Preparation method of micro-fluidic chip of multifunctional sensing system

Abstract

The invention relates to the field of microfluidic technology and sensors, and discloses a preparation method of a microfluidic chip of a multifunctional sensing system, which comprises the following steps: setting specific parameters by using an ultraviolet laser marking machine, carrying out laser cutting to obtain a circular PET film, pasting 3M glue, and carrying out laser cutting to prepare a microfluidic chip pressure release valve layer. The method comprises the following steps: pasting a baffle formed by cutting a PI film at a valve, then carrying out plasma cleaning, removing the baffle after cleaning, pasting a 3M adhesive tape, then cutting a channel main body, scanning the prepared PI film according to set laser parameters to obtain laser-induced graphene with a high carbonization degree, and finally, carrying out ultraviolet laser cutting through C4D software of an ultraviolet laser cutting machine. The method comprises the following steps of: performing personalized design and cutting on a laser-induced pattern, selecting a proper pattern as a detection electrode of the micro-fluidic chip, performing PET (Polyethylene Terephthalate) packaging on a leakage channel layer of the micro-fluidic chip and the detection electrode prepared from the laser-induced graphene, and comprehensively packaging each layer of the micro-fluidic chip to prepare the micro-fluidic chip.

Description

Technical Field

[0001] The present invention relates to the technical fields of microfluidics and sensor technology, and specifically to a preparation method of a microfluidic chip for a multifunctional sensing system. Background Art

[0002] In recent years, the rapid development of microfluidics technology has attracted wide attention and become an important research direction in the fields of biomedicine, chemical analysis, environmental monitoring, etc. Microfluidic chips, with their advantages of high efficiency, low consumption, and rapid reaction, have gradually replaced traditional laboratory analysis methods, especially showing great potential in sample analysis and detection. The core of a microfluidic chip lies in its fluid manipulation ability, which realizes the mixing, reaction, and separation of samples by precisely controlling the flow of tiny liquids. In order to improve the functionality of microfluidic chips, the application of various materials and structures becomes particularly important. Among them, high-performance polymers such as polyethylene terephthalate (PET) and polyimide (PI) are widely used in the preparation of microfluidic chips due to their good physical and chemical stability.

[0003] Laser cutting technology has become an important means in the manufacture of microfluidic chips due to its high precision and flexibility. Through an ultraviolet laser marking machine, channels and valve structures with the required shapes can be precisely cut on a PET film. This method not only improves the preparation efficiency but also enables complex microfluidic designs to meet the needs of different applications. In the application of microfluidic chips, the integration of sensors is a key technical point. Using laser-induced graphene (LIG) as a detection electrode, its excellent conductivity and sensitivity make the microfluidic chip have broad application prospects in the fields of environmental monitoring and biosensing. The isotropic characteristics of graphene materials make them perform excellently in strain sensing, which can effectively quantify external strain and improve the performance of sensors.

[0004] However, there are still some problems in the preparation and functional integration of microfluidic chips in the prior art. For example, traditional preparation processes are often complex and time-consuming, and the selection of materials and structural design are also restricted. In addition, existing sensors often cannot work stably under various environmental conditions, affecting their actual application effects. Therefore, developing a new preparation method for a microfluidic chip of a multifunctional sensing system, which can effectively solve the above problems and achieve efficient and stable sensing capabilities, has important application value. The present invention aims to overcome the above technical bottlenecks and prepare a high-performance microfluidic chip through innovative laser cutting and material integration methods, providing a new solution for the progress of sensor technology. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a preparation method for a microfluidic chip of a multifunctional sensing system, aiming to overcome the deficiencies of existing microfluidic chips in functionality and preparation efficiency through innovative laser cutting and material integration technologies, thereby improving their performance and applicability in various application scenarios.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: A preparation method for a microfluidic chip of a multifunctional sensing system, comprising the following steps:

[0007] S1. Material preparation and laser cutting: The present invention first uses an ultraviolet laser marking machine to perform laser cutting on a circular polyethylene terephthalate (PET) film under specific parameter settings. Through precise laser control, high-precision cutting of the PET film can be achieved to obtain the required shape and size. This process not only improves the cutting efficiency but also ensures the smoothness of the cutting edge, reducing problems in subsequent processes.

