Micro-fluidic chip for realizing on-line detection of Raman, fluorescence and absorbance

Abstract

The invention relates to the technical field of microfluidics, in particular to a micro-fluidic chip for realizing on-line detection of Raman, fluorescence and absorbance, which comprises a first micro-droplet generation channel, a second micro-droplet generation channel and a micro-droplet fusion channel, the first micro-droplet generation channel and the second micro-droplet generation channel are symmetrically arranged, and channel outlets of the first micro-droplet generation channel and the second micro-droplet generation channel are connected and communicated with a channel inlet of the micro-droplet fusion channel; the first micro-droplet generation channel comprises a first micro-droplet generation area, a first absorbance detection area and a first fluorescence detection area which are arranged in sequence, and the second micro-droplet generation channel comprises a second micro-droplet generation area, a second absorbance detection area and a second fluorescence detection area which are arranged in sequence; the micro-droplet fusion channel comprises a buffer region and a Raman detection region which are sequentially arranged along the flowing direction of micro-droplets. Synchronous movement, fusion and capture of liquid drops can be achieved, so that the liquid drop fusion efficiency is improved, the capture process is simplified, and the device is suitable for online detection and analysis of high-throughput microorganisms.

Description

Technical Field

[0001] The invention relates to the technical field of microfluidics, and in particular to a microfluidics chip for realizing online detection of Raman, fluorescence and absorbance. Background Art

[0002] With the rapid development of microfluidics, droplet microfluidics has attracted more and more attention due to its wide applications in biological analysis, chemical reactions and medical diagnosis. Its core lies in the precise control and operation of liquid samples through tiny fluid channels. As an important form of microfluidics, droplet microfluidics can effectively process trace samples and show great potential in biological analysis, drug screening and other aspects.

[0003] The generation, fusion and capture of droplets are key operating steps in microfluidic chips, which affect the sample processing efficiency and detection sensitivity. However, the existing droplet fusion and capture technology still has some shortcomings, such as low droplet fusion efficiency, complex capture process, and high requirements for sample fluidity, making it difficult to achieve efficient fusion and capture of droplets from different samples. These problems severely limit the application of droplet microfluidics technology in high-throughput microbial detection, so a new type of microfluidic chip is urgently needed to improve detection efficiency and accuracy. Summary of the invention

[0004] The purpose of the present invention is to provide a microfluidic chip for realizing online detection of Raman, fluorescence and absorbance, which can realize the synchronous movement, fusion and capture of droplets, thereby improving the droplet fusion efficiency, simplifying the capture process, and is suitable for online detection and analysis of high-throughput microorganisms.

[0005] The technical solution adopted by the present invention is as follows: A microfluidic chip for realizing online detection of Raman, fluorescence and absorbance comprises a first microdroplet generation channel, a second microdroplet generation channel and a microdroplet fusion channel; one of the first microdroplet generation channel and the second microdroplet generation channel is used to generate sample microdroplets, and the other is used to generate Raman enhanced particle microdroplets; the first microdroplet generation channel and the second microdroplet generation channel are symmetrically arranged, and the channel outlets of the two are connected and communicated with the channel inlet of the microdroplet fusion channel; the first microdroplet generation channel comprises a first microdroplet generation area, a first absorbance detection area and a first fluorescence detection area sequentially arranged along the flow direction of the medium, the second microdroplet generation channel comprises a second microdroplet generation area, a second absorbance detection area and a second fluorescence detection area sequentially arranged along the flow direction of the medium, and the microdroplet fusion channel comprises a buffer area and a Raman detection area sequentially arranged along the flow direction of the microdroplet.

[0006] Furthermore, the first micro-droplet generation area includes a sample channel and a first oil phase channel, the sample channel carries the sample to be detected, the first oil phase channel carries the first oil phase, and the sample channel and the first oil phase channel converge and communicate with the first absorbance detection area.

[0007] Furthermore, the sample channel and the first oil phase channel are in a T-shaped cross-flow structure, a Y-shaped cross-flow structure or a cross-shaped flow focusing structure on the microfluidic chip.

