields are used to provide electric field forces for tyrosine and tyrosinase to be injected into the reaction zone 20b, respectively, thereby controlling the injection rate of tyrosine and tyrosinase.

[0090] Furthermore, such as Figure 2 and 4 As shown, the reaction zone 20b also includes a curved channel 50. The injection channel 220 for injecting tyrosine, the injection channel 220 for injecting tyrosinase, and the curved channel 50 are arranged sequentially along the flow direction of the fluid in the microfluidic chip 1. That is, the curved channel 50 is located at one end of the reaction zone 20b near the detection zone 20c, and the injection channel 220 is located at one end of the reaction zone 20b near the generation zone 20a.

[0091] The curved channel 50 helps the multiple components inside the microdroplet to mix and disperse better, thereby promoting the contact and reaction between the sample, tyrosine and tyrosinase, increasing the contact area and improving the reaction rate.

[0092] Furthermore, since the size of the microfluidic chip 1 is typically in the millimeter range, the flow path of the reaction zone 20b of the microfluidic chip 1 is usually short, and the reaction time of the microdroplet in the reaction zone 20b is correspondingly short. Given a fixed area of ​​the reaction zone 20b, the curved channel 50 can extend the flow path of the microdroplet and prolong the residence time of the microdroplet in the reaction zone 20b, which is beneficial to improving the sufficiency of the reaction and further enhancing the accuracy of detection.

[0093] The curved channel 50 can also appropriately slow down the flow rate of microdroplets, which helps to reduce microdroplet breakage and improve the reliability of detection.

[0094] Preferably, the curved channel 50 has a periodically oscillating waveform or a loop shape. The amplitudes and frequencies of the curved channel 50 can be equal. In other embodiments, the amplitudes and frequencies of the curved channel 50 can be unequal, and the curved channel 50 can also be a non-periodic curved channel.

[0095] Preferably, the cross-sectional area of ​​the connection between the injection channel 220 and the reaction zone 20b of the main channel 20 is smaller than the cross-sectional area of ​​the injection channel 220 and the main channel 20.

[0096] On a projection plane perpendicular to the surface direction of the substrate 10, the dimensions perpendicular to the extension direction of the main channel 20, injection channel 220, and liquid inlet channel 210 are defined as widths. The width of the connection between the injection channel 220 and the reaction zone 20b of the main channel 20 is 10% to 25% of the width of either the injection channel 220 or the main channel 20. Specifically, in this embodiment, the cross-sectional area of ​​the connection between the injection channel and the reaction zone 20b of the main channel 20 is 15 μm, the cross-sectional area of ​​the injection channel 220 is 60 μm, and the radial diameter of the reaction zone 20b of the main channel 20 is 100 μm.

[0097] This configuration, due to the small cross-sectional area at the connection point of the reaction zone 20b between the injection channel 220 and the main channel 20, creates a contraction structure between the injection channel 220 and the main channel 20. This contraction structure results in a high curvature at the interface between the injected reagent injected through the injection channel 220 and the oil phase; specifically, a high curvature at the interface between tyrosine / tyrosinase and the oil phase liquid of the microdroplet. This creates a pressure difference, which, under the influence of the electric field, increases the interfacial instability between the oil and water phases, allowing tyrosine or tyrosinase to be accurately injected into the microdroplet. Furthermore, it effectively prevents fluid mixing and cross-contamination in different channels when no injection pressure is applied to tyrosine or tyrosinase.

[0098] Furthermore, such as Figure 5 As shown, the detection device includes a first optical fiber 430 and a second optical fiber 440.

[0099] The first optical fiber 430 and the second optical fiber 440 are disposed on the substrate 10. The first optical fiber 430 is used to connect the light source 4 to output test light. The test light passes through the detection area 20c in one direction. The second optical fiber 440 is used to receive the test light after passing through the detection area 20c and is connected to the photodetector 5.

[0100] Traditional tyrosinase testing methods involve sampling the test sample and measuring the absorbance of the liquid using a spectrophotometer, a complex sampling process.

[0101] In this embodiment, the first optical fiber 430 and the second optical fiber 440 are used to connect the light source 4 and the photodetector 5, respectively. The optical signal of the test light is transmitted through the first optical fiber 430 and the second optical fiber 440. The optical fiber structure is integrated onto the microfluidic chip 1, which simplifies the structure of the detection device, reduces the size of the detection device, and enables online detection, making it suitable for the needs of rapid detection.