[0008] S2. Pasting and valve layer preparation: After completing the cutting of the PET film, 3M tape is pasted to enhance the structural stability. Subsequently, laser cutting technology is used to prepare the pressure relief valve layer of the microfluidic chip. The design of this layer is crucial for the stable operation of the microfluidic system and can effectively control the flow of fluid inside the chip to avoid leakage.

[0009] S3. Production and cleaning of the baffle: A polyimide (PI) film baffle cut into shape is pasted at the valve. After careful design, the function of the baffle is to control the flow direction and rate of the fluid. Subsequently, plasma cleaning is performed to remove surface contaminants, ensuring good adhesion and the cleanliness of the fluid channels. This process improves the reliability of subsequent processes and ensures good bonding between layers.

[0010] S4. Preparation of the microfluidic drainage channel layer: After cleaning, the baffle is removed and pasted with 3M tape. Subsequently, the channel body is cut to form the microfluidic drainage channel layer. The design and size of the channel have a direct impact on the flow characteristics of the fluid. Therefore, the precision of laser cutting is particularly important in this link.

[0011] S5. Preparation of laser-induced graphene: By setting specific laser parameters, the PI film is scanned to prepare laser-induced graphene with a high degree of carbonization. This material exhibits good isotropic characteristics when facing lateral and longitudinal bending, greatly enhancing its quantification ability in strain sensing. The preparation process of laser-induced graphene not only simplifies traditional chemical synthesis methods but also enables highly customized pattern design.

[0012] S6. Personalized Design and Encapsulation: Finally, using the C4D software built into the ultraviolet laser cutting machine, the laser-induced pattern is personalized designed, and a suitable detection electrode is cut out. Through PET encapsulation of the drainage channel layer of the microfluidic chip and the detection electrode prepared by laser-induced graphene, comprehensive encapsulation of the multi-layer structure is achieved. This design ensures the stability and reliability of the microfluidic chip in practical applications, while improving its detection performance.

[0013] The present invention provides a preparation method for a microfluidic chip of a multifunctional sensing system. It has the following beneficial effects:

[0014] 1. Through the high-precision cutting technology of the ultraviolet laser marking machine, the present invention optimizes the preparation process of the microfluidic chip. The circular PET film and the pressure relief valve layer are cut using specific laser parameters (such as pulse frequency 100 - 140 kHz, scanning speed 20 - 40 mm / s), significantly simplifying the complex steps of the traditional process, increasing the production efficiency by more than 20%, and at the same time ensuring a smooth cutting edge and avoiding the risk of fluid leakage.

[0015] 2. Through the in-situ preparation technology of laser-induced graphene (LIG), the present invention realizes the integration of high-sensitivity sensors. The PI film is laser-induced with set parameters (pulse frequency 110 - 130 kHz, pulse width 1 - 3 μs) to generate graphene with a high degree of carbonization (>90%). Its excellent conductivity (electrical conductivity can reach 10 3 S / m) and isotropic characteristics enable the chip to still stably quantify external strain when bent horizontally and vertically, and the sensor response speed is increased by 30%.

[0016] 3. Through plasma cleaning and precise control of the multi-layer microstructure, the present invention improves the stability and reliability of the chip. A PI film baffle is set in the pressure relief valve layer and pollutants are removed through plasma cleaning. Combining with the layered bonding technology of 3M tape, it ensures that the main channel (width 300 - 500 μm) is tightly bonded to the electrode layer, and the working life of the chip in high-temperature and high-humidity environments is extended to 2 times that of the traditional design.

[0017] 4. Through personalized electrode design and support of the C4D software, the present invention enhances the customization and adaptation ability of the chip. The LIG electrode pattern (such as interdigital electrode, spiral electrode) is freely designed using the C4D software supporting the ultraviolet laser cutting machine, and sensors can be quickly customized for different detection targets such as pH, glucose, heavy metal ions, etc., and the detection sensitivity covers the concentration range of 0.01 - 100 μM.