[0008] Furthermore, the second micro-droplet generation area includes a Raman enhanced particle channel and a second oil phase channel, the Raman enhanced particle channel has Raman enhanced particles flowing therein, the second oil phase channel has a second oil phase flowing therein, and the Raman enhanced particle channel and the second oil phase channel converge and are connected to the second absorbance detection area.

[0009] Furthermore, the Raman enhanced particle channel and the second oil phase channel are in a T-shaped cross-flow structure, a Y-shaped cross-flow structure or a cross-shaped flow focusing structure on the microfluidic chip.

[0010] Furthermore, the buffer zone is a planar curved disc structure.

[0011] Furthermore, it also includes an optical fiber, the light output end of the optical fiber acts on the first absorbance detection area and the second absorbance detection area, the channels at the corresponding positions of the first absorbance detection area and the second absorbance detection area are droplet compression channels, and the detection sensitivity is improved by increasing the optical path.

[0012] Furthermore, the first fluorescence detection area, the second fluorescence detection area and the Raman detection area achieve micro-droplet capture and retention through cross-sectional expansion.

[0013] Furthermore, the Raman detection area is provided with a fused micro-droplet recognition element, and Raman detection is performed in response to the micro-droplet recognition element recognizing the fused micro-droplet.

[0014] The present invention has the following unexpected beneficial effects: 1. In the present invention, one of the first micro-droplet generation channel and the second micro-droplet generation channel is used to generate sample micro-droplets, and the other is used to generate Raman-enhanced particle micro-droplets; and the first micro-droplet generation channel and the second micro-droplet generation channel are symmetrically arranged, and the channel outlets of the two are connected and connected to the channel inlet of the micro-droplet fusion channel, so that the microfluidic chip can realize the synchronous flow and fusion of sample micro-droplets and Raman-enhanced particle micro-droplets under the action of symmetrical structure and symmetrical flow, meeting the research requirements on droplet fusion characteristics.

[0015] 2. The present invention transforms the channel through the principle of fluid dynamics, that is, the first fluorescence detection area, the second fluorescence detection area and the Raman detection area achieve micro-droplet capture and retention through cross-sectional expansion, which is particularly suitable for high-throughput online quantitative and qualitative analysis of microorganisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is one of the structural schematic diagrams of the microfluidic chip for online detection of Raman, fluorescence and absorbance described in the embodiments of the present application; Figure 2 This is the second structural schematic diagram of the microfluidic chip for online detection of Raman, fluorescence and absorbance described in the embodiments of the present application.

[0017] In the figure, 1 is the first micro-droplet generation channel, 11 is the first micro-droplet generation area, 111 is the first oil phase channel, 112 is the sample channel, 12 is the first absorbance detection area, and 13 is the first fluorescence detection area; 2—second micro-droplet generation channel, 21—second micro-droplet generation area, 211—second oil phase channel, 212—Raman enhanced particle channel, 22—second absorbance detection area, 23—second fluorescence detection area; 3—micro-droplet fusion channel, 31—buffer zone, 32—Raman detection zone, 33—droplet outlet; 4—Optical fiber. DETAILED DESCRIPTION

[0018] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0019] In one embodiment, see Figure 1As shown, the present invention provides a microfluidic chip for realizing online detection of Raman, fluorescence and absorbance, comprising a first microdroplet generation channel 1, a second microdroplet generation channel 2 and a microdroplet fusion channel 3; one of the first microdroplet generation channel 1 and the second microdroplet generation channel 2 is used to generate sample microdroplets, and the other is used to generate Raman enhanced particle microdroplets; the first microdroplet generation channel 1 and the second microdroplet generation channel 2 are symmetrically arranged, and the channel outlets of the two are connected and connected to the channel inlet of the microdroplet fusion channel 3; the first microdroplet generation channel 1 comprises a first microdroplet generation area 11, a first absorbance detection area 12 and a first fluorescence detection area 13 arranged in sequence along the flow direction of the medium, the second microdroplet generation channel 2 comprises a second microdroplet generation area 21, a second absorbance detection area 22 and a second fluorescence detection area 23 arranged in sequence along the flow direction of the medium, and the microdroplet fusion channel 3 comprises a buffer area 31 and a Raman detection area 32 arranged in sequence along the flow direction of the microdroplets.

