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

Abstract

The present application relates to the technical field of microfluidics, and particularly relates to a microfluidic chip for realizing online detection of Raman, fluorescence and absorbance, comprising a first microdroplet generation channel, a second microdroplet generation channel and a microdroplet fusion channel; the first microdroplet generation channel and the second microdroplet generation channel are symmetrically arranged, 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 zone, a first absorbance detection zone and a first fluorescence detection zone which are sequentially arranged, the second microdroplet generation channel comprises a second microdroplet generation zone, a second absorbance detection zone and a second fluorescence detection zone which are sequentially arranged, and the microdroplet fusion channel comprises a buffer zone and a Raman detection zone which are sequentially arranged along the microdroplet flow direction. The present application can realize synchronous movement, fusion and capture of droplets, thereby improving the droplet fusion efficiency, simplifying the capture process and being suitable for online detection and analysis of high-throughput microorganisms.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microfluidic technology, and particularly relates to a microfluidic chip for realizing online detection of Raman, fluorescence and absorbance. BACKGROUND

[0002] With the rapid development of microfluidic technology, droplet microfluidic systems have received increasing attention due to their wide applications in biological analysis, chemical reactions and medical diagnosis. The core of the system is to achieve precise control and operation of liquid samples through micro fluid channels. As an important form of microfluidic technology, droplet microfluidic technology can effectively handle micro samples and has great potential in biological analysis and drug screening.

[0003] Droplet generation, fusion and capture are key operation steps in microfluidic chips, which affect the processing efficiency and detection sensitivity of samples. However, the existing droplet fusion and capture technology still has some deficiencies, such as low droplet fusion efficiency, complex capture process, high requirements for sample fluidity, etc., which makes it difficult to realize efficient fusion and capture of different sample droplets. These problems seriously limit the application of droplet microfluidic technology in high-throughput microbial detection, so there is an urgent need for a new type of microfluidic chip to improve detection efficiency and accuracy. SUMMARY

[0004] The purpose of the present application 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 being suitable for online detection and analysis of high-throughput microorganisms.

[0005] The technical solution adopted by the present application is as follows:

[0006] A microfluidic chip for realizing online detection of Raman, fluorescence and absorbance, comprising 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, the channel outlets of the two are connected and communicate with the channel inlet of the microdroplet fusion channel; the first microdroplet generation channel comprises a first microdroplet generation zone, a first absorbance detection zone and a first fluorescence detection zone arranged in sequence along the medium flow direction, the second microdroplet generation channel comprises a second microdroplet generation zone, a second absorbance detection zone and a second fluorescence detection zone arranged in sequence along the medium flow direction, and the microdroplet fusion channel comprises a buffer zone and a Raman detection zone arranged in sequence along the microdroplet flow direction.

[0007] Further, the first microdroplet generation zone comprises a sample channel and a first oil phase channel, the sample channel is communicated with a sample to be detected, and the first oil phase channel is communicated with a first oil phase; the sample channel and the first oil phase channel are communicated with the first absorbance detection zone.

[0008] Further, the sample channel and the first oil phase channel are in a T-shaped crossflow structure, a Y-shaped crossflow structure or a cross-shaped flow focusing structure on the microfluidic chip.

[0009] Further, the second microdroplet generation zone comprises a Raman-enhanced particle channel and a second oil phase channel, the Raman-enhanced particle channel is communicated with Raman-enhanced particles, and the second oil phase channel is communicated with a second oil phase; the Raman-enhanced particle channel and the second oil phase channel are communicated with the second absorbance detection zone.

[0010] Further, the Raman-enhanced particle channel and the second oil phase channel are in a T-shaped crossflow structure, a Y-shaped crossflow structure or a cross-shaped flow focusing structure on the microfluidic chip.

[0011] Further, the buffer zone is a flat and curved disc structure.

[0012] Further, the device further comprises an optical fiber, the light output end of the optical fiber is arranged at the positions of the first absorbance detection zone and the second absorbance detection zone, and the channels corresponding to the positions of the first absorbance detection zone and the second absorbance detection zone are droplet compression channels, so that the detection sensitivity is improved by increasing the optical path.

