Micro-channel sweat sensor capable of being self-regulated and reset

Abstract

The micro-channel sweat sensor comprises a detection module, a moisture absorption layer, a hydrophobic membrane layer, a vent hole layer, a channel layer, an electrode layer and a bottom layer which are sequentially arranged from top to bottom. According to the utility model, the short-distance rectangular sweat micro-channel is designed, so that the short-distance design does not influence the detection time, and sweat enters and flows out along with the existence of the moisture absorption material and is rapidly absorbed by the moisture absorption layer material through the outlet, and the phenomenon of sweat accumulation does not exist. When a small amount of sweat passes through the flow channel, the conductivity signal can be detected, the total electrolyte concentration and the perspiration rate in the sweat can be obtained, and the accuracy and the real-time in-situ property of an experimental result are ensured. Meanwhile, a plurality of air holes and micro-flow valves are additionally arranged around the flow channel, so that the phenomenon of overflow is avoided when the liquid flows through the flow channel, and the stability of the sensor is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of wearable devices and sensors, and in particular to a micro-channel sweat sensor capable of self-regulating and resetting. Background Art

[0002] Compared with other sweat detection devices currently used to collect physical data of human motion status and vital signs, wearable sweat sensor devices can more directly and accurately judge the health status of the human body. Therefore, the research on wearable sweat sensors is one of the current development focuses in the field of wearable health electronic devices. Flexible wearable sweat sensors can continuously, real-time, and non-invasively detect sweat analytes, gain in-depth understanding of human physiology at the molecular level, and have received widespread attention for their application in personalized health monitoring.

[0003] Recent developments in soft microfluidics, multiplexed biosensing, energy harvesting devices, and materials have driven the compatibility of wearable sweat sensing platforms. Significant progress has been made in wearable sweat sensors. Wearable colorimetric and fluorescent sweat sensors provide visual sensing through the color / absorbance / fluorescence depth associated with the colorimetric / luminescent reaction between the indicator and the analyte, thereby obtaining information such as sweat volume and electrolyte concentration. However, for some applications (including worker safety, military training, and contact sports), protective equipment limits visual inspection of such equipment, so visual sweat sensors become no longer applicable. Electrochemical sensors overcome the disadvantage of requiring visual viewing and are widely used in sweat analysis by converting the target contents into current or potential signals on the surface of micro and specific electrodes. Electrochemical technology has the characteristics of high sensitivity and selectivity, and electrodes can also be flexibly designed into different shapes and sizes.

[0004] However, the current sweat sensors mainly involve the following technical challenges:

[0005] 1. The accuracy of colorimetric testing needs to be improved. Through the paper-based method combining colorimetry and optics, it can be seen from the liquid wicking equation that the flow rate attenuation caused by the resistance of the material itself cannot be overcome, and the accuracy is limited. The method combining long flow channels with colorimetry and optics is mostly used for qualitative evaluation, difficult to quantitatively measure, and has low accuracy; and the method combining long flow channels with electrical signals is difficult to avoid the problem of dual-mode signal coupling of sweat volume and concentration, affecting the accuracy of the test results. Therefore, it is necessary to find new methods to improve the accuracy of sweat sensors for sweat rate and electrolyte concentration detection results.

[0006] 2. The current sweat sensor has a short detection time. Although the scientific research field has tried to reuse it by designing a reset pump to discharge the sweat in the flow channel, the operation is cumbersome and the design of the reset pump further occupies the amount of sweat that the microchannel can accommodate. On the other hand, the long flow channel products currently available on the market are difficult to meet the long-term monitoring needs under medium and high-intensity exercise. Utility Model Content

[0007] The technical problem solved by the utility model is to provide a micro-channel sweat sensor that can be self-adjusted and reset, output an adjustable step signal through a decoupling mechanism, and use the sweat-absorbing layer material to continuously drain the sweat to achieve long-term continuous monitoring. The wireless module transmits and analyzes the data, gives human physiological signal indicators, and provides health status warnings, reasonable water and electrolyte supplementation and other suggestions. A real-time sweat signal collection, transmission, analysis and feedback system is established to achieve accurate, long-term and stable monitoring of sweat information.