[0102] Furthermore, such as Figure 5 As shown, the detection device includes two micro-fiber channels 40, which are symmetrically arranged on both sides of the detection area 20c. The first optical fiber 430 and the second optical fiber 440 are respectively fixed in each micro-fiber channel 40.

[0103] Two micro-fiber channels 40 are formed on the substrate 10, and the first fiber 430 and the second fiber 440 can be fixedly set in the corresponding micro-fiber channel 40.

[0104] Since the two micro-fiber channels 40 are symmetrically arranged on both sides of the detection area 20c, when the microdroplet passes between the first fiber 430 and the second fiber 440, the test light transmitted by the first fiber 430 passes through the microdroplet, and the test light that has passed through the microdroplet is received by the second fiber 440. The photodetector 5 connected to the second fiber 440 can detect the degree of absorption or transmission of the test light after passing through the microdroplet, thereby realizing the rapid detection of the components of the sample to be tested.

[0105] Furthermore, such as Figure 5As shown, each micro-fiber channel 40 includes a main fiber channel 410 and at least one auxiliary channel 420. The main fiber channels 410 of two micro-fiber channels 40 are symmetrically arranged on both sides of the detection area 20c. The auxiliary channel 420 is connected to the corresponding main fiber channel 410. The auxiliary channel 420 is filled with polymer, which abuts against and fixes the first fiber 430 / second fiber 440. Compared to designing and fabricating a structure within the micro-fiber channel 40 to fix the first fiber 430 / second fiber 440, the structure of a connected main fiber channel 410 and auxiliary channel 420 is more cost-effective.

[0106] In this embodiment, the auxiliary channel 420 is angled to the main fiber channel 410, and the two micro-fiber channels 40 are symmetrically arranged on both sides of the detection area 20c. It is understood that multiple auxiliary channels 420 can be provided, and it is not limited to only one auxiliary channel 420 in this embodiment.

[0107] Please see Figures 1 to 6 This embodiment also provides a microfluidic system, including: a control device (not shown in the figure), a liquid pumping device 2, a voltage amplifier 3, a light source 4, a photodetector 5, and a microfluidic chip 1 as described above;

[0108] The control device is connected to the liquid pumping device 2, voltage amplifier 3, light source 4, and photodetector 5;

[0109] The liquid pumping device 2 is connected to multiple liquid inlet channels 210 and injection channels 220 of the microfluidic chip 1. The liquid pumping device 2 is used to pump the sample to be tested, aqueous buffer solution and oil liquid into each liquid inlet channel 210 respectively. The liquid pumping device 2 is also used to pump tyrosine and tyrosinase into each injection channel 220 respectively.

[0110] The voltage amplifier 3 is electrically connected to the voltage signal port 320 and the ground port 310 of the microelectrode channel 30;

[0111] The light source 4 is connected to the first optical fiber 430 of the microfluidic chip 1. The light source 4 is used to output test light to the first optical fiber 430. The test light passes through the detection area 20c of the microfluidic chip 1 in one direction.

[0112] The photodetector 5 is connected to the second optical fiber 440 of the microfluidic chip 1. The second optical fiber 440 receives the test light after passing through the detection area 20c. The photodetector 5 is used to detect the absorbance of the microdroplets flowing through the detection area 20c.

[0113] The microfluidic system in this embodiment connects various components through a control device, achieving highly automated operation. The liquid pumping device 2 can precisely control the pumping of the test sample, aqueous buffer solution, and oil phase liquid. The voltage amplifier 3 ensures the accuracy of injecting tyrosine and tyrosinase into the microdroplets. The detection device, consisting of the light source 4, photodetector, first optical fiber 430, and second optical fiber 440, provides real-time optical detection. Furthermore, compared to traditional optical detection methods for test samples, in this embodiment, the light source 4 outputs test light to the microfluidic chip 1 through the first optical fiber 430, and the photodetector 5 receives the test light passing through the detection area 20c through the second optical fiber 440, enabling real-time detection of the microdroplet absorbance. This optical detection method features high sensitivity and rapid response, allowing for real-time monitoring of the internal reactions of the microdroplets.

[0114] Because the liquid pumping device 2 connects to multiple inlet channels 210 and injection channels 220 of the microfluidic chip 1, it can process multiple samples or reactants simultaneously, achieving rapid and efficient multi-channel operation. Furthermore, through the precise control of the liquid pumping device 2 and the high sensitivity of the photodetector 5, the system exhibits high precision and repeatability, enabling accurate experimental measurements and obtaining reliable results.