[0018] 5. Through the optimization of PET flexible packaging and multi-layer structure, the present invention achieves high compatibility and portability. After the layer-by-layer alignment of the microfluidic drainage channel layer and the LIG electrode layer, PET film is used for full encapsulation, controlling the chip thickness within 0.2 - 0.5 mm and the bending radius to be below 3 mm. It has both the compatibility with medical wearable devices and the scalability for industrial production, reducing the comprehensive cost by 40%. Description of the Drawings

[0019] Figure 1 Schematic SEM photograph of laser-induced graphene of the microfluidic chip electrode prepared in Example 1 of the present invention;

[0020] Figure 2 Magnified schematic SEM photograph of laser-induced graphene of the microfluidic chip electrode prepared in Example 1 of the present invention;

[0021] Figure 3 Schematic optical microscope photograph of laser-induced graphene of the microfluidic chip electrode prepared in Example 1 of the present invention;

[0022] Figure 4 Schematic diagram of the performance curve of the pH detection electrode of laser-induced graphene of the microfluidic chip electrode prepared in Example 1 of the present invention;

[0023] Figure 5 Schematic diagram of the performance curve of the glucose detection electrode of laser-induced graphene of the microfluidic chip electrode prepared in Example 1 of the present invention;

[0024] Figure 6 Schematic diagram of the performance curve of the heavy metal detection electrode of laser-induced graphene of the microfluidic chip electrode prepared in Example 2 of the present invention;

[0025] Figure 7 Schematic SEM photograph of the longitudinally scanned laser-induced graphene material of the microfluidic chip electrode prepared in Example 2 of the present invention;

[0026] Figure 8 Schematic SEM photograph of the laterally scanned laser-induced graphene material of the microfluidic chip electrode prepared in Example 3 of the present invention;

[0027] Figure 9 Flow chart of the preparation method of the present invention;

[0028] Figure 10 Schematic diagram of the microfluidic chip structure of the multi-functional sensing system in the present invention. Detailed Description of the Invention

[0029] Next, in combination with the accompanying drawings of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment 1:

[0031] Please refer to the attached Figure 1 - attached Figure 10 , the embodiment of the present invention provides a method for preparing a microfluidic chip based on standard laser cutting, including the following steps:

[0032] S1. Material preparation:

[0033] Select a PET film with a thickness of 100 μm as the base material to ensure its good transparency and mechanical strength.

[0034] Use a polyimide (PI) film with a thickness of 50 μm for subsequent baffle production.

[0035] S2. Laser cutting:

[0036] Use an ultraviolet laser marking machine, set the laser parameters as the pulse frequency of 150 kHz, the pulse width of 2 μs, and the scanning speed of 30 mm / s, and perform circular cutting on the PET film with a cutting diameter of 10 mm to obtain the required circular structure.

[0037] S3. Valve layer preparation:

[0038] Paste 3M tape on the cut PET film to increase the stability of the structure.

[0039] Through laser cutting technology, fabricate the pressure relief valve layer of the microfluidic chip, and set the size of the valve to 3 mm x 3 mm.

[0040] S4. Baffle production and cleaning:

[0041] Cut the PI film into a baffle matching the valve with a thickness of 50 μm and paste it on the valve.

[0042] Perform plasma cleaning to remove surface dirt and impurities, and the cleaning time is 5 minutes.

[0043] S5. Preparation of the relief channel layer:

[0044] After removing the baffle, paste 3M tape and use laser cutting to cut the main body of the channel to ensure that the channel width is 500 μm.

[0045] S6. Preparation of laser-induced graphene:

[0046] Place the cleaned PI film under an ultraviolet laser, and set the laser parameters as follows: pulse frequency is 120 kHz, pulse width is 1.5 μs, and scanning speed is 25 mm / s to prepare laser-induced graphene.

[0047] S7. Detection electrode design and encapsulation:

[0048] Perform personalized design through C4D software, cut out suitable detection electrodes, and finally perform PET encapsulation on each layer of the microfluidic chip.

[0049] Advantages of Example 1: The SEM photos of the laser-induced graphene material prepared in Example 1 are as shown in Figure 1 and 2 shown. As can be seen from Figure 1 , the laser-induced graphene material exhibits regular structural characteristics, with a uniform surface and good stability, meeting the expected performance requirements. This structure helps to improve the sensitivity and response speed of the sensor. Figure 2 is an enlarged view. The surface of the material shows delicate textures, indicating that the laser treatment process effectively promotes the formation of graphene, which helps to enhance the electrical conductivity and chemical stability of the electrode. In addition, this uniform surface structure is crucial for the sensing performance of the microfluidic chip and can provide a better electrochemical reaction interface;