[0008] The technical solution adopted by the utility model to solve its technical problems is:

[0009] A self-regulating and resetting microchannel sweat sensor comprises a detection module, a hygroscopic layer, a hydrophobic film layer, a vent layer, a channel layer, an electrode layer, a skin adhesive layer and a release film layer which are arranged in sequence from top to bottom;

[0010] The electrode layer is regularly provided with a liquid inlet for liquid inflow, a plurality of detection interdigital electrodes for signal detection, and a plurality of electrode contacts, wherein the plurality of detection interdigital electrodes for signal detection are regularly arranged around the liquid inlet and are electrically and regularly connected to the electrode contacts through leads to form detection electrode contacts;

[0011] The flow channel layer is regularly provided with a flow channel for guiding the liquid and a plurality of exhaust holes regularly arranged along both sides of the flow channel, and the head end of the flow channel is arranged directly above the liquid inlet and communicated with the liquid inlet;

[0012] The vent layer is regularly provided with an upper flow channel and a plurality of vents vertically arranged above and below the plurality of exhaust holes, the upper flow channel is arranged along the shape and size of the flow channel, the upper flow channel is arranged directly above the flow channel and is connected therewith to form a liquid micro-channel of the sensor, the liquid flows from the liquid inlet of the electrode layer into the liquid micro-channel, the liquid micro-channel guides the liquid, and flows from the head end of the liquid micro-channel to the end thereof; the liquid micro-channel is arranged directly above a plurality of finger electrodes that are periodically arranged between the detection interdigital electrodes; one or more burst valves for balancing the internal and external pressures of the liquid micro-channel are regularly arranged between the upper flow channel and the plurality of vents on the vent layer;

[0013] The hydrophobic film layer is regularly provided with a liquid outlet for the liquid to flow out and a plurality of air holes vertically arranged above and below the plurality of air holes, the liquid outlet is arranged just above the end of the liquid microchannel and is connected with the end thereof, the plurality of air holes, the plurality of air holes and the plurality of exhaust holes correspond to each other and are connected with each other;

[0014] The moisture absorbing layer is regularly fixed to the upper surface of the hydrophobic film layer through a second double-sided adhesive layer, the second double-sided adhesive layer is regularly provided with a second slot area and a second exhaust port for exhaust, the second exhaust port is connected with the second slot area and the external environment, and the second slot area avoids the liquid outlet and the area of ​​the plurality of air holes;

[0015] The detection module is regularly fixed to the upper surface of the hydrophobic film layer through a first double-sided adhesive layer and covers the hygroscopic layer. The first double-sided adhesive layer is provided with a first slot area avoiding the hygroscopic layer and a first exhaust port avoiding the second exhaust port. The first exhaust port is arranged directly above the second exhaust port and is connected thereto to form the exhaust port of the sensor device.

[0016] Furthermore, the skin adhesive layer is attached to the lower surface of the flexible substrate of the electrode layer, and the release film layer is attached to the lower surface of the skin adhesive layer; liquid inlets are regularly arranged on the skin adhesive layer, and a sweat storage chamber is formed between the skin adhesive layer and the lower surface of the flexible substrate of the electrode layer, and the liquid inlet on the electrode layer is arranged directly above the sweat storage chamber and is connected thereto.

[0017] Furthermore, the liquid microchannel adopts an opening pattern design, and the opening pattern includes but is not limited to an opening rectangular pattern, an opening circular pattern or an opening polygonal pattern.

[0018] Furthermore, the liquid microchannel is designed using an open rectangular pattern.

[0019] Furthermore, the multiple groups of detection interdigital electrodes for signal detection include a first interdigital electrode for electrolyte concentration testing and a second interdigital electrode for sweat rate testing, the first interdigital electrode is regularly arranged in front of the liquid inlet, the second interdigital electrode is regularly arranged in front of the first interdigital electrode and arranged along the shape of the liquid microfluidic channel, the finger electrodes of the first interdigital electrode are regularly arranged in front of the channel inlet of the liquid microfluidic channel, and several finger electrodes of the second interdigital electrode are regularly arranged in front of the first interdigital electrode, extending from the head end of the liquid microfluidic channel to the end of the liquid microfluidic channel.

[0020] Furthermore, the size of the vent holes on the vent hole layer is larger than the size of the vent holes on the hydrophobic membrane layer.

[0021] Furthermore, the flow channel layer, the vent layer, the hydrophobic film layer and the first double-sided adhesive tape are all regularly provided with electrode vias that avoid the plurality of electrode contacts.

[0022] Furthermore, the flow channel layer is double-sidedly adhesively treated to form a double-sided adhesive layer, and the vent layer is adhered and fixed to the electrode layer through the flow channel layer.