[0115] Furthermore, due to the miniature structure of the microfluidic chip 1, the system can perform experimental operations on minute amounts of samples, greatly reducing the consumption of test samples and other reagents, and lowering detection costs.

[0116] Preferably, the light source 4 is an ultraviolet-visible light source 4.

[0117] Preferably, the microfluidic system further includes a temperature control device (not shown in the figure), on which the microfluidic chip 1 is placed, and the temperature control device is used to provide a constant temperature for the microfluidic chip 1.

[0118] Preferably, such as Figure 6 As shown, the liquid pumping device 2 includes multiple liquid pumps, each of which is connected to the liquid inlet channel 210 and injection channel 220 of the microfluidic chip 1 in a one-to-one correspondence.

[0119] The microfluidic system also includes an autosampler 6, which is connected to the inlet channel 210 for pumping in the sample to be tested; the autosampler 6 is used to switch and automatically add the sample to be tested.

[0120] Multiple liquid pumps enable individual control of reagents such as aqueous buffer, test sample, oil phase liquid, tyrosine, and tyrosinase. By controlling different pumps to provide different pumping pressures, such as adjusting the pumping pressure of the aqueous buffer and the test sample, the concentration of the test sample solution formed by the test sample and the aqueous buffer can be changed. Through the overall regulation of the control device, multiple microdroplets can be made to have a continuous concentration gradient in sequence, thereby obtaining the concentration gradient detection data of the input test sample in a single operation, with extremely high efficiency.

[0121] Preferably, the microfluidic system further includes a waste liquid collection device 7, which is connected to the sample outlet 230 of the detection area 20c of the microfluidic chip 1.

[0122] In addition, the photodetector 5 can be an optical detection instrument such as a spectrometer or spectrometer, and there are no restrictions here.

[0123] Please see Figure 7 This embodiment also provides a compound detection method based on the above-described microfluidic system, the steps of which include:

[0124] S100: Building a microfluidic system;

[0125] Specifically, the microfluidic system includes a control device, a liquid pumping device 2, a voltage amplifier 3, a light source 4, a photodetector 5, and a microfluidic chip 1. Step S100 includes:

[0126] S110: Prepare microfluidic chip 1;

[0127] S120: Connect the multiple liquid inlet channels 210 and multiple injection channels 220 of the microfluidic chip 1 to the liquid pumping device 2;

[0128] S130: Fill the microelectrode channel 30 of the microfluidic chip 1 with conductive material and electrically connect the microelectrode channel 30 to the voltage amplifier 3.

[0129] S140: Connect the first optical fiber 430 of the microfluidic chip 1 to the light source 4, and connect the second optical fiber 440 of the microfluidic chip 1 to the photodetector 5.

[0130] Specifically, the microfluidic system also includes a temperature control device, and after step S140, it further includes:

[0131] S150: After the temperature control device reaches the preset temperature, place the microfluidic chip 1 on the temperature control device;

[0132] S200: The sample to be tested, aqueous buffer solution and oil liquid are pumped into the liquid inlet channel 210 through the liquid pumping device 2, and microdroplets are generated in the generation area 20a of the microfluidic chip 1.

[0133] S300: Tyrosine and tyrosinase are pumped into injection channel 220 by liquid pumping device 2 so that tyrosine and tyrosinase react with microdroplets in reaction zone 20b of microfluidic chip 1.

[0134] S400: When the microdroplets after the reaction flow through the detection area 20c of the microfluidic chip 1, the photodetector 5 detects the absorbance of the microdroplets.

[0135] Further, step S200: the sample to be tested, aqueous buffer solution, and oil phase liquid are pumped into the liquid inlet channel 210 through the liquid pumping device 2, and microdroplets are generated in the generation area 20a of the microfluidic chip 1, specifically including:

[0136] S210: The oil phase liquid is pumped at constant pressure into the liquid inlet channel 210 by the liquid pumping device 2;

[0137] S220: The aqueous buffer solution is then pumped into the inlet channel 210 at a constant pressure using the liquid pumping device 2 at the first preset pressure.

[0138] S230: Subsequently, the sample to be tested is pumped into the liquid inlet channel 210 through the liquid pumping device 2. Within a preset time, the pumping pressure of the sample to be tested increases uniformly from 0 to the first preset pressure. At the same time, the pumping pressure of the aqueous buffer solution decreases uniformly from the first preset pressure to 0, thereby generating multiple microdroplets with a gradient increase in the concentration of the sample to be tested in the generation zone 20a.