[0013] Further, the first fluorescence detection zone, the second fluorescence detection zone and the Raman detection zone achieve microdroplet capture and residence through cross-section expansion.

[0014] Further, the Raman detection zone is arranged with a fused microdroplet recognition element, and the Raman detection is performed in response to the recognition of the fused microdroplet by the microdroplet recognition element.

[0015] The present application has the following unexpected beneficial effects:

[0016] 1. One of the first microdroplet generation channel and the second microdroplet generation channel is used for generating sample microdroplets, and the other is used for generating Raman-enhanced particle microdroplets; and the first microdroplet generation channel and the second microdroplet generation channel are symmetrically arranged, the channel outlets of the two are connected and communicated with the channel inlet of the microdroplet fusion channel, so that the microfluidic chip can realize the synchronous flow and fusion of sample microdroplets and Raman-enhanced particle microdroplets under the action of symmetric structure and symmetric flow, and meet the research demand for droplet fusion characteristics.

[0017] 2, The application is suitable for high-throughput online quantitative and qualitative analysis of microorganisms by reformation of the channel according to the principle of fluid dynamics, i.e. the first fluorescence detection area, the second fluorescence detection area and the Raman detection area are expanded in section to realize microdroplet capture and residence. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is one of the structure schematic diagrams of the microfluidic chip for online detection of Raman, fluorescence and absorbance in the embodiment of the application;

[0019] Figure 2 is another of the structure schematic diagrams of the microfluidic chip for online detection of Raman, fluorescence and absorbance in the embodiment of the application.

[0020] In the figure, 1 is a first microdroplet generation channel, 11 is a first microdroplet generation area, 111 is a first oil phase channel, 112 is a sample channel, 12 is a first absorbance detection area, and 13 is a first fluorescence detection area;

[0021] 2 is a second microdroplet generation channel, 21 is a second microdroplet generation area, 211 is a second oil phase channel, 212 is a Raman enhancement particle channel, 22 is a second absorbance detection area, and 23 is a second fluorescence detection area;

[0022] 3 is a microdroplet fusion channel, 31 is a buffer area, 32 is a Raman detection area, and 33 is a droplet outlet;

[0023] 4 is an optical fiber. DETAILED DESCRIPTION

[0024] The embodiments of the application will be described below with reference to the accompanying drawings and preferred embodiments, and other advantages and effects of the application can be understood by those skilled in the art from the disclosure in the specification. The application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the application. It should be understood that the preferred embodiments are only for illustrating the application, and are not intended to limit the protection scope of the application.

[0025] In an embodiment, referring to Figure 1As shown, the present application 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 for generating sample microdroplets, and the other is used for generating Raman-enhanced particle microdroplets; the first microdroplet generation channel 1 and the second microdroplet generation channel 2 are symmetrically arranged, the channel outlets of the two are connected and communicate with the channel inlet of the microdroplet fusion channel 3; the first microdroplet generation channel 1 comprises a first microdroplet generation zone 11, a first absorbance detection zone 12 and a first fluorescence detection zone 13 arranged in sequence along the medium flow direction, the second microdroplet generation channel 2 comprises a second microdroplet generation zone 21, a second absorbance detection zone 22 and a second fluorescence detection zone 23 arranged in sequence along the medium flow direction, and the microdroplet fusion channel 3 comprises a buffer zone 31 and a Raman detection zone 32 arranged in sequence along the microdroplet flow direction.

[0026] The first microdroplet generation channel 1 and the second microdroplet generation channel 2 allow independent generation of sample microdroplets and Raman-enhanced particle microdroplets. 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 kinds of microdroplets according to experimental needs. And through symmetrical arrangement, the synchronization and stability of sample microdroplets and Raman-enhanced particle microdroplets in the flow process are ensured, which provides a good foundation for the subsequent fusion and detection process.

[0027] The absorbance detection zones 12, 22 are arranged after the microdroplet generation channels 11, 12, i.e. absorbance detection is carried out immediately after microdroplet generation, which can obtain the initial optical properties of microdroplets in real time, providing important reference for subsequent analysis.