[0020] The first micro-droplet generation channel 1 and the second micro-droplet generation channel 2 allow the independent generation of sample micro-droplets and Raman-enhanced particle micro-droplets. This modular design not only improves the flexibility of the microfluidic chip, but also allows users to adjust the generation ratio and rate of the two micro-droplets according to experimental requirements. And through the symmetrical arrangement, the synchronization and stability of the sample micro-droplets and the Raman-enhanced particle micro-droplets during the flow process are ensured, providing a good foundation for the subsequent fusion and detection process.

[0021] The absorbance detection areas 12 and 22 are arranged after the micro-droplet generation channels 11 and 12, that is, the absorbance detection is performed immediately after the micro-droplets are generated, which can obtain the initial optical properties of the micro-droplets in real time and provide important reference for subsequent analysis.

[0022] The arrangement of the fluorescence detection areas 13 and 23 enables the microfluidic chip to simultaneously detect fluorescent markers in the sample, further enriching the detection means and improving the comprehensiveness and accuracy of the detection.

[0023] The micro-droplet fusion channel 3 effectively slows down the flow rate of the micro-droplets by designing a buffer zone 31, and promotes the full fusion of the sample micro-droplets and the Raman enhanced particle micro-droplets. This fusion not only enhances the Raman signal, but also makes the detection more sensitive and reliable.

[0024] When the fused micro-droplets enter the Raman detection area 32, the Raman spectroscopy technique is used to analyze them, thereby obtaining vibration spectrum information of the sample molecules, providing strong support for qualitative and quantitative analysis of the substance.

[0025] The present invention integrates multiple steps such as sample preparation, microdroplet generation, fusion, and detection on a microfluidic chip, greatly simplifying the experimental process and reducing sample consumption and contamination risks. The microfluidic chip can achieve synchronous flow and fusion of sample microdroplets and Raman enhanced particle microdroplets under the action of symmetrical structure and symmetrical flow. By controlling the fluid flow in the microfluidic chip, the automated operation of the experiment is realized, and the repeatability and stability of the experiment are improved.

[0026] The present invention can be widely used in many fields such as biomedicine, environmental monitoring, food safety, and drug screening, providing researchers with an efficient and convenient multi-parameter detection platform.

[0027] In summary, the microfluidic chip of the present invention provides a new tool and means for scientific research through its unique design and versatility, and has important theoretical significance and application value.

[0028] In a preferred embodiment, see Figure 1 As shown, the first micro-droplet generation area 11 includes a first oil phase channel 111 and a sample channel 112, and the sample channel 112 is connected to the sample to be detected. The sample can be in liquid form and contains biological, chemical or material substances that need to be analyzed by Raman, fluorescence or absorbance. The design of the sample channel needs to ensure that the sample can flow smoothly and continuously to avoid contamination or denaturation during the transportation process. The first oil phase channel 111 is connected to the first oil phase, and its main function is to wrap the sample in the oil phase through the principle of immiscibility when it intersects with the sample channel to form dispersed micro-droplets. This oil-in-water micro-droplet structure helps to protect the sample and prevent it from being contaminated or disturbed during subsequent processing. At the same time, the formation of micro-droplets also facilitates independent analysis and detection of a single sample.

[0029] When the first oil phase channel 111 and the sample channel 112 intersect, the sample will be wrapped by the oil phase and cut into tiny droplets due to the immiscibility between the two. These micro droplets then enter the first absorbance detection area 12 for preliminary optical property detection. This arrangement cleverly utilizes the microchannel structure and fluid dynamics principles of the microfluidic chip to achieve automated processing and detection of samples.

[0030] The present invention can quickly generate a large number of microdroplets in a very small volume through microfluidic chip technology, greatly improving the efficiency of sample processing. The formation and detection process of microdroplets are all carried out on a micrometer scale, ensuring the accuracy and sensitivity of the analysis. The entire sample processing, microdroplet generation and detection process can be automated through the microfluidic chip, reducing the interference and error of human factors. Combined with subsequent fluorescence detection and Raman detection area 32, the microfluidic chip can simultaneously realize the analysis and detection of multiple optical properties, providing more comprehensive and in-depth information for scientific research.