[0139] Further, step S300: tyrosine and tyrosinase are pumped into the injection channel 220 via the liquid pumping device 2, so that tyrosine and tyrosinase react with the microdroplets in the reaction zone 20b of the microfluidic chip 1, specifically including:

[0140] Voltage amplifier 3 is turned on to apply voltage to microelectrode channel 30, which can generate an electric field in reaction zone 20b. The electric field provides an electric force for injecting tyrosine and tyrosinase into injection channel 220.

[0141] Simultaneously, the liquid pumping device 2 pumps an equal amount of tyrosine and tyrosinase into the injection channel 220 at a constant pressure of the second preset pressure. Under the action of the electric field force and the second preset pressure, the tyrosine and tyrosinase are injected into the microdroplet, so that the tyrosine and tyrosinase react with the microdroplet in the reaction zone 20b of the microfluidic chip 1.

[0142] Furthermore, the microfluidic system also includes a waste liquid collection device 7 connected to the sample outlet 230 and an automatic sampler 6 connected to the liquid pump device 2. Step S400: When the reacted microdroplets flow through the detection area 20c of the microfluidic chip 1, after the photodetector 5 detects the absorbance of the microdroplets, the system further includes the following step:

[0143] S510: The microdroplets after the reaction are discharged to the waste liquid collection device 7 through the sample outlet 230 of the detection zone 20c;

[0144] S520: Stop pumping the sample to be tested, turn off the voltage amplifier 3, stop applying voltage to the microelectrode channel 30, and adjust the inlet pressure of the injection channel 220 to 0 through the liquid pumping device 2;

[0145] At the same time, the aqueous buffer solution is pumped into the inlet channel 210 by the liquid pumping device 2. Within a preset time, the pumping pressure of the aqueous buffer solution increases from 0 to the first preset pressure at a constant speed.

[0146] S530: If a new sample needs to be tested, the new sample is switched and added to the liquid pumping device through the automatic sample introduction device 6, and then the cycle is repeated from step S200.

[0147] If no new sample needs to be tested, the test of the sample is completed. The test results are output through the control device, and the pumping of the aqueous buffer solution is stopped, thus completing the test of the sample.

[0148] By implementing steps S510 to S530, the main channel 20 of the microfluidic chip 1 can be automatically cleaned with an aqueous buffer solution after detection, and new samples to be tested can be automatically introduced through the automatic sample introduction device 6, thus achieving a highly efficient and automated detection process.

[0149] This embodiment also discloses the application of the method described above in the detection of cosmetic efficacy.

[0150] It should be noted that the various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the method embodiments and application embodiments, since they are implemented based on the structure of the product class embodiments, some descriptions of the product structure are omitted; relevant details can be found in the descriptions of the product class embodiments.

