Microfluidic device for human body sweat collection and ion detection and manufacturing method thereof

Abstract

The invention provides a microfluidic device for human sweat collection and ion detection and a manufacturing method, and belongs to the technical field of microfluidic devices.The device is sequentially provided with a sweat discharge block, a supporting layer, a sealing layer, a microfluidic layer, a detection layer, an inlet layer and a skin adhesion layer from top to bottom, the supporting layer, the sealing layer, the micro-fluidic layer, the detection layer, the inlet layer and the skin adhesion layer are sequentially attached and connected, all the layers are adhered and bonded through adhesive layers to form a laminated structure, a square window is formed in the supporting layer, the sweat discharging block is embedded into the square window, the lower surface of the sweat discharging block is attached to the upper surface of the sealing layer, and the sweat discharging block is connected with the skin adhesion layer. A longitudinal outlet capillary tube is arranged between the sealing layer and the microfluidic layer, and a longitudinal inlet capillary tube is arranged between the detection layer and the inlet layer. The micro-fluidic device provided by the invention solves the problems of poor sealing performance and low collection efficiency of the existing device, ensures low-cost and high-efficiency micro-fluidic device production, and realizes batch production.

Description

Technical Field

[0001] The present invention relates to the technical field of microfluidic devices, and in particular to a microfluidic device for human sweat collection and ion detection and a manufacturing method thereof. Background Art

[0002] Using human epidermal fluids to detect physiological markers and reflect physical health is a new type of human bioinformation and physiological indicator analysis technology that has emerged in recent years. At present, most health indicator tests in hospitals use blood samples. Blood analysis is considered the gold standard for health status assessment. However, in practical applications, blood analysis can cause irritation and trauma to the human body, and it is very difficult to take samples multiple times in a short period of time, which greatly reduces the frequency of sample collection and testing. For patients with chronic diseases such as diabetes, hyperuricemia, and kidney disease, it is crucial to realize human physiological indicators (especially ion concentration detection in body fluids). Flexible wearable detection devices are attached to the human body to collect biological samples and perform tests in real time and continuously, which has the advantages of non-invasiveness, non-irritation, and long-term continuous collection. In many application scenarios, it can replace blood collection-based detection.

[0003] However, in existing research, common body fluid research objects include saliva, tears, sweat, etc. Among them, saliva is easily contaminated by food in the mouth, and the collection and detection of tears are too irritating to the eyes and can easily cause discomfort to the human body. In contrast, sweat is a body fluid research object that is easy to sample. At the same time, studies have shown that there is a good correlation between the concentrations of biomarkers in sweat and blood, providing a richer source of human physiological indication signals for disease diagnosis and continuous follow-up, among which electrolytes, such as Na + , K + , Ca 2+ and Cl - etc. are feedback indicators of various human diseases. Therefore, wearable flexible sensor detection devices based on sweat detection of human epidermis can build a fusion of human physical, chemical and biological indicator signals, and promote rapid detection and continuous monitoring of human physiological markers.

[0004] Wearable flexible sweat detection equipment collects sweat and analyzes the electrolyte ion concentration in it. During the detection process, reliable automatic sweat collection is the basis for accurately measuring biomarkers in sweat. This technology plays a vital role in improving the efficiency and accuracy of detection. Incorrect collection methods or procedures will cause a large amount of sweat sample loss, serious sweat contamination during sweat transportation and processing, and ultimately cause huge errors in the detection process. The development of flexible wearable sweat detection equipment requires the support of advanced sweat collection and manipulation technology. On this basis, the use of electrochemical methods to identify and detect ions can achieve high-integration detection in a limited space, which is the future development direction.