[0023] Furthermore, a wireless communication module is integrated in the detection module, and the self-regulating and resetting microchannel sweat sensor communicates with the circuit processing module through the wireless communication module, and transmits the electrical output signal to the circuit processing module. The signal processing circuit in the circuit processing module shapes, amplifies, filters, and performs A / D conversion on the received electrical output signal to obtain an output electrical signal of the sensor, and then converts the output electrical signal into a digital sweat monitoring parameter through the algorithm integrated in the circuit processing module.

[0024] The beneficial effects of the utility model are:

[0025] 1. The utility model provides a self-regulating and resetting microchannel sweat sensor. By designing a short-distance rectangular sweat microchannel, this short-distance design will not only not affect the detection time, but also due to the presence of hygroscopic materials, as the sweat enters and flows out, it is quickly absorbed by the hygroscopic layer material through the outlet, and there will be no sweat accumulation. When a small amount of sweat passes through the channel, the conductivity signal can be detected, and the total electrolyte concentration and sweating rate in the sweat can be obtained, ensuring the accuracy of the experimental results and real-time in-situ.

[0026] 2. The utility model provides a self-regulating and resetting micro-channel sweat sensor, which can be tested by directly sticking it to the skin surface. Currently, most products on the market need to use elastic materials or fabrics combined with sensors to make strips wrapped on the skin surface. This method increases the complexity of the sensor when used and the preparation process is lengthy.

[0027] 3. The utility model provides a self-regulating and resetting microchannel sweat sensor, which can continuously test the electrolyte concentration and sweating rate. The use of electrochemical detection avoids the visual errors caused by the colorimetric method and improves the accuracy of detection. At the same time, we add air holes and microflow valves around the flow channel to prevent overflow when the liquid flows through the flow channel, thereby ensuring the stability of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the structural explosion diagram of the utility model;

[0029] Figure 2 for Figure 1Structural diagram of the hydrophobic membrane layer;

[0030] Figure 3 for Figure 1 Structural diagram of the middle vent layer;

[0031] Figure 4 for Figure 1 Structural diagram of the mid-flow layer;

[0032] Figure 5 for Figure 1 Structural diagram of the middle electrode layer;

[0033] Figure 6 This is a schematic diagram of sensor signal detection principle of the utility model;

[0034] Figure 7 is a real-time continuous conductivity curve diagram in Example 1;

[0035] Figure 8 is a real-time continuous conductivity curve diagram in Example 2;

[0036] Fig. 9 is a real-time continuous conductivity curve diagram in Example 3;

[0037] in:

[0038] 1. Detection module, 2. Hygroscopic layer, 3. Hydrophobic film layer, 4. Ventilation hole layer, 5. Flow channel layer, 6. Electrode layer, 7. Skin glue layer, 8. Release film layer;

[0039] 11. first double-sided adhesive layer, 1101. first slot area, 1102. first exhaust port, 1103. first electrode via hole;

[0040] 12. second double-sided adhesive layer, 1201. second slot area, 1202. second exhaust port;

[0041] 301, liquid outlet, 302, air vent;

[0042] 401, upper flow channel, 402, burst valve, 403, vent hole;

[0043] 501, flow channel inlet, 502, flow channel, 503, exhaust hole;

[0044] 60, electrode via, 601, liquid inlet, 602, detection interdigital electrode, 6021, first interdigital electrode, 6022, second interdigital electrode, 603, electrode contact, 6031, electrolyte concentration test electrode contact, 6032, sweat rate test electrode contact, 6033, power supply electrode contact;

[0045] 701. Sweat storage chamber. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0048] like Figure 1-5 As shown, the utility model provides a microchannel sweat sensor with self-regulating and resetting properties, comprising a detection module 1, a hygroscopic layer 2, a hydrophobic membrane layer 3, a vent layer 4, a channel layer 5, an electrode layer 6, a skin adhesive layer 7 and a release film layer 8, which are arranged in sequence from top to bottom.

[0049] Among them, the detection module 1 is used to collect the corresponding electrical output signal of the sensor, and is electrically connected to a number of electrode contacts on the surface of the electrode layer 6 to power the interdigital electrodes on the surface of the electrode layer, and collect the conductivity changes in the interdigital electrode circuit (and the electrical output signal of the sensor) and transmit them to the circuit processing module. The signal processing circuit in the circuit processing module shapes, amplifies, filters, and A / D converts the received electrical output signal (analog signal) to obtain the output electrical signal (digital signal) of the sensor, and then converts the output electrical signal into a digital sweat monitoring parameter through the algorithm integrated in the circuit processing module.