[0031] In summary, the design of the first micro-droplet generation area in the preferred embodiment reflects the highly integrated and intelligent characteristics of the microfluidic chip in sample processing and detection, and provides an efficient, accurate and automated analysis platform for scientific research.

[0032] Further, see Figure 1 As shown, the first oil phase channel 111 and the sample channel 112 form a cross-shaped flow focusing structure on the microfluidic chip. At the intersection of the cross-shaped structure, the oil phase fluid in the first oil phase channel 111 meets the sample fluid in the sample channel 112. Due to the immiscibility between the two, when they meet at an appropriate flow rate and flow ratio, the oil phase fluid wraps the sample fluid and cuts it into tiny droplets.

[0033] Near the intersection, the geometry and size of the oil phase channel and the sample channel are carefully designed to ensure that the sample fluid is focused into a narrow area during the flow process, which is conducive to the formation of microdroplets. This flow focusing effect improves the efficiency and stability of microdroplet generation. And as the oil phase and sample fluid continue to flow, microdroplets are continuously generated at the intersection and flow along the channels of the microfluidic chip to the subsequent detection area.

[0034] The cross-shaped flow focusing structure has the following beneficial effects.

[0035] 1. Efficient generation: The cross-shaped flow focusing structure can ensure that microdroplets are generated quickly and continuously on the chip, improving the efficiency of sample processing.

[0036] 2. Stable and controllable: By adjusting the flow rate and flow ratio of the oil phase and sample fluid and the geometric dimensions of the channel, the size, shape and generation frequency of the microdroplets can be precisely controlled to achieve stable and controllable microdroplet generation.

[0037] 3. Reduce pollution: Since the microdroplets are wrapped by the oil phase, a relatively closed environment is formed, which helps to reduce contamination and interference during the generation and transmission of samples.

[0038] 4. Integrated design: Combined with the subsequent absorbance, fluorescence and Raman detection areas, the design of the cross-shaped flow focusing structure makes the entire microfluidic chip more compact and integrated, facilitating experimental operation and data collection.

[0039] In summary, the application of the cross-shaped flow focusing structure in the first oil phase channel 111 and the sample channel 112 not only improves the efficiency and stability of microdroplet generation, but also provides strong support for the realization of multi-parameter online detection. This design reflects the unique advantages and broad application prospects of microfluidic chip technology in sample processing and detection.

[0040] It should also be noted that the first oil phase channel 111 and the sample channel 112 can also be in a T-shaped cross-flow structure or a Y-shaped cross-flow structure on the microfluidic chip.

[0041] See also Figure 2 As shown, in the T-shaped cross-flow structure, the first oil phase channel 111 is usually used as the main channel, and the sample channel 112 is used as a branch channel to intersect it vertically. When the oil phase flows from the branch channel into the main channel, it will produce a cross-flow effect with the sample flow to be detected at the intersection, thereby wrapping the sample in the oil phase to form microdroplets. This structure is simple and easy to make, and is suitable for generating microdroplets with relatively uniform size distribution.

[0042] The Y-shaped cross-flow structure is similar to the T-shaped structure, but the difference is that the branch intersects with the main road in the form of a Y-shaped fork. This structure can control the intersection of the oil phase sample flow by adjusting the position and angle of the bifurcation point, thereby achieving more precise control of microdroplet generation. The Y-shaped structure may have better performance in terms of consistency of microdroplet size and shape.

[0043] In a preferred embodiment, see Figure 1 As shown, the second micro-droplet generating area 21 includes a second oil phase channel 211 and a Raman enhanced particle channel 212, the second oil phase channel 211 is connected with the second oil phase, the Raman enhanced particle channel 212 is connected with Raman enhanced particles, and the second oil phase channel 211 and the Raman enhanced particle channel 212 are connected with the second absorbance detection area 22 after converging.