[0005] At present, researchers have developed a chemical stimulation method that uses chemical agonists such as pilocarpine in combination with electrophoresis technology to induce sweating on the human epidermis. Although this method can induce sweating, a suitable sweat collection device is still required to ensure the integrity of the sample. Microfluidic chips can efficiently collect and analyze sweat. In the design of flexible microfluidic devices for sweat collection, the device uses a lower base plate and an upper cover plate to bond the overall structure together to form a closed microfluidic cavity structure, including microchannels, micro-liquid storage chambers and other structures, so that it has physical and chemical analysis functions such as sampling, flow, and separation. Existing research provides a paper-based microfluidic patch with a three-dimensional folding structure. The three-dimensional microfluidic channel using fiber pores can absorb sweat and control fluid flow. The collection, flow and evaporation of sweat are achieved. However, the paper chip has poor control accuracy for sweat. After repeated use, it will cause mixing of new and old sweat before and during detection. In addition, existing research also provides a wearable electrochemical sensor based on surface tension gradient driven electrolyte flow to detect Cu2 + The surface tension gradient drives the electrolyte to flow toward the pre-concentrated ions, accelerating the transfer of ions and electrons and generating a larger electrochemical signal. By using a flexible polymer material as the substrate and designing the size, shape and surface hydrophilicity of the microchannel, the sweat control ability can be significantly improved.

[0006] In the preparation process of flexible microfluidic devices for sweat collection, flexible materials are used as the substrate, and the microstructures on the lower base and upper cover are required not to be contaminated or deformed. Some scholars have designed a microfluidic system based on polydimethylsiloxane (PDMS) to spontaneously collect sweat to the detection area. The sweat collection rate is improved by depositing polyvinyl alcohol to form a hydrophilic surface. However, the fluid chambers connected by microchannels are easily affected by blockages such as sebum, resulting in poor ion exchange and destroying the detection stability. Existing research has made certain progress in the design, structural integration and materials of microfluidic devices for electrochemical detection of sweat. However, the structural design and flow rate control of the fluid chamber of microfluidic devices with high integration and high controllability still need further exploration. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a microfluidic device and a manufacturing method for human sweat collection and ion detection, which solves the problems of poor sealing and low collection efficiency of existing devices, while ensuring low-cost and high-efficiency production of microfluidic devices and realizing mass production.

[0008] To achieve the above object, the present invention provides the following solutions: A microfluidic device for human sweat collection and ion detection comprises a sweat discharge block, a support layer, a sealing layer, a microfluidic layer, a detection layer, an inlet layer and a skin adhesion layer which are arranged in sequence from top to bottom, wherein the support layer, the sealing layer, the microfluidic layer, the detection layer, the inlet layer and the skin adhesion layer are sequentially bonded and connected, and each layer is bonded and bonded by an adhesive layer to form a stacked structure, a square window is provided on the support layer, the sweat discharge block is embedded in the square window and its lower surface is bonded to the upper surface of the sealing layer, a longitudinal outlet capillary is provided between the sealing layer and the microfluidic layer, and a longitudinal inlet capillary is provided between the detection layer and the inlet layer.

[0009] Preferably, a fluid inlet, an inlet flow channel, a detection chamber, an outlet flow channel, a fluid valve and a fluid outlet are arranged above the microfluidic layer. The detection chamber is a streamlined structure, which is connected to the inlet flow channel and the outlet flow channel respectively. The fluid inlet is connected to the inlet flow channel, and the outlet flow channel is connected to the fluid outlet through a fluid valve.

[0010] Preferably, the width of the inlet flow channel is 10~500μm and the length is 4mm, the width of the outlet flow channel is 200~800μm and the length is 100~3000μm, the length of the detection cavity is 3~15mm, the widest dimension is 2~6mm, and the diffusion angle at the connection between the detection cavity and the end of the inlet flow channel is 10°~75°.

[0011] Preferably, a first circular hole is opened on the sealing layer, and the longitudinal outlet capillary is embedded in a cylindrical cavity formed between the first circular hole and the fluid outlet, the upper surface of the longitudinal outlet capillary is in contact with the lower surface of the sweat discharge block, and the bottom end of the longitudinal outlet capillary is arranged inside the fluid outlet.

[0012] Preferably, a reference electrode and a working electrode are arranged on the detection layer, the working electrode is connected to the first detection interface via a first connecting wire, and the reference electrode is connected to the second detection interface via a second connecting wire, and the first detection interface and the second detection interface are arranged in parallel.

[0013] Preferably, a second circular hole is also opened at one end of the detection layer, a third circular hole corresponding to the second circular hole is arranged at the entrance layer, the longitudinal inlet capillary is embedded in the cylindrical cavity formed by the second circular hole, the third circular hole and the fluid inlet, the top end of the longitudinal inlet capillary passes through the second circular hole and is located in the fluid inlet of the microfluidic layer, the bottom of the longitudinal inlet capillary is arranged inside the corresponding sweat drainage port below, and the sweat drainage port is arranged on the surface of the skin adhesion layer.