[0050] Furthermore, the detection module internally integrates a DAC reference voltage generation unit, a voltage conversion unit, an AFE small signal acquisition unit and a wireless communication unit. The wireless communication module wirelessly communicates with the circuit processing module, transmits the electrical output signal to the circuit processing module, and the signal processing circuit in the circuit processing module shapes, amplifies, filters, and performs A / D conversion on the received electrical output signal (analog signal) to obtain the output electrical signal (digital signal) of the sensor, and then converts the output electrical signal into a digital sweat monitoring parameter through the algorithm integrated in the circuit processing module.

[0051] The above-mentioned circuit processing module and wireless communication module can be integrated into the detection module. Among them, the wireless communication module preferably uses low-power Bluetooth communication as wireless communication.

[0052] like Figure 1 As shown, further, the detection module 1 is bonded and fixed to the upper surface of the hydrophobic film layer 3 through the first double-sided adhesive layer 11, and covers the hygroscopic layer 2. The hygroscopic layer 2 is also bonded and fixed to the upper surface of the hydrophobic film layer 3 through the second double-sided adhesive layer 12, and is covered by the detection module 1.

[0053] The material of the hygroscopic layer 2 is any one of paper, cloth, sponge, etc. or a combination of multiple materials with hygroscopic properties, including but not limited to any one of non-woven fabrics, toilet paper, dust-free paper, sweat-absorbing stickers, etc. or a combination of multiple materials. In order to extend the service life of the sensor, we use one or more layers of water-absorbing materials to quickly absorb the sweat discharged from the flow channel.

[0054] The size of the moisture absorbing layer 2 is no larger than 30 mm×30 mm, and the thickness is no larger than 1 mm. Preferably, the size is 15 mm×24 mm, and the thickness is 800 um.

[0055] like Figure 5 As shown, it is a structural diagram of the electrode layer 6. The electrode layer 6 includes a flexible substrate, on which a liquid inlet 601 for sweat to flow in, a plurality of detection interdigital electrodes 602 for signal detection, and a plurality of electrode contacts 603 are provided. A plurality of detection interdigital electrodes for signal detection are regularly arranged in front of the liquid inlet 601, including a first interdigital electrode 6021 for electrolyte concentration test / detection and a second interdigital electrode 6022 for sweat rate test / detection. The first interdigital electrode 6021 and the second interdigital electrode 6022 are respectively connected to the corresponding electrode contacts 603 through electrode wires arranged on the flexible substrate to form electrolyte concentration test electrode contacts 6031 and sweat rate test electrode contacts 6032, respectively. Further, the electrode contacts 603 also include power supply electrode contacts 6033 for power supply.

[0056] Furthermore, the flexible substrate uses a thin film electrode, and the thin film material can be polyimide, polydimethylsiloxane or polyethylene terephthalate. The detection interdigital electrode is a conductivity electrode, and the conductivity electrode material can be carbon nanotubes, graphene, carbon black or carbon fiber.

[0057] Among them, the liquid inlet 601 is used for the inflow of liquid such as sweat. The liquid is drained by the flow channel layer 5 and flows through the first interdigital electrode and the second interdigital electrode respectively, thereby realizing simultaneous detection of electrolyte concentration and sweating rate through the first interdigital electrode 6021 and the second interdigital electrode 6022.

[0058] When liquid enters the first interdigitated electrode 6021, because the electrolyte concentration contained in the liquid is different, the conductivity is different, and different electrical signals can be output, thereby detecting the electrolyte concentration in the liquid. When liquid enters the second interdigitated electrode 6022, because the second interdigitated electrode is provided with a number of equally spaced finger electrodes, the liquid sequentially connects the several finger electrodes in the second interdigitated electrode in sequence, causing the conductivity in the circuit to change, generating a step signal, and different flow rates have different time for the step signal to occur, thereby detecting the liquid flow rate (i.e., sweat rate).

[0059] Further, such as Figure 5 As shown, the electrode contact 603 is regularly arranged on one side of the electrode layer 6, the liquid inlet 601 is regularly arranged in the middle position of the electrode layer 6, the first interdigitated electrode 6021 is regularly arranged in front of the liquid inlet, and the second interdigitated electrode 6022 is regularly arranged in front of the first interdigitated electrode.