[0028] The arrangement of the fluorescence detection zones 13, 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 detection.

[0029] The microdroplet fusion channel 3 effectively slows down the flow rate of microdroplets by designing a buffer zone 31, which promotes the full fusion of sample microdroplets and Raman-enhanced particle microdroplets. This fusion not only enhances the Raman signal, but also makes the detection more sensitive and reliable.

[0030] When the fused microdroplets enter the Raman detection zone 32, they are analyzed using Raman spectroscopy technology, which can obtain the vibrational spectral information of sample molecules, providing strong support for qualitative and quantitative analysis of substances.

[0031] The present application integrates sample preparation, microdroplet generation, fusion, detection and other steps on a microfluidic chip, greatly simplifying the experimental process, reducing sample consumption and pollution risk. The microfluidic chip can realize the synchronous flow and fusion of sample microdroplets and Raman-enhanced particle microdroplets under the action of symmetric structure and symmetric flow. By controlling the fluid flow in the microfluidic chip, the automation of the experiment is realized, and the repeatability and stability of the experiment are improved.

[0032] The present application can be widely applied to biomedical, environmental monitoring, food safety, drug screening and other fields, and provides a high-efficiency, convenient multi-parameter detection platform for researchers.

[0033] In summary, the microfluidic chip of the present application provides a new tool and means for scientific research through its unique design and multifunctionality, and has important theoretical significance and application value.

[0034] In a preferred embodiment, referring to Figure 1 As shown, the first microdroplet generation area 11 includes a first oil phase channel 111 and a sample channel 112. The sample channel 112 is connected with the sample to be detected, which can be in liquid form, containing 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, avoiding pollution or denaturation during transportation. The first oil phase channel 111 is connected with the first oil phase, which mainly functions to encapsulate the sample in the oil phase by immiscibility when it meets the sample channel, forming dispersed microdroplets. This water-in-oil microdroplet structure helps to protect the sample from pollution or interference during subsequent processing. At the same time, the formation of microdroplets also facilitates independent analysis and detection of individual samples.

[0035] When the first oil phase channel 111 and the sample channel 112 meet, the sample will be encapsulated by the oil phase and cut into small droplets due to the immiscibility between the two. These microdroplets then enter the first absorbance detection area 12 for preliminary optical property detection. In this way, the microchannel structure and fluid dynamics principle of the microfluidic chip are ingeniously utilized to realize automatic processing and detection of the sample.

[0036] The microfluidic chip technology can quickly generate a large number of microdroplets in a very small volume, greatly improving the efficiency of sample processing. The formation and detection of microdroplets are 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 human factors and errors. Combined with the 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.

[0037] In summary, the first microdroplet generation area in the preferred embodiment embodies the highly integrated and intelligent characteristics of the microfluidic chip in sample processing and detection, providing a high-efficiency, accurate and automated analysis platform for scientific research.

[0038] Further, referring to 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 intersect at an appropriate flow rate and flow ratio, the oil phase fluid will encapsulate and cut the sample fluid into tiny droplets.

[0039] 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 flow, thereby facilitating the formation of microdroplets. This flow focusing effect improves the efficiency and stability of microdroplet generation. And with the continuous flow of oil phase and sample fluid, microdroplets are continuously generated at the intersection and flow along the channel of the microfluidic chip to the subsequent detection area.

[0040] The cross-shaped flow focusing structure has the following beneficial effects.

[0041] 1. Efficient generation: the cross-shaped flow focusing structure can ensure the rapid and continuous generation of microdroplets on the chip, improving the efficiency of sample processing.

[0042] 2. Stable and controllable: by adjusting the flow rate, flow ratio of the oil phase and sample fluid, and the geometric size of the channel, the size, shape and generation frequency of the microdroplets can be accurately controlled, realizing stable and controllable microdroplet generation.

[0043] 3. Reduce pollution: since the microdroplets are encapsulated by the oil phase, a relatively closed environment is formed, which helps to reduce pollution and interference of the sample during generation and transmission.

[0044] 4. Integrated design: Combined with subsequent absorbance, fluorescence and Raman detection zones, the cross-shaped flow focusing structure makes the entire microfluidic chip more compact and integrated, facilitating experimental operation and data acquisition.