[0014] Preferably, the surfaces of the skin adhesion layer, the inlet layer, the detection layer, the microfluidic layer, the sealing layer and the support layer are each provided with four groups of mutually symmetrical positioning pin holes, and the positioning pin holes provided in each layer are all connected.

[0015] Preferably, the sweat discharge block is made of paper or sponge, the support layer, sealing layer, microfluidic layer, detection layer and inlet layer are all made of flexible materials with a thickness of 10-1000 μm, and the skin adhesion layer is made of flexible materials with a thickness of 0.1-10 mm.

[0016] The present invention also provides a method for manufacturing the above-mentioned microfluidic device, comprising the following steps: S1. Cut the flexible material matrix by a cutting machine according to the pre-designed shape and size to obtain the basic shapes of the support layer, sealing layer, microfluidic layer, detection layer, inlet layer and skin adhesion layer, and open positioning pin holes on the corresponding layers, clean and dry them for later use; S2, cutting the microtubes by a cutting machine according to the pre-designed shape and size to obtain longitudinal outlet capillaries and longitudinal inlet capillaries, which are then cleaned and dried for later use; S3, printing the reference electrode and the working electrode on the detection layer respectively, and drop-casting the ion-sensitive material on the working electrode; S4, using the positioning devices corresponding to the positioning pin holes as the working plane, bonding the skin adhesion layer, the inlet layer, the detection layer and the microfluidic layer in sequence through the adhesive layer, installing the longitudinal inlet capillary inside the cylindrical cavity formed by the skin adhesion layer, the inlet layer, the detection layer and the microfluidic layer, and applying sealant to obtain the initial device; S5. After completing step S4, the sealing layer and the supporting layer are sequentially connected through the adhesive layer above the microfluidic layer of the initial device, and a longitudinal outlet capillary is installed inside the cylindrical cavity formed by the microfluidic layer and the sealing layer, and a sealant is applied to obtain an intermediate device; S6. A square window is opened on the support layer of the intermediate device, a sweat discharge block is installed inside the square window, and a sweat drainage port is opened on the skin adhesion layer. Finally, each layer of the structure is compressed by a press to obtain a microfluidic device for sweat collection, manipulation and ion detection.

[0017] Preferably, in step S2, the length of the longitudinal outlet capillary is equal to the sum of the thicknesses of the microfluidic layer, the sealing layer and the support layer, and the length of the longitudinal inlet capillary is equal to the sum of the thicknesses of the skin adhesion layer, the inlet layer, the detection layer and the microfluidic layer.

[0018] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: (1) The present invention avoids the use of complex processes such as traditional photolithography by adopting the cutting and lamination bonding processes, thereby significantly reducing production costs and improving production efficiency, which is conducive to large-scale replication.

[0019] (2) The simplified bonding process of the present invention ensures the precise alignment of the components with the help of a positioning device. Combined with the application of an adhesive layer and the final pressurization and tightening step, the sealing performance of the microfluidic chip is significantly improved, ensuring the stability and reliability of the fluid.

[0020] (3) The manufacturing method provided by the present invention supports automated operation and has high production efficiency, so that microfluidic devices can be produced in batches to meet commercial needs.

[0021] (4) The overall manufacturing process of the present invention is simple and high-precision, which is very suitable for extensive process production and promotes the industrialization of microfluidic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 This is a schematic diagram of the structure of a microfluidic device for human sweat collection and ion detection according to the present invention; Figure 2 A schematic diagram of the microfluidic layer structure provided for a microfluidic device for human sweat collection and ion detection according to the present invention; Figure 3 A schematic diagram of the detection layer structure provided for a microfluidic device for human sweat collection and ion detection according to the present invention; Figure 4 A schematic diagram of cutting a support layer provided for a microfluidic device for human sweat collection and ion detection according to the present invention; Figure 5 A schematic diagram of the cutting of the sealing layer provided for a microfluidic device for human sweat collection and ion detection of the present invention; Figure 6A schematic diagram of microfluidic layer cutting provided for a microfluidic device for human sweat collection and ion detection of the present invention; Figure 7 A schematic diagram of the detection layer cutting provided for a microfluidic device for human sweat collection and ion detection of the present invention; Figure 8 A schematic diagram of the inlet layer cutting provided for a microfluidic device for human sweat collection and ion detection of the present invention; Fig. 9 A schematic diagram of the cutting of the skin adhesion layer provided for a microfluidic device for human sweat collection and ion detection of the present invention; Fig.10 The present invention is a schematic diagram of the overall structure of a microfluidic device for human sweat collection and ion detection.