[0060] In one embodiment, if Figure 5 As shown, there are six electrode contacts, which are arranged in the middle and right side of the electrode layer 6, and are formed into six electrode contacts A, B, C, D, E, and F from top to bottom. Among them, the wire between the first interdigitated electrode 6021 and the electrolyte concentration test electrode contact 6031 is the first interdigitated electrode wire, which bypasses the liquid inlet 601 and is electrically connected to the electrode contacts B and C to form the electrolyte concentration test electrode contact 6031. The wire between the second interdigitated electrode 6022 and the sweat rate test electrode 6032 is the second interdigitated electrode wire, which is arranged on the periphery of the first interdigitated electrode wire, bypasses the first interdigitated electrode wire and is electrically connected to the electrode contacts A and D to form the sweat rate test electrode 6032. Electrode contacts E and F serve as power supply electrode contacts 6033.

[0061] like Figure 4 As shown, it is a structural diagram of the flow channel layer 5. The flow channel 502 is regularly arranged on the flow channel layer 5, and the head end of the flow channel 502 is provided with a flow channel inlet 501 for convenient liquid entry, and the flow channel inlet 501 is vertically arranged just above the liquid inlet 601 on the electrode layer and connected thereto. The sweat liquid flows from the liquid inlet on the electrode layer into the flow channel inlet 501 in the flow channel layer 5, and flows from the head end of the flow channel 502 to the end thereof through the flow diversion of the flow channel 502. Therefore, in order to generate a step signal, the shape of the second interdigital electrode 6022 is regularly arranged along the shape and flow direction of the flow channel 502, and is arranged just below the flow channel 502; in other words, the shape of the flow channel 502 is regularly arranged along the shape of the second interdigital electrode 6022, and is arranged just above the second interdigital electrode 6022. When the liquid flows into the flow channel 502 from the liquid inlet 601, the liquid sequentially connects the finger-shaped electrodes with periodic regularity between the second interdigital electrodes, and sequentially electrically connects them, thereby generating a step signal.

[0062] Furthermore, a plurality of exhaust holes 503 are regularly arranged on the left and right sides of the flow channel 502 along the shape and flow direction of the flow channel.

[0063] Further, in one embodiment, if Figure 4 As shown, the flow channel 502 adopts an open rectangular graphic design, which can greatly reduce the volume and size of the sensor. Of course, in other embodiments, an open polygonal graphic design or an open circular graphic design, or other regular open graphic designs can also be adopted.

[0064] Furthermore, the side length of the flow channel layer 5 is not greater than 30 mm×30 mm, and the thickness is 50-200 um. Preferably, the best effect is achieved when the side length is 30 mm×30 mm and the thickness is 100 um.

[0065] like Figure 3 As shown, it is a structural diagram of the vent layer 4. The vent layer 4 is regularly provided with an upper flow channel 401 and a plurality of vents 403. The upper flow channel 401 is arranged along the shape of the flow channel 502, and is arranged directly above the flow channel 502 and is connected thereto. The upper flow channel 401 and the flow channel 502 together constitute the micro-flow channel of the sensor of the utility model. The plurality of vents 403 are regularly arranged on the left and right sides of the upper flow channel 401, and correspond one to one with the plurality of exhaust holes 503, and are regularly arranged directly above the plurality of exhaust holes 503 and are connected thereto one by one.

[0066] Furthermore, one or more microfluidic valves 402 (i.e., burst valves, breakthrough valves) are provided between the plurality of vents 403 and the upper flow channel 401. The microfluidic valves 402 can ensure the pressure balance inside and outside the microchannel, thereby achieving stable separation and self-regulating reset of sweat.

[0067] The capillary pressure difference ΔPa (i.e., breakthrough pressure) inside and outside the curved liquid surface at the front end of the liquid in the rectangular channel satisfies Young's equation:

[0068]

[0069] Where σ is the surface tension of the liquid, θ A is the contact angle in the vent channel, θ I =min{θ A +β, 180°}, β is the divergence angle of the stop valve, w and h are the width and height of the divergent part of the vent hole respectively.

[0070] like Figure 3As shown, the rectangular flow channel opening upward is the main microchannel, and the flow channel between the main microchannel and a plurality of vents 403 is a flow channel branch. When the bursting valve 402 is not provided in the flow channel branch, we call the vent a valveless vent; when the bursting valve 402 is provided in the flow channel branch, we call the vent a valved vent.

[0071] The ΔPa of the main microchannel is calculated as follows:

[0072] Knowing that the contact angle is 81°, the width and height are 0.75mm and 400um respectively, and the surface tension of water is 73mN / m, the ΔPa is -0.086kPa. The calculation method of ΔPa in the main microchannel is similar when there is a valveless vent and a valved vent. When there is a stop valve, the angle of the stop valve needs to be added to the contact angle.