[0151] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting compounds in a microfluidic system, characterized in that, The microfluidic system includes a control device, a liquid pumping device, a voltage amplifier, a light source, a photodetector, and a microfluidic chip. The microfluidic chip includes a substrate, a main channel, and a detection device; the main channel is disposed on the substrate and includes a generation zone, a reaction zone, and a detection zone connected in sequence; the generation zone is connected to multiple liquid inlet channels, and at least one of the liquid inlet channels has a sample inlet for injecting the sample to be tested into the generation zone; The reaction zone is connected to multiple injection channels, each of which is used to inject tyrosine and tyrosinase respectively. The sample to be tested, the tyrosine, and the tyrosinase can be mixed and reacted in the reaction zone and then flow to the detection zone. The detection zone is provided with a sample outlet. The detection device is used to detect the absorbance of microdroplets flowing through the detection zone. The generation area includes a first generation channel and a second generation channel; At least a portion of the liquid inlet channels are respectively provided with an aqueous phase inlet and an oil phase inlet, the aqueous phase inlet and the oil phase inlet being used to inject an aqueous buffer solution and an oil phase liquid, respectively; The first end of the first generation channel is connected to the aqueous phase inlet and the sample inlet to be tested, and the second end of the first generation channel is connected to the oil phase inlet and the second generation channel; The microfluidic chip also includes a microelectrode channel, which is capable of generating an electric field in the reaction region. The electric field is used to provide an electric force for injecting tyrosine and tyrosinase into the reaction region. The detection device includes a first optical fiber and a second optical fiber; the first optical fiber and the second optical fiber are disposed on the substrate, the first optical fiber is used to connect to a light source to output test light, the test light passes through the detection area in one direction, and the second optical fiber is used to receive the test light after it passes through the detection area and is connected to a photodetector. The control device is connected to the liquid pumping device, the voltage amplifier, the light source, and the photodetector. The liquid pumping device is connected to multiple inlet channels and injection channels of the microfluidic chip. The liquid pumping device is used to pump the sample to be tested, aqueous buffer solution, and oil phase liquid into each of the inlet channels, respectively. The liquid pumping device is also used to pump tyrosine and tyrosinase into each of the injection channels, respectively. The voltage amplifier is electrically connected to the voltage signal port and ground port of the microelectrode channel. The light source is connected to the first optical fiber of the microfluidic chip. The light source is used to output test light into the first optical fiber. The test light passes through the detection area of ​​the microfluidic chip in one direction. The photodetector is connected to the second optical fiber of the microfluidic chip. The second optical fiber receives the test light after it passes through the detection area. The photodetector is used to detect the absorbance of the microdroplets flowing through the detection area. The steps of the compound detection method of the microfluidic system include: The liquid pumping device pumps the sample to be tested, aqueous buffer solution and oil liquid into the liquid inlet channel, and generates microdroplets in the generation area of ​​the microfluidic chip. Tyrosine and tyrosinase are pumped into the injection channel via the liquid pumping device, so that the tyrosine and the tyrosinase react with the microdroplets in the reaction area of ​​the microfluidic chip. When the microdroplets after the reaction flow through the detection area of ​​the microfluidic chip, the photodetector detects the absorbance of the microdroplets.

2. The method according to claim 1, characterized in that, Before the step of pumping the sample to be tested, aqueous buffer solution, and oil phase liquid into the liquid inlet channel through the liquid pumping device, and generating microdroplets in the generation area of ​​the microfluidic chip, the method further includes: Prepare microfluidic chips; The multiple inlet channels and multiple injection channels of the microfluidic chip are connected to a liquid pumping device; The microelectrode channels of the microfluidic chip are electrically connected to the voltage amplifier; The first optical fiber of the microfluidic chip is connected to the light source, and the second optical fiber of the microfluidic chip is connected to the photodetector.

3. The method according to claim 1, characterized in that, The process of pumping the sample to be tested, aqueous buffer solution, and oil phase liquid into the inlet channel via the liquid pumping device, and generating microdroplets in the generation area of ​​the microfluidic chip, specifically includes: The oil phase liquid is pumped at constant pressure into the inlet channel by the liquid pumping device. The aqueous buffer solution is then pumped into the inlet channel at a constant pressure using the liquid pumping device at a first preset pressure. The sample to be tested is pumped into the inlet channel by the liquid pumping device. Within a preset time, the pumping pressure of the sample to be tested increases uniformly from 0 to the first preset pressure. At the same time, the pumping pressure of the aqueous buffer solution decreases uniformly from the first preset pressure to 0. In this way, multiple microdroplets with a gradient increase in the concentration of the sample to be tested are formed in the generation zone.

4. The method according to claim 1, characterized in that, The step of pumping tyrosine and tyrosinase into the injection channel via the liquid pumping device, so that the tyrosine and the tyrosinase react with the microdroplets in the reaction region of the microfluidic chip, specifically includes: The voltage amplifier is turned on to apply a voltage to the microelectrode channel, which can form an electric field in the reaction zone. The electric field provides an electric force for injecting tyrosine and tyrosinase into the injection channel. Simultaneously, the liquid pumping device pumps an equal amount of tyrosine and tyrosinase into the injection channel at a constant pressure of the second preset pressure. Under the action of the electric field force and the second preset pressure, the tyrosine and tyrosinase are injected into the microdroplet, so that the tyrosine and the tyrosinase react with the microdroplet in the reaction zone of the microfluidic chip.

5. The method according to claim 1, characterized in that, The cross-sectional area of ​​the first generation channel is smaller than the cross-sectional area of ​​the second generation channel.

6. The method according to claim 1, characterized in that, The detection device includes two micro-fiber channels, which are symmetrically arranged on both sides of the detection area. The first optical fiber and the second optical fiber are respectively fixed in each of the micro-fiber channels.

7. The application of the method as described in any one of claims 1 to 6 in the efficacy testing of cosmetics.

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