[0024] Description of reference numerals: 1. Sweat discharge block; 2. Support layer; 201. Square window; 3. Sealing layer; 301. First circular hole; 4. Longitudinal outlet capillary; 5. Microfluidic layer; 501. Fluid inlet; 502. Inlet channel; 503. Detection cavity; 504. Outlet channel; 505. Fluid valve; 506. Fluid outlet; 6. Detection layer; 601. Reference electrode; 602. Working electrode; 603. First connecting wire; 604. Second connecting wire; 605. First detection interface; 606. Second detection interface; 607. Second circular hole; 7. Inlet layer; 701. Third circular hole; 8. Longitudinal inlet capillary; 9. Skin adhesion layer; 901. Sweat drainage port; 10. Positioning device; 11. Positioning pin hole. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings.

[0027] like Figure 1As shown, the present invention provides a microfluidic device for human sweat collection and ion detection, comprising a sweat discharge block 1, a support layer 2, a sealing layer 3, a microfluidic layer 5, a detection layer 6, an inlet layer 7 and a skin adhesion layer 9 arranged in sequence from top to bottom, the support layer 2, the sealing layer 3, the microfluidic layer 5, the detection layer 6, the inlet layer 7 and the skin adhesion layer 9 are sequentially bonded and connected, and the layers are bonded and bonded by an adhesive layer to form a stacked structure. The overall structure is as shown in FIG. Fig.10 See Figure 4 A square window 201 is provided on the supporting layer 2, wherein the sweat discharge block 1 is embedded in the square window 201 and the lower surface is in contact with the upper surface of the sealing layer 3, a longitudinal outlet capillary 4 is provided between the sealing layer 3 and the microfluidic layer 5, and a longitudinal inlet capillary 8 is provided between the detection layer 6 and the inlet layer 7.

[0028] Reference Figure 2 A fluid inlet 501, an inlet channel 502, a detection chamber 503, an outlet channel 504, a fluid valve 505 and a fluid outlet 506 are arranged above the microfluidic layer 5. The detection chamber 503 is a streamlined structure, which is used to arrange relevant materials of ion detection objects and has the function of transferring and storing microfluidic samples, and is respectively connected to the inlet channel 502 and the outlet channel 504. The fluid inlet 501 is connected to the inlet channel 502, and the outlet channel 504 is connected to the fluid outlet 506 through the fluid valve 505. Among them, the width of the inlet channel 502 is 10~500μm, the length is 4mm, and the width is preferably 90μm; the width of the outlet channel 504 is 200~800μm, the length is 100~3000μm, and the width is preferably 500μm and the length is 600μm; the length of the detection cavity 503 is 3~15mm, the widest size is 2~6mm, and the diffusion angle at the connection between the detection cavity 503 and the end of the inlet channel 502 is 10°~75°, preferably 11.7mm in length, 3.5mm in the widest size, and 15° in diffusion angle. It should also be noted that the fluid valve 505 is used to control the fluid flow rate and flow range, and it may not be set.

[0029] Reference Figure 5 A first circular hole 301 is opened on the sealing layer 3, wherein the longitudinal outlet capillary 4 is embedded in the cylindrical cavity formed between the first circular hole 301 and the fluid outlet 506, the upper surface of the longitudinal outlet capillary 4 is in contact with the lower surface of the sweat discharge block 1, and the bottom end of the longitudinal outlet capillary 4 is arranged inside the fluid outlet 506.