[0073] Therefore, through calculation, it can be obtained that the ΔPa in the main microchannel is -0.097kPa, the ΔPa of the valveless vent is -0.254kPa, and the ΔPa of the valved vent is 0.937kPa. From the breakthrough pressure calculation results, it can be seen that when there is no vent, the breakthrough pressure in the main microchannel is the smallest. When there is a burst valve, it can provide a larger breakthrough pressure in the main microchannel, thereby preventing the liquid from leaking out. At the same time, it ensures that during the liquid flow separation process, the air flow can enter from the vent, which can ensure the pressure balance inside and outside the main microchannel, and achieve stable separation and self-regulating reset of sweat.

[0074] Furthermore, the side length of the vent layer is not greater than 30mm×30mm, and the thickness is 50-200um. Preferably, the best effect is achieved when the side length is 30mm×30mm and the thickness is 60um. At the same time, the shape of the vent 403 is not limited, and can be square, diamond, circular, polygonal, etc., with a side length of not greater than 500um×500um or a diameter of not greater than 500um, forming multiple micro-holes and the overall size is larger than the size of the vent on the hydrophobic membrane layer 3.

[0075] like Figure 2 , which is a structural diagram of the hydrophobic membrane layer 3. The hydrophobic membrane layer 3 is regularly provided with liquid outlets 301 for liquid outflow and a plurality of air holes 302 for ventilation to maintain pressure balance. The function of these air holes and the hydrophobicity of the material is to allow the liquid in the sensor to overcome less resistance when flowing through the microchannel, and to keep the pressure difference inside and outside the microchannel at the lowest state, thereby ensuring that the sweat liquid can flow along the main microchannel.

[0076] Among them, the liquid outlet 301 is regularly arranged at the end of the microchannel, that is, it is regularly arranged just above the end of the upper channel 401 on the vent layer and connected thereto. The sweat liquid flows from the liquid inlet 601 of the electrode layer into the microchannel formed on the channel layer 5 and the vent layer 4, and flows out from the liquid outlet 301 on the hydrophobic membrane layer 3 to the hygroscopic layer 2, and is absorbed by the hygroscopic layer. The liquid inlet 601 is arranged at the head end of the microchannel as the inlet of the microchannel, and the liquid outlet 301 is arranged at the end of the microchannel as the outlet of the microchannel. A plurality of vents 302 correspond to a plurality of vents 403 on the vent layer 4 one by one, and are regularly arranged just above a plurality of vents 403 and connected thereto one by one. The vents 403 are connected to the outside through the vents 302, and the air flow can enter the vents from the vents, thereby ensuring the pressure balance inside and outside the main microchannel, and realizing the stable separation and self-regulating reset of sweat.

[0077] Furthermore, the size of the vent 403 on the vent layer 4 is larger than the size of the vent 302 on the hydrophobic membrane layer 3 .

[0078] Furthermore, the material of the hydrophobic film layer includes but is not limited to any one of polyimide (PI), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE). Among them, the side length of the hydrophobic film layer is not greater than 30mm×30mm, and the thickness is 30-200um. Preferably, the size of the hydrophobic film layer is 30mm×30mm, and the thickness is 100um for the best effect. The shape of the air permeable holes 302 on the surface of the hydrophobic film layer is not limited, and can be square, diamond, circular, polygonal, etc., with a side length of not more than 300um×300um or a diameter of not more than 300um, forming a plurality of micropores.

[0079] like Figure 6 As shown in the figure, the working principle of the self-regulating and resetting microfluidic channel sweat sensor of the utility model is shown. The principle mainly involves the equally spaced interdigitated electrodes in the microfluidic channel, which will synchronize the fluid flow channel position to generate a conductivity step signal, so as to calculate its flow rate and volume according to the time of the signal mutation. When the liquid fills the microfluidic channel, it will be absorbed by the hygroscopic layer at the liquid outlet. The self-regulating and resetting sweat sensor is different from other droplet separation detection methods and does not need to ensure the consistency of the droplet volume each time it is separated. Changes in the water absorption properties of the sweat absorption layer and the influence of external disturbances will cause the liquid flow to separate at different positions, such as positions 4, 5, and 6 in the figure, but new conductivity step signals can continue to be generated from the disconnection point, realizing continuous monitoring of the sweat signal with self-regulation and resetting.