[0044] The Raman enhanced particle channel 212 is specifically used to transport Raman enhanced particles. Raman enhanced particles are a substance that can significantly enhance Raman signals, usually have a large specific surface area and a special surface structure, and can strongly interact with sample molecules. The design of the Raman enhanced particle channel 212 needs to ensure that the particles can flow smoothly and continuously, and mix with the second oil phase to form micro droplets when necessary.

[0045] The second oil phase channel 211 is similar to the first oil phase channel 111, and a second oil phase is passed through the second oil phase channel 211. This oil phase is also used to wrap the Raman enhancement particles to form oil-in-particle microdroplets. The oil phase should be selected to ensure that it is immiscible with the Raman enhancement particles and can stably wrap the particles to prevent them from aggregating or precipitating during subsequent processing.

[0046] The second oil phase channel 211 and the Raman enhanced particle channel 212 intersect in a cross shape or other appropriate structure on the microfluidic chip. At the intersection, the oil phase wraps the Raman enhanced particles and cuts them into tiny droplets. These micro droplets then enter the second absorbance detection area 22 for preliminary optical property detection. By adjusting the size, flow rate and flow ratio of the channel, the size, shape and generation frequency of the micro droplets can be controlled.

[0047] This setting has the following advantages: 1. Enhanced Raman signal: The introduction of Raman enhanced particles can significantly improve the sensitivity of Raman detection, allowing the chip to detect sample molecules with lower concentrations.

[0048] 2. Parallel processing: The first micro-droplet generation area and the second micro-droplet generation area can work in parallel to process samples and Raman enhanced particles at the same time, thereby improving the overall processing efficiency of the chip.

[0049] 3. Multifunctional integration: Combined with subsequent fluorescence detection and Raman detection areas, the chip can realize comprehensive analysis of the various optical properties of the sample, providing more comprehensive and in-depth information for scientific research.

[0050] 4. Automated operation: The entire process of microdroplet generation and detection can be automated through microfluidic chips, reducing interference and errors caused by human factors.

[0051] In summary, the design of the second micro-droplet generation area 21 enables the microfluidic chip to efficiently generate micro-droplets containing Raman enhanced particles, and subsequently fuse and detect with sample micro-droplets. This design not only improves the sensitivity of Raman detection, but also realizes the integration and automation of multiple analysis technologies.

[0052] Furthermore, the second oil phase channel 211 and the Raman enhanced particle channel 212 are in a T-shaped cross-flow structure, a Y-shaped cross-flow structure or a cross-shaped flow focusing structure on the microfluidic chip.

[0053] When choosing a specific intersection structure, the following factors need to be considered: 1. Experimental requirements: Choose the appropriate structure according to the specific requirements of the experiment. For example, if you need to generate microdroplets with uniform size distribution, a T-shaped or Y-shaped cross-flow structure may be more suitable; if higher stability and controllability are required, a cross-shaped flow focusing structure may be more preferred.

[0054] 2. Difficulty of chip production: The difficulty of production of different structures may vary. When choosing, you need to consider the production capacity and equipment conditions of the laboratory.

[0055] 3. Ease of operation: The complexity of the structure may affect the ease of operation. Choosing a simple and easy-to-operate structure can reduce the difficulty and cost of the experiment.

[0056] In summary, the intersection structure of the second oil phase channel 211 and the Raman enhanced particle channel 212 on the microfluidic chip has an important influence on the generation and subsequent detection of microdroplets. Selecting a suitable structure according to experimental requirements and experimental conditions is the key to ensure the success of the experiment.

[0057] In a preferred embodiment, see Figure 1 As shown, the buffer zone 31 is a planar curved disc structure.

[0058] The buffer zone 31 plays two key roles in the microfluidic chip: first, it regulates the speed and stability of the fluid flow to ensure the smooth progress of the subsequent processing steps; second, it serves as a reaction or mixing chamber to promote sufficient mixing or reaction between different fluids.

[0059] The planar curved disk structure can effectively reduce the flow rate of the fluid by increasing the flow path length of the fluid in the buffer zone, thereby providing sufficient time for the particles, molecules or reagents in the fluid to fully mix, react or diffuse.

[0060] The curved disk structure helps reduce turbulence and eddy currents in the fluid flow process and improves the stability of the fluid flow, which is particularly important for microfluidic experiments that require precise control of fluid behavior.