[0030] Reference Figure 3The detection layer 6 is provided with a reference electrode 601 and a working electrode 602. The working electrode 602 is connected to the first detection interface 605 via a first connecting wire 603. The reference electrode 601 is connected to the second detection interface 606 via a second connecting wire 604. The first detection interface 605 and the second detection interface 606 are arranged in parallel. Figure 7 A second circular hole 607 is also provided at one end of the detection layer 6. Figure 8 As shown, a third circular hole 701 corresponding to the second circular hole 607 is provided at the inlet layer 7, and the longitudinal inlet capillary 8 is embedded in the cylindrical cavity formed by the second circular hole 607, the third circular hole 701 and the fluid inlet 501. The top of the longitudinal inlet capillary 8 passes through the second circular hole 607 and is located in the fluid inlet 501 of the microfluidic layer 5, and the bottom of the longitudinal inlet capillary 8 is arranged inside the corresponding sweat drainage port 901 below. Fig. 9 , the sweat drainage port 901 is arranged on the surface of the skin adhesion layer 9. In addition, four groups of mutually symmetrical positioning pin holes 11 are arranged on the surface of the skin adhesion layer 9, the inlet layer 7, the detection layer 6, the microfluidic layer 5, the sealing layer 3 and the support layer 2, and the positioning pin holes 11 arranged in each layer are connected to each other, and the positions of the positioning pin holes 11 are correspondingly provided with positioning devices 10, which is convenient for the assembly of the device.

[0031] In the above content, the material of the sweat discharge block 1 is paper or sponge, the support layer 2, the sealing layer 3, the microfluidic layer 5, the detection layer 6 and the inlet layer 7 are all made of a flexible material with a thickness of 10~1000μm, and the skin adhesion layer 9 is made of a flexible material with a thickness of 0.1~10mm.

[0032] The present invention also provides a method for manufacturing the above-mentioned microfluidic device, comprising the following steps: S1. Cut the flexible material substrate by a cutting machine according to the pre-designed shape and size to obtain the basic shapes of the support layer 2, the sealing layer 3, the microfluidic layer 5, the detection layer 6, the inlet layer 7 and the skin adhesion layer 9, and open positioning pin holes 11 on the corresponding layers, wash and dry them for later use; S2, cutting the microtubes by a cutting machine according to the pre-designed shape and size to obtain the longitudinal outlet capillary 4 and the longitudinal inlet capillary 8, which are then cleaned and dried for later use; S3, printing the reference electrode 601 and the working electrode 602 on the detection layer 6 respectively, and drop-casting the ion-sensitive material on the working electrode 602; S4, using the positioning devices 10 corresponding to the positioning pin holes 11 as the working plane, bonding the skin adhesion layer 9, the inlet layer 7, the detection layer 6 and the microfluidic layer 5 in sequence through the adhesive layer, installing the longitudinal inlet capillary 8 inside the cylindrical cavity formed by the skin adhesion layer 9, the inlet layer 7, the detection layer 6 and the microfluidic layer 5, and applying sealant to obtain the initial device; S5, after completing step S4, the sealing layer 3 and the supporting layer 2 are sequentially connected through the adhesive layer above the microfluidic layer 5 of the initial device, and the longitudinal outlet capillary 4 is installed inside the cylindrical cavity formed by the microfluidic layer 5 and the sealing layer 3, and the sealant is applied to obtain the intermediate device; S6. A square window 201 is opened on the support layer 2 of the intermediate device, the sweat discharge block 1 is installed inside the square window 201, and a sweat drainage port 901 is opened on the skin adhesion layer 9. Finally, each layer structure is pressed by a press to obtain a microfluidic device for sweat collection, manipulation and ion detection.

[0033] In the above steps, when the flexible material substrate is cleaned by ultrasound in step S1, anhydrous ethanol is selected as the cleaning medium, the flexible material substrate is placed in anhydrous ethanol, and ultrasonic oscillation washing is performed for 5-10 minutes, preferably 5 minutes; then dried in a room temperature environment for 5-10 minutes, optimized to 5 minutes. After drying, the PET substrate is cut by a carbon dioxide laser. At the same time, the basic shapes of the support layer 2, the sealing layer 3, the microfluidic layer 5, the detection layer 6 and the inlet layer 7 and the cutting order and path of their functional structures can be changed arbitrarily, and finally a through-flexible substrate structure is obtained. It should also be noted that in step S2, the length of the longitudinal outlet capillary 4 is equal to the sum of the thicknesses of the microfluidic layer 5, the sealing layer 3 and the support layer 2, and the length of the longitudinal inlet capillary 8 is equal to the sum of the thicknesses of the skin adhesion layer 9, the inlet layer 7, the detection layer 6 and the microfluidic layer 5.