[0050] At the same time, the cyclic voltammetry characteristic curve of the laser-induced graphene (LIG) working electrode prepared in Example 1 is as shown in Figure 4 shown. The experimental results show that after activation treatment, the cyclic voltammetry test of the electrode in 0.1 M PBS solution is carried out with a voltage scanning range of -0.2 to 1.6 V and a scanning rate of 0.1 V·s -1 . After 10 cycles of cyclic scanning, the finally obtained voltammetry characteristic curve tends to be stable. This indicates that the activation process of the electrode is completed and its electrochemical performance has reached the expected effect;

[0051] Finally, by comparing the curve changes under different scanning cycles, it can be seen that as the number of cycles increases, the electrochemical activity of the electrode gradually increases, indicating that the surface state of LIG has been effectively improved. In addition, the excellent electrical conductivity and large specific surface area of LIG provide a good substrate for the sensor, which helps to improve its detection sensitivity and response speed.

[0052] Example 2: A preparation method of a microfluidic chip with optimized laser parameters, including the following steps:

[0053] S1. Material preparation:

[0054] Select a PET film with a thickness of 75 μm and a PI film with a thickness of 40 μm.

[0055] S2. Laser cutting:

[0056] Set the laser parameters as pulse frequency of 100 kHz, pulse width of 1 μs, and scanning speed of 20 mm / s, and cut the PET film to obtain a circular structure with a diameter of 8 mm.

[0057] S3. Preparation of the valve layer:

[0058] Paste 3M tape on the cut PET film, and then laser cut to make the valve layer with a valve size of 2 mm x 2 mm.

[0059] S4. Production and cleaning of the baffle:

[0060] Use PI film to make the baffle and perform plasma cleaning for 5 minutes to ensure no pollution.

[0061] S5. Preparation of the discharge channel layer:

[0062] After removing the baffle, paste it with 3M tape, and then cut the channel body with a channel width set to 300 μm.

[0063] S6. Preparation of laser-induced graphene:

[0064] Set the laser parameters as pulse frequency of 130 kHz, pulse width of 2.5 μs, and scanning speed of 22 mm / s, and perform laser induction on the PI film.

[0065] S7. Design and encapsulation of the detection electrode:

[0066] Use C4D software to design the electrode, complete the cutting, and finally perform PET encapsulation on each layer.

[0067] Advantages of Example 2: The SEM photo of the laser-induced graphene material prepared in Example 2 is as Figure 7 shown. It can be seen from the figure that the stripe structure formed after increasing the printing spacing to 0.05 mm is obvious. Compared with the grid structure in Example 1, the scanning method of sweeping once adopted in this example results in fewer conductive paths and lower carbonization degree. This indicates that at a larger printing spacing, the microstructure of the material has changed, which may affect its conductivity;

[0068] And by comparing the LIG materials with two different scanning methods, it can be seen that the change in printing spacing has a significant impact on the conductivity and structural uniformity of the material.

[0069] Example 3: A method for preparing a microfluidic chip based on different material combinations, including the following steps:

[0070] S1. Material preparation:

[0071] Select a PET film with a thickness of 50 μm and a PI film with a thickness of 30 μm.

[0072] S2. Laser cutting:

[0073] Using laser parameters with a pulse frequency of 140 kHz, a pulse width of 1.8 μs, and a scanning speed of 35 mm / s, cut out a circular structure with a diameter of 12 mm.

[0074] S3. Preparation of the valve layer:

[0075] Paste 3M tape on the PET film, and then use laser cutting to make the valve layer. The valve size is 4 mm x 4 mm.

[0076] S4. Baffle production and cleaning:

[0077] When making the baffle, use the PI film for cutting and perform plasma cleaning for 6 minutes.

[0078] S5. Preparation of the discharge channel layer:

[0079] After removing the baffle, paste 3M tape and cut the channel body. The channel width is set to 400 μm.

[0080] S6. Preparation of laser-induced graphene:

[0081] Set the laser parameters with a pulse frequency of 110 kHz, a pulse width of 2 μs, and a scanning speed of 28 mm / s, and perform laser induction on the PI film.

[0082] S7. Detection electrode design and encapsulation:

[0083] Design the electrode pattern through C4D software, cover Bi on the upper layer of the LIG prepared in the previous step and then complete the cutting. Finally, comprehensively encapsulate each layer of the microfluidic chip.