[0045] 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 realizing online multi-parameter detection. This design reflects the unique advantages and broad application prospects of microfluidic chip technology in sample processing and detection.

[0046] It should 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.

[0047] Referring to Figure 2 In the T-shaped cross-flow structure, the first oil phase channel 111 is usually the main channel, and the sample channel 112 is the branch that intersects perpendicularly. When the oil phase flows from the branch into the main channel, it will produce a cross-flow effect with the sample flow at the intersection, thereby wrapping the sample in the oil phase to form microdroplets. This structure is simple to manufacture and suitable for generating microdroplets with relatively uniform size distribution.

[0048] The Y-shaped cross-flow structure is similar to the T-shaped structure, but the difference is that the branch intersects with the main channel in the form of a Y-shaped bifurcation. This structure can control the intersection of oil phase and 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 the uniformity of microdroplet size and shape.

[0049] In a preferred embodiment, referring to Figure 1 The second microdroplet generation zone 21 includes a second oil phase channel 211 and a Raman-enhanced particle channel 212. The second oil phase channel 211 is filled with a second oil phase, and the Raman-enhanced particle channel 212 is filled with Raman-enhanced particles. The second oil phase channel 211 and the Raman-enhanced particle channel 212 converge and communicate with the second absorbance detection zone 22.

[0050] The Raman-enhanced particle channel 212 is specifically used to transport Raman-enhanced particles. Raman-enhanced particles are substances that can significantly enhance Raman signals, usually with large specific surface area and special surface structure, capable of strong interaction 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 microdroplets when needed.

[0051] The second oil phase channel 211 is similar to the first oil phase channel 111, and a second oil phase flows through the second oil phase channel 211. This oil is also used to encapsulate the Raman-enhancing particles, forming oil-in-particle microdroplets. The selection of the oil phase should ensure that it is immiscible with the Raman-enhancing particles and can stably encapsulate the particles, preventing their aggregation or precipitation during subsequent processing.

[0052] The second oil phase channel 211 and the Raman-enhancing particle channel 212 intersect in a cross shape or other appropriate structure on the microfluidic chip. At the intersection, the oil phase encapsulates and cuts the Raman-enhancing particles into tiny droplets. These microdroplets then enter the second absorbance detection area 22 for preliminary optical property detection. By adjusting the size of the channels, flow rate, and flow ratio, the size, shape, and generation frequency of the microdroplets can be controlled.

[0053] In this way, the following advantages are achieved:

[0054] 1. Enhanced Raman signal: The introduction of Raman-enhancing particles can significantly improve the sensitivity of Raman detection, enabling the chip to detect lower concentrations of sample molecules.

[0055] 2. Parallel processing: The first and second microdroplet generation areas can work in parallel, simultaneously processing sample and Raman-enhancing particles, improving the overall processing efficiency of the chip.

[0056] 3. Multifunctional integration: Combined with subsequent fluorescence detection and Raman detection areas, the chip can achieve comprehensive analysis of multiple optical properties of the sample, providing more comprehensive and in-depth information for scientific research.

[0057] 4. Automation: The entire microdroplet generation and detection process can be automated through the microfluidic chip, reducing human factors and errors.

[0058] In summary, the design of the second microdroplet generation area 21 enables the microfluidic chip to efficiently generate microdroplets containing Raman-enhancing particles and perform subsequent fusion and detection with sample microdroplets. This design not only improves the sensitivity of Raman detection but also integrates multiple analysis techniques and automates the operation.

[0059] Further, the second oil phase channel 211 and the Raman-enhancing 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.

[0060] When selecting a specific intersection structure, the following factors need to be considered:

[0061] 1. Experimental requirements: Choose the appropriate structure according to the specific requirements of the experiment. For example, if uniform size distribution of microdroplets is required, a T-shaped or Y-shaped cross-flow structure may be more appropriate; if higher stability and controllability are required, a cross-shaped flow focusing structure may be more preferred.

[0062] 2. Chip fabrication difficulty: The fabrication difficulty of different structures may be different. When choosing, the laboratory's manufacturing ability and equipment conditions need to be considered comprehensively.