[0034] In addition, in step S4, the specific process is as follows: first, align the positioning pin hole 11 of the skin adhesive layer 9 with the positioning pin of the positioning device 10, and place it on the table of the positioning device 10, and stick the adhesive layer on the upper surface of the skin adhesive layer 9, discharge the bubbles therein, and make the two fit together. Then, align the positioning pin hole 11 of the inlet layer 7 with the positioning pin of the positioning device 10, and stick it on the adhesive layer. Then, stick another adhesive layer on the upper surface of the inlet layer 7, discharge the bubbles therein, and make the two fit together. According to this step again, the detection layer 6, the adhesive layer and the microfluidic layer 5 are assembled and bonded together in sequence. At the same time, a longitudinal inlet capillary 8 is installed inside the cylindrical cavity formed by the skin adhesive layer 9, the inlet layer 7, the detection layer 6 and the microfluidic layer 5. The lower surface of the longitudinal inlet capillary 8 exceeds the lower surface of the inlet layer 7 and is located at the sample drainage port; the upper surface of the longitudinal inlet capillary 8 does not exceed the upper surface of the microfluidic layer 5 and is located inside the fluid inlet 501.

[0035] In step S5, the specific process is as follows: first, the adhesive layer is attached to the upper surface of the microfluidic layer 5, and the bubbles therein are discharged so that the two are attached. Then, the locating pin hole 11 of the sealing layer 3 is aligned with the locating pin of the positioning device 10, and it is attached to the surface of the adhesive layer, and the bubbles therein are discharged so that the two are attached. Then, another adhesive layer is attached to the upper surface of the sealing layer 3, and the bubbles therein are discharged so that the two are attached. Then, the locating pin hole 11 of the supporting layer 2 is aligned with the locating pin of the positioning device 10, and it is attached to the surface of the adhesive layer, and the bubbles therein are discharged so that the two are attached. At the same time, a longitudinal outlet capillary 4 is installed inside the cylindrical cavity formed by the microfluidic layer 5 and the sealing layer 3. The lower surface of the longitudinal outlet capillary 4 exceeds the lower surface of the sealing layer 3 and is located inside the fluid outlet 506; the upper surface of the longitudinal outlet capillary 4 exceeds the upper surface of the sealing layer 3, and is located inside the square window 201 of the supporting layer 2 and is connected to the sweat discharge block 1.

[0036] The present invention will be further described below through specific implementation modes.

[0037] Embodiment 1 This embodiment takes a method for manufacturing a microfluidic chip for sweat collection with a microfluidic layer 5 inlet channel width of 90 μm as an example, the flexible material substrate is 150 μm thick PET, and the preparation steps are as follows: First, according to the pre-designed shape and size, the PET flexible material matrix is ​​cut using the process parameters of 15W laser power, 660mm / s scanning speed, and 3 cutting times, respectively, to obtain the basic shapes of the support layer 2, the sealing layer 3, the microfluidic layer 5, the detection layer 6, and the inlet layer 7, as well as the functional structures and positioning pin holes 11 thereon. And then use anhydrous ethanol and an ultrasonic cleaner to clean and dry for 5 minutes; then according to the pre-designed shape and size, cut the flexible material matrix, use a blade to cut the basic shape of the skin adhesion layer 9, and use a special puncher to cut the sweat drainage port 901 on the skin adhesion layer 9, with a hole diameter of 1.5mm, to obtain the basic shape of the skin adhesion layer 9 and the functional structure thereon. Dry after cleaning; Secondly, a cutting machine is used to cut the microtube according to a preset length to obtain a longitudinal outlet capillary 4 with a length of 500 μm and a longitudinal inlet capillary 8 with a length of 1.5 mm; after washing and drying; then the positioning device 10 is used as a working plane to assemble and bond the skin adhesion layer 9, the inlet layer 7, the detection layer 6 and the microfluidic layer 5 in sequence, and the layers are bonded with an adhesive. Specifically, first align the positioning pin hole 11 of the bottom layer of the microfluidic device skin adhesion layer 9 with the positioning pin of the positioning device 10, and place it on the table of the positioning device 10, install the adhesive layer on the upper surface of the skin adhesion layer 9, and discharge the bubbles therein so that the two are bonded. Then, align the positioning pin hole 11 of the inlet layer 7 with the positioning pin of the positioning device 10, and install it on the adhesive layer. Install the adhesive layer on the upper surface of the inlet layer 77, discharge the bubbles therein, and make the two bonded. Then, according to this step, assemble and bond the detection layer 6, the adhesive layer and the microfluidic layer 5 in sequence. Subsequently, a longitudinal inlet capillary 8 is installed inside the cylindrical cavity formed by the skin adhesion layer 9, the inlet layer 7, the detection layer 6 and the microfluidic layer 5. The lower surface of the longitudinal inlet capillary 8 exceeds the lower surface of the inlet layer 7 and is located at the sweat drainage port 901; the upper surface of the longitudinal inlet capillary 8 does not exceed the upper surface of the microfluidic layer 5 and is located inside the fluid inlet 501.