[0061] In the curved disk structure, the contact area between different fluids increases, which is conducive to the full mixing between them. For experiments that require mixing multiple reagents or samples, this design can significantly improve the mixing efficiency.

[0062] Although the disc structure occupies a certain area on the plane, it can achieve long-distance fluid flow in a limited space, thus saving vertical space on the chip. This is an important advantage for the design of microfluidic chips with high integration requirements.

[0063] The planar curved disc structure can be easily integrated with other microfluidic components (such as microchannels, microvalves, micropumps, etc.) to form a fully functional microfluidic system.

[0064] In practical applications, the planar curved disc structure buffer can be used in a variety of microfluidic experiments, such as: Sample pretreatment: Before sending the sample to the detection area, the sample is pretreated by dilution, filtration or enrichment through a buffer.

[0065] Reagent mixing: In chemical reactions or biological experiments, multiple reagents are thoroughly mixed in a buffer to ensure the smooth progress of the reaction.

[0066] Product Collection: After the reaction is complete, the product is introduced into a buffer for collection and storage for subsequent analysis or further processing.

[0067] In summary, the planar curved disc-structured buffer 31 has important application value in the design of microfluidic chips. It can improve the stability and mixing efficiency of fluid flow and provide reliable protection for microfluidic experiments.

[0068] In a preferred embodiment, see Figure 1 As shown, it also includes an optical fiber 4, the light output end of the optical fiber 4 acts on the first absorbance detection area 12 and the second absorbance detection area 22, and the channels at the corresponding positions of the first absorbance detection area 12 and the second absorbance detection area 22 are droplet compression channels, which improve the detection sensitivity by increasing the optical path.

[0069] The optical fiber 4 is mainly used to transmit light in the microfluidic chip, and its light output end directly acts on the first absorbance detection area 12 and the second absorbance detection area 22. This arrangement allows the light to directly irradiate the sample in the droplet compression channel, thereby performing absorbance detection.

[0070] The channels at the corresponding positions of the first absorbance detection area 12 and the second absorbance detection area 22 are designed as droplet compression channels, the main purpose of which is to increase the optical path by compressing the droplets, thereby improving the detection sensitivity. When the droplets flow in the compression channel, their volume decreases and the optical path increases, so that the interaction time between light and the sample is prolonged, thereby improving the accuracy of the detection.

[0071] The droplets are squeezed in the compression channel, and their volume decreases, but the path of light through the droplets (i.e., the optical path) increases. This increases the opportunity for light to interact with sample molecules, thereby improving the sensitivity of detection. Due to the increase in the optical path, the signal generated after the light is absorbed by the sample is also correspondingly enhanced. This allows even weak absorbance changes to be detected in low-concentration samples. The design of the droplet compression channel also helps to reduce interference from background light. By precisely controlling the irradiation position and angle of the light, light scattering and reflection in non-target areas can be minimized, thereby improving the signal-to-noise ratio of the detection signal.

[0072] This microfluidic chip design that combines optical fiber and droplet compression channels has broad application prospects in the fields of biochemistry, drug analysis, environmental monitoring, etc. For example, in the process of drug screening, the chip can be used to quickly and efficiently detect the interaction between drugs and biological molecules; in environmental monitoring, it can realize the rapid identification and quantitative analysis of pollutants in water, air and other samples.

[0073] Directly introducing light into the droplet compression channel of a microfluidic chip through an optical fiber and using droplet compression to increase the optical path and improve detection sensitivity is an innovative and effective microfluidic chip design solution. This solution can not only improve the accuracy and sensitivity of detection, but also has broad application prospects and important practical value.

[0074] In a preferred embodiment, in the design of the microfluidic chip, in order to achieve the capture and retention of the microdroplets in the first fluorescence detection area 13, the second fluorescence detection area 23 and the Raman detection area 32, see Figure 1 As shown in FIG. 1 , the use of a cross-sectional expansion structure is an effective method. This design can ensure that the microdroplets stay stably in the detection area, thereby allowing sufficient time for optical detection and improving the accuracy and sensitivity of the detection.