[0063] 3. Operation simplicity: The complexity of the structure may affect the simplicity of the operation. Choosing a simple and easy-to-operate structure can reduce the difficulty and cost of the experiment.

[0064] In summary, the intersection structure of the second oil phase channel 211 and the Raman enhancement particle channel 212 on the microfluidic chip has an important influence on the generation and subsequent detection of microdroplets. According to the experimental requirements and experimental conditions, choosing the appropriate structure is the key to ensuring the success of the experiment.

[0065] In a preferred embodiment, referring to Figure 1 The buffer zone 31 is a flat and curved disc structure.

[0066] The buffer zone 31 in the microfluidic chip mainly plays two key roles: one is to adjust the speed and stability of fluid flow, ensuring the smooth progress of subsequent processing steps; the second is to act as a reaction or mixing chamber, promoting the thorough mixing or reaction between different fluids.

[0067] The flat and curved disc 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 particles, molecules or reagents in the fluid to mix, react or diffuse.

[0068] The curved disc structure helps to reduce turbulence and vortex phenomena during fluid flow, improving the stability of fluid flow. This is particularly important for microfluidic experiments that require precise control of fluid behavior.

[0069] In the curved disc structure, the contact area between different fluids is increased, which is beneficial to their thorough mixing. For experiments that require mixing of multiple reagents or samples, this design can significantly improve the mixing efficiency.

[0070] Although the disc structure occupies a certain area in the plane, it can realize long-distance fluid flow in a limited space, thereby saving the vertical space on the chip. This is an important advantage for microfluidic chip designs with high integration requirements.

[0071] The planar curved disc structure can be easily integrated with other microfluidic elements such as microchannels, microvalves, micropumps, etc., to form a functional microfluidic system.

[0072] In practical applications, the planar curved disc structure buffer zone can be used in various microfluidic experiments, such as:

[0073] Sample pretreatment: Before the sample is sent to the detection area, the sample is diluted, filtered or enriched in the buffer zone for pretreatment operations.

[0074] Reagent mixing: In chemical reactions or biological experiments, multiple reagents are mixed in the buffer zone to ensure smooth reaction.

[0075] Product collection: After the reaction is completed, the product is introduced into the buffer zone for collection and storage for subsequent analysis or further processing.

[0076] In summary, the planar curved disc structure buffer zone 31 has important application value in microfluidic chip design, which can improve the stability and mixing efficiency of fluid flow, providing reliable protection for microfluidic experiments.

[0077] In a preferred embodiment, referring to Figure 1 It also includes an optical fiber 4, the light output end of which acts on the positions of the first absorbance detection area 12 and the second absorbance detection area 22, and the channels corresponding to the positions of the first absorbance detection area 12 and the second absorbance detection area 22 are droplet compression channels, which can improve the detection sensitivity by increasing the optical path.

[0078] The optical fiber 4 is mainly used for transmitting light in the microfluidic chip, and its light output end directly acts on the positions of the first absorbance detection area 12 and the second absorbance detection area 22. Such arrangement allows the light to directly irradiate the sample in the droplet compression channel, thereby performing absorbance detection.

[0079] The channels corresponding to the 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, which prolongs the interaction time between light and sample, thereby improving the accuracy of detection.

[0080] The droplet is squeezed in the compression channel, and the volume decreases, but the path of light through the droplet (i.e., the optical path) increases. This increases the opportunity for light to interact with sample molecules, thereby increasing the sensitivity of the detection. Due to the increase in optical path, the signal generated after the light is absorbed by the sample also increases accordingly. This allows even weak absorbance changes to be detected in low concentration samples. The design of the droplet compression channel also helps to reduce the interference of background light. By precisely controlling the illumination position and angle of the light, the light scattering and reflection in non-target areas can be minimized, thereby improving the signal-to-noise ratio of the detection signal.

[0081] This microfluidic chip design scheme combining optical fiber and droplet compression channel has wide 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 achieve rapid identification and quantitative analysis of pollutants in water, air and other samples.