[0084] Beneficial effects of Example 3: The SEM photo of the laser-induced graphene material prepared in this Example 3 is as Figure 8 shown. It can be seen from the SEM image that the surface of the laser-induced graphene material presents an obvious stripe structure, indicating that the material has good uniformity and consistency. Compared with Example 1, after replacing the intermediate layer material with Bi in this example, a reduction in the conductive path and a decrease in the degree of carbonization are observed.

[0085] Comparative experiment:

[0086] I. Experimental purpose

[0087] Compare the effects of different process parameters (laser parameters, material combinations) on the performance of microfluidic chips, verify the advantages and disadvantages of the three embodiments of the present invention in terms of core indicators such as conductivity, detection sensitivity, and structural stability, and clarify the applicable scenarios of each solution.

[0088] II. Experimental Design and Parameter Comparison

[0089]

[0090] III. Test Items and Methods

[0091] Conductivity Test

[0092] Method: Four-probe method (Instrument: RTS-9 Dual-Electrical-Measurement Digital Four-Probe Instrument)

[0093] Indicators: Conductivity (S / m), resistance change rate (ΔR / R0) under lateral and longitudinal bending (bending radii of 5 mm and 3 mm).

[0094] Detection Sensitivity Test

[0095] Targets: pH (H + , 0.01 - 1.0 M), glucose (1 - 100 μM), Pb 2+ (0.01 - 10 μM).

[0096] Method: Cyclic voltammetry (CHI760E Electrochemical Workstation), record the linear range and detection limit (LOD, S / N = 3).

[0097] Structural Characterization

[0098] SEM and EDX analysis (Instrument: Hitachi SU8010): Observe the carbonization uniformity and Bi layer coverage.

[0099] Raman spectroscopy (532 nm laser): Intensity ratio of graphene characteristic peaks (I D / I G ).

[0100] Mechanical Stability Test

[0101] Bending cycle test (500 times, bending radius of 3 mm);

[0102] Detect performance attenuation after environmental aging (85°C / 85% RH, 240 hours).

[0103] Manufacturing Efficiency and Cost

[0104] Processing duration (single-layer cutting time);

[0105] Material loss rate (scrap ratio).

[0106] IV. Experimental Results and Comparative Analysis

[0107] 1. Comparison of Electrical Conductivity

[0108] Index Example 1 Example 2 Example 3 Conductivity (S / m) <![CDATA[1.23×10 3 > <![CDATA[8.65×10 2 > <![CDATA[9.01×10 2 > <![CDATA[Transverse bending ΔR / R0(%)]]> 4.7 (5 mm radius) 7.2 (3 mm radius) 5.6 (5 mm radius) <![CDATA[Longitudinal bending ΔR / R0(%)]]> 3.8 (5 mm radius) 9.1 (3 mm radius) 10.5 (5 mm radius)

[0109] Analysis:

[0110] The high-frequency narrow pulse-width laser (120 kHz / 1.5 μs) in Example 1 generates denser graphene with the best conductivity;

[0111] Increasing the printing spacing in Example 2 results in fewer conductive paths and a decrease in conductivity (a 29.7% decrease);

[0112] Covering the Bi layer in Example 3 introduces interface resistance, and the overall conductivity is slightly lower than that in Example 1.

[0113] 2. Comparison of Detection Sensitivity

[0114]

[0115] Analysis:

[0116] Example 1 is suitable for broad-spectrum pH and glucose detection;

[0117] After optimization in Example 2, the signal-to-noise ratio for glucose detection is improved (LOD is reduced by 50%);

[0118] Example 3 significantly improves the selectivity for heavy metals (Pb 2+ ) through the Bi composite layer (specific chelation between Bi and Pb).

[0119] 3. Results of Structural Characterization

[0120] SEM( Figure 1 / 7 / 8):

[0121] Example 1: Honeycomb-like porous structure (pore size 1 - 2 μm), with neat edges;

[0122] Example 2: Longitudinal stripes (spacing 0.05 mm), with an increase in under-carbonized areas;

[0123] Example 3: After covering the Bi layer, the surface has obvious granularity, and the holes in some areas are blocked.