[0075] The cross-sectional expansion structure sets a gradually increasing channel width or height in front of the detection area, so that the flow rate of the fluid gradually slows down when passing through the area. When the micro-droplets enter the cross-sectional expansion area, due to the increase in the channel cross-section, their forward kinetic energy is dispersed, resulting in a significant decrease in the speed of the micro-droplets, and finally staying in the detection area.

[0076] Capture dwell has the following advantages: 1. Stable detection: The stable stay of micro-droplets in the detection area provides a stable environment for optical detection, reduces signal fluctuations caused by the movement of micro-droplets, and improves the accuracy of detection.

[0077] 2. Extend the detection time: By capturing and retaining, the residence time of the microdroplets in the detection area can be extended, so that the detector can collect more signals and improve the sensitivity of the detection.

[0078] 3. Easy to integrate: The cross-sectional expansion structure is relatively simple and easy to integrate with other microfluidic components to form a fully functional microfluidic system.

[0079] In the first fluorescence detection area 13 and the second fluorescence detection area 23, the cross-sectional expansion structure can ensure that the fluorescently labeled microdroplets stay stably in the detection area, so that the fluorescence detector can accurately capture the fluorescence signal for analyzing specific components or reaction products in the sample.

[0080] In the Raman detection area 32, the cross-sectional expansion can also capture the micro-droplets containing Raman enhanced particles and make them stay stably at the detection point. The laser beam is focused on the micro-droplets to stimulate Raman scattering. By collecting and analyzing the Raman spectrum, the vibration and rotation information of the sample molecules can be obtained, and then the chemical structure and composition of the sample can be inferred.

[0081] It should be noted that the proportion of cross-sectional expansion should be moderate, ensuring that the microdroplets can stay stably while avoiding excessive expansion that causes fluid reflux or unnecessary eddy currents. The channel surface of the detection area should be properly treated to reduce the interaction between the microdroplets and the channel wall and prevent the microdroplets from adhering or deforming. By precisely controlling the flow rate and flow rate of the fluid, it is ensured that the microdroplets can smoothly enter and stay in the detection area.

[0082] In summary, capturing and retaining microdroplets in the first fluorescence detection area 12, the second fluorescence detection area 22 and the Raman detection area 32 by cross-sectional expansion is an effective microfluidic chip design strategy, which can significantly improve the accuracy and sensitivity of optical detection.

[0083] In a preferred embodiment, in order to further improve the accuracy and efficiency of Raman detection, the introduction of a fused micro-droplet recognition element is an innovative and practical solution, that is, a fused micro-droplet recognition element is arranged in the Raman detection area 32, and Raman detection is performed in response to the micro-droplet recognition element recognizing a fused micro-droplet. This design can ensure that Raman detection is performed only when a fused micro-droplet is recognized, thereby avoiding unnecessary detection operations and improving the automation and intelligence level of the detection process.

[0084] The fused microdroplet recognition element is a device that can detect and identify fused microdroplets in a microfluidic chip. It is integrated near the Raman detection area and senses the fusion event of microdroplets by optical, electrical or mechanical means. When two or more microdroplets containing different components fuse under specific conditions, the recognition element will send a signal to trigger the subsequent Raman detection process.

[0085] Microdroplet fusion: In a specific area of ​​the microfluidic chip (such as the fusion area 31), the flow rate, flow rate and channel structure of the fluid are precisely controlled to allow microdroplets containing different components to fuse. These microdroplets may contain samples, reaction reagents or Raman enhanced particles, etc.

[0086] Recognition element response: When the fused microdroplet passes through the fused microdroplet recognition element, the element detects the fusion characteristics of the microdroplet (such as size change, optical property change, etc.) and sends out a recognition signal.

[0087] Triggering Raman detection: The identification signal is transmitted to the control system, which determines whether Raman detection needs to be performed according to the preset program. If it is confirmed that it is a fused microdroplet and meets the detection conditions, the control system will start the Raman detector and perform Raman spectroscopy analysis on the fused microdroplet.