[0038] Once again, using a special fixture corresponding to each positioning hole, on the microfluidic layer 5, the sealing layer 3 and the supporting layer 2 are assembled and bonded together in sequence, and each layer is bonded with an adhesive. Specifically, the bonding layer is installed on the upper surface of the microfluidic layer 5, and the bubbles therein are discharged so that the two are bonded. Then, the locating pin hole 11 of the sealing layer 3 is aligned with the locating pin of the positioning device 10, and it is installed on the surface of the bonding layer, and the bubbles therein are discharged so that the two are bonded. Then, the bonding layer is installed on the upper surface of the sealing layer 3, and the bubbles therein are discharged so that the two are bonded. Then, the locating pin hole 11 of the supporting layer 2 is aligned with the locating pin of the positioning device 10, and it is installed on the surface of the bonding layer, and the bubbles therein are discharged so that the two are bonded. In addition, a longitudinal outlet capillary 4 is installed inside the cylindrical cavity formed by the microfluidic layer 5 and the sealing layer 3. The lower surface of the longitudinal outlet capillary 4 exceeds the lower surface of the sealing layer 3 and is located inside the fluid outlet 506; the upper surface of the longitudinal outlet capillary 4 exceeds the upper surface of the sealing layer 3 and is located inside the square window 201 of the support layer 2.

[0039] Finally, the sweat discharge block 1 is installed inside the support layer 2. The longitudinal outlet capillary 4 is connected to the sweat discharge block 1. The complete microfluidic chip is placed on the operating table of the pressing device, and then a pressure of 30N is applied to press it to obtain a microfluidic device.

[0040] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A microfluidic device for human sweat collection and ion detection, characterized in that: The invention comprises a sweat discharge block, a support layer, a sealing layer, a microfluidic layer, a detection layer, an inlet layer and a skin adhesion layer which are arranged in sequence from top to bottom. The support layer, the sealing layer, the microfluidic layer, the detection layer, the inlet layer and the skin adhesion layer are sequentially bonded and connected, and each layer is bonded and bonded by an adhesive layer to form a stacked structure. A square window is provided on the support layer, and the sweat discharge block is embedded in the square window with its lower surface bonded to the upper surface of the sealing layer. A longitudinal outlet capillary is provided between the sealing layer and the microfluidic layer, and a longitudinal inlet capillary is provided between the detection layer and the inlet layer.

2. The microfluidic device for human sweat collection and ion detection according to claim 1, characterized in that: A fluid inlet, an inlet channel, a detection chamber, an outlet channel, a fluid valve and a fluid outlet are arranged above the microfluidic layer. The detection chamber is a streamlined structure, which is connected to the inlet channel and the outlet channel respectively. The fluid inlet is connected to the inlet channel, and the outlet channel and the fluid outlet are connected through a fluid valve.

3. The microfluidic device for human sweat collection and ion detection according to claim 2, characterized in that: The width of the inlet flow channel is 10~500μm and the length is 4mm, the width of the outlet flow channel is 200~800μm and the length is 100~3000μm, the length of the detection cavity is 3~15mm, the widest dimension is 2~6mm, and the diffusion angle at the connection between the detection cavity and the end of the inlet flow channel is 10°~75°.