[0124] Raman analysis:

[0125] I D / I G Ratio: Example 1 (0.92) < Example 2 (1.15) < Example 3 (1.32), indicating that Example 1 has the fewest defects.

[0126] 4. Mechanical Stability and Environmental Tolerance

[0127]

[0128]

[0129] Analysis:

[0130] Example 1 adopts standard parameters and a complete encapsulation structure, with the best long-term stability;

[0131] The Bi layer of Example 3 is slightly passivated in a humid environment but still maintains high sensitivity.

[0132] 5. Comparison of manufacturing efficiency and economy

[0133] Index Example 1 Example 2 Example 3 Single-layer cutting time 25s 30 s (spacing adjustment) 35 s (Bi deposition) Material loss rate (%) 3.2 5.8 7.1 (Bi sputtering)

[0134] V. Comparison conclusions and solution recommendations

[0135] Example 1 (standard parameters):

[0136] Advantages: High conductivity, broad-spectrum detection applicability (pH / glucose), lowest cost;

[0137] Applicable scenarios: Routine medical tests, environmental monitoring.

[0138] Example 2 (optimized laser parameters):

[0139] Advantages: Improved glucose detection sensitivity (LOD 0.05 μM), narrow channel (300 μm) suitable for trace samples;

[0140] Limitations: Poor mechanical stability, not suitable for frequently bent scenarios.

[0141] Example 3 (Bi composite electrode):

[0142] Advantages: Pb 2 + detection LOD reaches 0.01 μM (10 times higher than the national standard), suitable for industrial wastewater detection;

[0143] Limitations: High cost, only recommended for special heavy metal detection.

[0144] VI. Comprehensive analysis of technical economy

[0145] Select the optimal solution according to different requirements:

[0146] Large-scale production: Give priority to Example 1 (balancing performance and cost);

[0147] High-sensitivity detection: Select Example 2 or 3 according to the target substance type;

[0148] Harsh environment monitoring (high humidity / bending): Example 1 + customized encapsulation layer optimization.

[0149] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a microfluidic chip of a multifunctional sensing system, characterized in that: The following steps are involved: S1. Cutting of circular PET film: Cutting circular PET film of required size according to set parameters by UV laser marking machine; S2. Preparation of the pressure relief valve layer: The cut circular PET film is pasted with 3M glue, and then laser cutting is performed thereon to prepare the pressure relief valve layer of the microfluidic chip; S3. Pasting and cleaning of baffles: Paste baffles cut from PI film on the valve, perform plasma cleaning, and remove the baffles after cleaning; S4. Cutting of the channel body: After pasting the 3M tape, cut the channel body to obtain the microfluidic leakage channel layer; S5. Preparation of laser-induced graphene: Scanning the PI film with set laser parameters to obtain laser-induced graphene with a high degree of carbonization, so that the material is isotropic when facing lateral and longitudinal bending; S6. Design and cutting of detection electrodes: Use the C4D software provided by the UV laser cutting machine to design and cut the laser-induced pattern in a personalized way, and select the appropriate pattern as the detection electrode of the microfluidic chip; S7. Chip packaging: The leakage channel layer of the microfluidic chip and the detection electrode prepared by laser-induced graphene are PET packaged, and finally all layers of the microfluidic chip are fully packaged to complete the preparation of the microfluidic chip.

2. The method for preparing a microfluidic chip of a multifunctional sensing system according to claim 1, characterized in that: The circular PET film cut in step S1 has a thickness of 50-100 μm.

3. The method for preparing a microfluidic chip of a multifunctional sensing system according to claim 1, characterized in that: The parameters of the laser cutting in step S2 are set as follows: the pulse wave frequency is 100-140kHz, the pulse width is 1-3μs, and the scanning speed is 20-40mm / s.

4. The method for preparing a microfluidic chip of a multifunctional sensing system according to claim 1, characterized in that: The laser cutting parameters for cutting the channel body in step S4 are: pulse wave frequency of 15-25 kHz, pulse width of 0.3-0.7 μs, and scanning speed of 10-30 mm / s.

5. The method for preparing a microfluidic chip of a multifunctional sensing system according to claim 1, characterized in that: The thickness of the PI film in step S5 is 40-100 μm.

6. The method for preparing a microfluidic chip of a multifunctional sensing system according to claim 1, characterized in that: The packaging material in step S7 is a PET film.

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