[0082] By directly introducing light into the droplet compression channel of the microfluidic chip through the optical fiber, and using droplet compression to increase the optical path and improve the detection sensitivity, it is an innovative and effective microfluidic chip design scheme. This scheme not only improves the accuracy and sensitivity of detection, but also has wide application prospects and important practical value.

[0083] In a preferred embodiment, in the design of the microfluidic chip, in order to achieve the capture and residence of microdroplets in the first fluorescence detection zone 13, the second fluorescence detection zone 23 and the Raman detection zone 32, as shown in Figure 1 , using a cross-section expansion structure is an effective method. This design can ensure the stable residence of microdroplets in the detection zone, allowing sufficient time for optical detection and improving the accuracy and sensitivity of detection.

[0084] The cross-section expansion structure gradually increases the width or height of the channel before the detection zone, so that the flow rate of the fluid gradually slows down when passing through this area. When the microdroplet enters the cross-section expansion zone, due to the increase in the cross-section of the channel, its kinetic energy is dispersed, resulting in a significant reduction in the speed of the microdroplet, which eventually stays in the detection zone.

[0085] The capture and residence has the following advantages:

[0086] 1. Stable detection: The stable residence of microdroplets in the detection zone provides a stable environment for optical detection, reducing signal fluctuations caused by the movement of microdroplets and improving the accuracy of detection.

[0087] 2. Prolonged detection time: By capturing and staying, the residence time of microdroplets in the detection zone can be prolonged, allowing the detector to collect more signals and improving the sensitivity of detection.

[0088] 3. Easy integration: The cross-sectional expansion structure is relatively simple and easy to integrate with other microfluidic elements to form a functional microfluidic system.

[0089] In the first fluorescence detection zone 13 and the second fluorescence detection zone 23, the cross-sectional expansion structure can ensure the stable residence of the fluorescently labeled microdroplets in the detection zone, allowing the fluorescence detector to accurately capture the fluorescence signal for analyzing specific components or reaction products in the sample.

[0090] In the Raman detection zone 32, the cross-sectional expansion can also capture microdroplets containing Raman-enhanced particles, allowing them to stably reside at the detection point. The laser beam is focused on the microdroplet to excite Raman scattering, and by collecting and analyzing the Raman spectrum, the vibration and rotation information of the sample molecules can be obtained, and the chemical structure and composition of the sample can be inferred.

[0091] It should be noted that the proportion of cross-sectional expansion should be moderate, ensuring that the microdroplets can stably reside, and avoiding excessive expansion leading to fluid backflow or unnecessary vortex. The channel surface of the detection zone should be properly treated to reduce the interaction between the microdroplets and the channel wall, preventing the microdroplets from adhering or deforming. By precisely controlling the flow rate and flow of the fluid, it ensures that the microdroplets can smoothly enter and reside in the detection zone.

[0092] In summary, the cross-sectional expansion for capturing and residing microdroplets in the first fluorescence detection zone 12, the second fluorescence detection zone 22, and the Raman detection zone 32 is an effective microfluidic chip design strategy that can significantly improve the accuracy and sensitivity of optical detection.

[0093] In a preferred embodiment, to further improve the accuracy and efficiency of Raman detection, introducing a fusion microdroplet recognition element is an innovative and practical solution, i.e., a fusion microdroplet recognition element is arranged in the Raman detection zone 32, and Raman detection is performed in response to the recognition of the fusion microdroplet by the microdroplet recognition element. This design can ensure that Raman detection is only performed when a fusion microdroplet is identified, thereby avoiding unnecessary detection operations and improving the automation and intelligence level of the detection process.

[0094] The fusion microdroplet recognition element is a device that can detect and recognize fusion microdroplets in a microfluidic chip, arranged near the Raman detection zone, and can sense the fusion event of the microdroplets through optical, electrical, or mechanical methods. When two or more microdroplets containing different components fuse under certain conditions, the recognition element will send a signal to trigger the subsequent Raman detection process.

[0095] Microdroplet fusion: In a specific area of the microfluidic chip (such as fusion zone 31), by precisely controlling the flow rate, flow volume and channel structure of the fluid, microdroplets containing different components are fused. These microdroplets may contain samples, reaction reagents or Raman-enhanced particles, etc.