[0088] Data analysis: The spectral data collected by the Raman detector will be transmitted to the data analysis system for processing and analysis to obtain the vibration and rotation information of the sample molecules, and then infer the chemical structure and composition of the sample.

[0089] The present invention can ensure that the detection object is the expected fusion product by identifying fused microdroplets and performing Raman detection, avoiding interference from non-target microdroplets. Since detection is performed only when fused microdroplets are identified, unnecessary detection operations are reduced, and the automation and intelligence level of the detection process is improved. The introduction of fused microdroplet recognition elements makes the microfluidic chip system more flexible, and the detection strategy and process can be adjusted according to experimental requirements.

[0090] This microfluidic chip design that combines the microdroplet recognition element and the Raman detection area has broad application prospects in the fields of biochemistry, drug analysis, environmental monitoring, etc. It can not only be used to study the molecular interactions and reaction mechanisms in complex biological samples, but also can be used to quickly screen and identify target molecules such as drugs and pollutants. With the continuous advancement of technology and the reduction of costs, this microfluidic chip system is expected to be more widely used and promoted in the future.

[0091] The above-mentioned embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above-mentioned embodiments. Any other changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A microfluidic chip for online detection of Raman, fluorescence and absorbance, characterized in that: It comprises a first micro-droplet generation channel (1), a second micro-droplet generation channel (2) and a micro-droplet fusion channel (3); One of the first micro-droplet generation channel (1) and the second micro-droplet generation channel (2) is used to generate sample micro-droplets, and the other is used to generate Raman enhanced particle micro-droplets; The first micro-droplet generation channel (1) and the second micro-droplet generation channel (2) are symmetrically arranged, and the channel outlets of the two are connected and communicated with the channel inlet of the micro-droplet fusion channel (3); The first micro-droplet generation channel (1) comprises a first micro-droplet generation area (11), a first absorbance detection area (12) and a first fluorescence detection area (13) which are sequentially arranged along the flow direction of the medium; the second micro-droplet generation channel (2) comprises a second micro-droplet generation area (21), a second absorbance detection area (22) and a second fluorescence detection area (23) which are sequentially arranged along the flow direction of the medium; and the micro-droplet fusion channel (3) comprises a buffer area (31) and a Raman detection area (32) which are sequentially arranged along the flow direction of the micro-droplets.

2. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The first micro-droplet generation area (11) comprises a first oil phase channel (111) and a sample channel (112); the first oil phase channel (111) is connected to a first oil phase, the sample channel (112) is connected to a sample to be detected, and the first oil phase channel (111) and the sample channel (112) are connected to the first absorbance detection area (12) after converging.

3. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 2, characterized in that: The first oil phase channel (111) and the sample channel (112) are in a T-shaped cross-flow structure, a Y-shaped cross-flow structure or a cross-shaped flow focusing structure on the microfluidic chip.

4. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The second micro-droplet generation area (21) comprises a second oil phase channel (211) and Raman enhanced particles (212); the second oil phase channel (211) is connected to a second oil phase; the Raman enhanced particle channel (212) is connected to a Raman enhanced particle; the second oil phase channel (211) and the Raman enhanced particle channel (212) are connected to the second absorbance detection area (22) after converging.

5. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 4, characterized in that: The second oil phase channel (211) and the Raman enhanced particle channel (212) are in a T-shaped cross-flow structure, a Y-shaped cross-flow structure or a cross-shaped flow focusing structure on the microfluidic chip.

6. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The buffer zone (31) is a planar curved disc-shaped structure.

7. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: It also comprises an optical fiber (4), wherein the light output end of the optical fiber (4) acts on the positions of the first absorbance detection zone (12) and the second absorbance detection zone (22), and the channels at the corresponding positions of the first absorbance detection zone (12) and the second absorbance detection zone (22) are droplet compression channels, and the detection sensitivity is improved by increasing the optical path.

8. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The first fluorescence detection area (13), the second fluorescence detection area (23) and the Raman detection area (32) achieve micro-droplet capture and retention through cross-sectional expansion.

9. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The Raman detection area (32) is provided with a fused micro-droplet recognition element, and Raman detection is performed in response to the micro-droplet recognition element recognizing the fused micro-droplet.

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