[0080] like Figure 1-5As shown, in order to facilitate the electrical connection between the detection module 1 and the electrode layer 6, a number of electrode vias 60 are regularly arranged at the same positions of the hydrophobic membrane layer 3, the vent layer 4 and the flow channel layer 5 along the positions of the electrode contacts 603 on the electrode layer 6, thereby facilitating the electrical connection between the wires or pins or spherical pins on the detection module and the electrode contacts on the electrode layer.

[0081] Further, such as Figure 1 As shown, the detection module 1 is adhered to the upper surface of the hydrophobic film layer 3 through the first double-sided adhesive layer 11. In order to avoid and reduce the influence of the first double-sided adhesive layer on the liquid absorption function of the hygroscopic layer 2 and avoid affecting the gas exchange in the microchannel, the first double-sided adhesive layer 11 is provided with a first slot area 1101 avoiding the hygroscopic layer 2 and a first exhaust port 1102 connected to the outside.

[0082] Furthermore, in order to facilitate the electrical connection between the detection module and the electrode contacts on the electrode layer, the first double-sided adhesive layer 11 is further provided with a first electrode via 1103 that avoids the contact connection.

[0083] Furthermore, the hygroscopic layer 2 is also adhered to the upper surface of the hydrophobic film layer 3 through the second double-sided adhesive layer 12. In order to minimize the influence of the second double-sided adhesive layer on the liquid absorption function of the hygroscopic layer as much as possible, and to ensure that a gap is reserved between the sweat hygroscopic layer and the hydrophobic film layer to establish a gas exchange channel, during the droplet separation process in the microchannel, ensure that the external airflow can enter the microchannel through the air holes and vents to balance the internal and external air pressure of the microchannel, the second double-sided adhesive layer 12 is also provided with a second slot area 1201 and a second exhaust port 1202 that avoid the microchannel and the plurality of air holes 302 areas.

[0084] Furthermore, in order to maintain the pressure balance inside and outside the microchannel, the first double-sided adhesive layer 11 and the second double-sided adhesive layer 12 are respectively provided with a first exhaust port 1102 and a second exhaust port 1202. The second exhaust port 1102 connects the second slot area 1201 with the external environment, and the first exhaust port 1102 is arranged directly above the second exhaust port 1202 and together with the second exhaust port 1202, constitutes the exhaust port of the sensor, so that the gas exchange inside the microchannel is facilitated to maintain the pressure balance inside and outside the microchannel through the connection between the exhaust port and the external environment.

[0085] like Figure 1 As shown, the skin adhesive layer 7 is arranged on the lower surface of the flexible substrate of the electrode layer 6, and is used to attach the microchannel sweat sensor of the utility model to human skin. The skin adhesive layer 7 uses low-sensitivity glue as the skin adhesive layer.

[0086] Furthermore, a liquid inlet is provided at the middle position of the skin adhesive layer 7 to form a sweat storage chamber 701, and the liquid inlet 601 on the electrode layer is provided directly above the sweat storage chamber 701 and communicated therewith.

[0087] Furthermore, the diameter of the sweat storage chamber is 3-8 mm, and the height is 100-200 um. Preferably, the best effect is achieved when the diameter is 5 mm and the height is 100 um.

[0088] Furthermore, a release film 8 is provided at the bottom of the skin adhesive layer 7 to protect the low-sensitivity adhesive. Before use, one only needs to tear off the release film and stick it on the skin surface for normal testing.

[0089] Embodiment 1:

[0090] This embodiment provides a micro-channel sweat sensor device that can self-regulate and reset. Figure 1 As shown, it includes: a detection module, a first double-sided adhesive layer, a moisture absorption layer, a second double-sided adhesive layer, a hydrophobic film layer, a vent layer, a flow channel layer, an electrode layer, a skin adhesive layer and a release film layer.

[0091] Among them, the hydrophobic film layer and the detection module are fixedly connected by the first double-sided adhesive layer, the hygroscopic layer and the hydrophobic film layer are fixedly connected by the second first double-sided adhesive layer, and the hygroscopic layer material is toilet paper. The flow channel layer is made of double-sided adhesive material (polyimide (PI), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE)), and the vent layer is also a flexible substrate connected to the upper surface of the flow channel layer, and the hole positions correspond in the vertical direction, forming a microchannel for sweat. The electrode layer uses PI as a flexible substrate and copper as a wire electrode, which is connected to the lower surface of the flow channel layer. The sensitive skin glue is made of double-sided adhesive material, and a through hole is cut by laser as a sweat storage chamber.