[0096] 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.

[0097] Triggering Raman detection: The recognition signal is transmitted to the control system, which determines whether Raman detection is needed according to the preset program. If it is confirmed that the fused microdroplet meets the detection conditions, the control system will start the Raman detector to perform Raman spectrum analysis on the fused microdroplet.

[0098] Data analysis: The spectrum 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.

[0099] The present application can ensure that the detection object is the expected fusion product by recognizing the fused microdroplet and performing Raman detection, avoiding the interference of non-target microdroplets. Since detection is only performed when the fused microdroplet is recognized, unnecessary detection operations are reduced, improving the automation and intelligence level of the detection process. The introduction of the fused microdroplet recognition element makes the microfluidic chip system more flexible, allowing for adjustment of detection strategies and processes according to experimental needs.

[0100] This microfluidic chip design scheme combining fused microdroplet recognition elements and Raman detection zones has wide application prospects in the fields of biochemistry, drug analysis, environmental monitoring, etc. It can not only be used to study molecular interactions and reaction mechanisms in complex biological samples, but also be used for rapid screening and identification of drug, pollutant, etc. target molecules. With the continuous progress of technology and the reduction of cost, this microfluidic chip system is expected to be more widely applied and popularized in the future.

[0101] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods, which are all included in the protection scope of the present application.

Claims

1. A microfluidic chip for realizing online detection of Raman, fluorescence and absorbance, characterized in that, It comprises a first microdroplet generating channel (1), a second microdroplet generating channel (2) and a microdroplet fusion channel (3); One of the first microdroplet generating channel (1) and the second microdroplet generating channel (2) is used for generating sample microdroplets, and the other is used for generating Raman enhanced particle microdroplets; The first microdroplet generating channel (1) and the second microdroplet generating channel (2) are symmetrically arranged, and the channel outlets of the two are connected and communicated with the channel inlet of the microdroplet fusion channel (3); The first microdroplet generating channel (1) comprises a first microdroplet generating area (11), a first absorbance detection area (12) and a first fluorescence detection area (13) arranged in sequence along the medium flow direction; the second microdroplet generating channel (2) comprises a second microdroplet generating area (21), a second absorbance detection area (22) and a second fluorescence detection area (23) arranged in sequence along the medium flow direction; the microdroplet fusion channel (3) comprises a buffer area (31) and a Raman detection area (32) arranged in sequence along the microdroplet flow direction, the buffer area (31) is a flat and curved disc structure, and the Raman detection area (32) is arranged with a fusion microdroplet recognition element, and the Raman detection is performed in response to the recognition of the fusion microdroplet by the microdroplet recognition element; The first fluorescence detection area (13), the second fluorescence detection area (23) and the Raman detection area (32) achieve microdroplet capture and residence through cross-section expansion.

2. The microfluidic chip for realizing online detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The first microdroplet generating area (11) comprises a first oil phase channel (111) and a sample channel (112), the first oil phase channel (111) is passed through with a first oil phase, and the sample channel (112) is passed through with a sample to be detected, and the first oil phase channel (111) and the sample channel (112) are communicated with 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 T-shaped cross-flow structure, Y-shaped cross-flow structure or cross-shaped flow focusing structure on the microfluidic chip.

4. The microfluidic chip for realizing on-line detection of Raman, fluorescence and absorbance according to claim 1, characterized in that: The second microdroplet generating area (21) comprises a second oil phase channel (211) and a Raman enhanced particle channel (212), the second oil phase channel (211) is passed through with a second oil phase, and the Raman enhanced particle channel (212) is passed through with Raman enhanced particles, and the second oil phase channel (211) and the Raman enhanced particle channel (212) are communicated with the second absorbance detection area (22) after converging.

5. The microfluidic chip of claim 4, wherein the microfluidic chip is capable of performing Raman, fluorescence, and absorbance online detection. The second oil phase channel (211) and the Raman enhanced particle channel (212) are in T-shaped cross-flow structure, Y-shaped cross-flow structure or cross-shaped flow focusing structure on the microfluidic chip.

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

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