4. The microfluidic device for human sweat collection and ion detection according to claim 2, characterized in that: The sealing layer is provided with a first circular hole, the longitudinal outlet capillary is embedded in a cylindrical cavity formed between the first circular hole and the fluid outlet, the upper surface of the longitudinal outlet capillary is in contact with the lower surface of the sweat discharge block, and the bottom end of the longitudinal outlet capillary is arranged inside the fluid outlet.

5. The microfluidic device for human sweat collection and ion detection according to claim 1, characterized in that: A reference electrode and a working electrode are arranged on the detection layer. The working electrode is connected to the first detection interface via a first connecting wire, and the reference electrode is connected to the second detection interface via a second connecting wire. The first detection interface and the second detection interface are arranged in parallel.

6. The microfluidic device for human sweat collection and ion detection according to claim 5, characterized in that: A second circular hole is also opened at one end of the detection layer, and a third circular hole corresponding to the second circular hole is arranged at the entrance layer. The longitudinal inlet capillary is embedded in a cylindrical cavity formed by the second circular hole, the third circular hole and the fluid inlet. The top end of the longitudinal inlet capillary passes through the second circular hole and is located in the fluid inlet of the microfluidic layer. The bottom of the longitudinal inlet capillary is arranged inside the corresponding sweat drainage port below, and the sweat drainage port is arranged on the surface of the skin adhesion layer.

7. The microfluidic device for human sweat collection and ion detection according to claim 1, characterized in that: The surfaces of the skin adhesion layer, the inlet layer, the detection layer, the microfluidic layer, the sealing layer and the support layer are all provided with four groups of mutually symmetrical positioning pin holes, and the positioning pin holes provided in each layer are all connected.

8. The microfluidic device for human sweat collection and ion detection according to claim 1, characterized in that: The sweat discharge block is made of paper or sponge, the support layer, sealing layer, microfluidic layer, detection layer and inlet layer are all made of flexible materials with a thickness of 10-1000 μm, and the skin adhesion layer is made of flexible materials with a thickness of 0.1-10 mm.

9. The method for manufacturing a microfluidic device for human sweat collection and ion detection according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Cut the flexible material matrix by a cutting machine according to the pre-designed shape and size to obtain the basic shapes of the support layer, sealing layer, microfluidic layer, detection layer, inlet layer and skin adhesion layer, and open positioning pin holes on the corresponding layers, clean and dry them for later use; S2, cutting the microtubes by a cutting machine according to the pre-designed shape and size to obtain longitudinal outlet capillaries and longitudinal inlet capillaries, which are then cleaned and dried for later use; S3, printing the reference electrode and the working electrode on the detection layer respectively, and drop-casting the ion-sensitive material on the working electrode; S4, using the positioning devices corresponding to the positioning pin holes as the working plane, bonding the skin adhesion layer, the inlet layer, the detection layer and the microfluidic layer in sequence through the adhesive layer, installing the longitudinal inlet capillary inside the cylindrical cavity formed by the skin adhesion layer, the inlet layer, the detection layer and the microfluidic layer, and applying sealant to obtain the initial device; S5. After completing step S4, the sealing layer and the supporting layer are sequentially connected through the adhesive layer above the microfluidic layer of the initial device, and a longitudinal outlet capillary is installed inside the cylindrical cavity formed by the microfluidic layer and the sealing layer, and a sealant is applied to obtain an intermediate device; S6. A square window is opened on the support layer of the intermediate device, a sweat discharge block is installed inside the square window, and a sweat drainage port is opened on the skin adhesion layer. Finally, each layer of the structure is compressed by a press to obtain a microfluidic device for sweat collection, manipulation and ion detection.

10. The method for manufacturing a microfluidic device for human sweat collection and ion detection according to claim 9, characterized in that: In step S2, the length of the longitudinal outlet capillary is equal to the sum of the thicknesses of the microfluidic layer, the sealing layer and the support layer, and the length of the longitudinal inlet capillary is equal to the sum of the thicknesses of the skin adhesion layer, the inlet layer, the detection layer and the microfluidic layer.

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