[0092] When used specifically, the wearable sweat sensor device in this embodiment is attached to the skin epidermis, and sweat is secreted from the sweat glands to the skin epidermis and then enters the sensor. When a certain period of time has passed and the sweat fills the entire storage chamber and enters the flow channel layer, a signal is generated. The continuous conductivity value of the sweat is recorded in real time through the small detection module, forming a signal such as Figure 7 The real-time continuous conductivity curve is shown. When the conductivity curve signal begins to drop suddenly, it indicates that the sweat secreted by human skin passes through the entire flow channel moisture absorption layer and the toilet paper begins to absorb excess sweat. After absorbing part of the sweat, the test is repeated and a step-like conductivity signal is generated again. Therefore, the toilet paper has a good performance as a sweat-absorbing material.

[0093] Embodiment 2:

[0094] This embodiment provides a micro-channel sweat sensor device that can self-regulate and reset. Figure 1 As shown, it includes: a detection module, a first double-sided adhesive layer, a moisture absorption layer, a second double-sided adhesive layer, a hydrophobic film layer, a vent layer, a flow channel layer, an electrode layer, a skin adhesive and a release film.

[0095] The moisture absorbing layer material is dust-free paper, and other materials are selected from the materials in Example 1.

[0096] When used specifically, the wearable sweat sensor device in this embodiment is attached to the skin epidermis, and sweat is secreted from the sweat glands to the skin epidermis and then enters the sensor. When a certain period of time has passed and the sweat fills the entire storage chamber and enters the flow channel layer, a signal is generated. The continuous conductivity value of the sweat is recorded in real time through the small detection module, forming a signal such as Figure 8 The real-time continuous conductivity curve is shown. When the conductivity curve signal begins to drop suddenly, it indicates that the sweat secreted by human skin passes through the entire flow channel and the hygroscopic layer toilet paper begins to absorb excess sweat. After absorbing some sweat, the test is repeated and a step-like conductivity signal is generated again. Therefore, dust-free paper can also be used as a hygroscopic layer material.

[0097] Embodiment 3:

[0098] This embodiment provides a micro-channel sweat sensor device that can self-regulate and reset. Figure 1 As shown, it includes: a detection module, a first double-sided adhesive layer, a moisture absorption layer, a second double-sided adhesive layer, a hydrophobic film layer, a vent layer, a flow channel layer, an electrode layer, a skin adhesive and a release film.

[0099] The moisture absorbing layer material is sweat-absorbing cloth, and other materials are selected from the materials in Example 1.

[0100] When used specifically, the wearable sweat sensor device in this embodiment is attached to the skin epidermis, and sweat is secreted from the sweat glands to the skin epidermis and then enters the sensor. When a certain period of time has passed and the sweat fills the entire storage chamber and enters the flow channel layer, a signal is generated. The continuous conductivity value of the sweat is recorded in real time through the small detection module, forming a signal such as Fig. 9 The real-time continuous conductivity curve is shown. When the conductivity curve signal begins to drop suddenly, it indicates that the sweat secreted by human skin begins to absorb excess sweat through the entire hydrophilic flow channel. After part of the sweat is absorbed, the test is repeated, and a step-like conductivity signal is generated again. However, the flatness and liquid transfer ability of the hydrophilic fabric are poor. Therefore, the experiment cannot absorb excess sweat to a certain extent, so the test is terminated.

[0101] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microchannel sweat sensor capable of self-regulation and resetting, characterized in that: It includes a detection module, a moisture absorption layer, a hydrophobic film layer, a vent layer, a flow channel layer, an electrode layer, a skin adhesive layer and a release film layer which are arranged in sequence from top to bottom; The electrode layer is regularly provided with a liquid inlet for liquid inflow, a plurality of detection interdigital electrodes for signal detection, and a plurality of electrode contacts, wherein the plurality of detection interdigital electrodes for signal detection are regularly arranged around the liquid inlet and are electrically and regularly connected to the electrode contacts through leads to form detection electrode contacts; The flow channel layer is regularly provided with a flow channel for guiding the liquid and a plurality of exhaust holes regularly arranged along both sides of the flow channel, and the head end of the flow channel is arranged directly above the liquid inlet and communicated with the liquid inlet; The vent layer is regularly provided with an upper flow channel and a plurality of vents vertically arranged up and down along the plurality of exhaust holes, the upper flow channel is arranged along the shape and size of the flow channel, the upper flow channel is arranged directly above the flow channel and is connected therewith to form a liquid micro-channel of the sensor, the liquid flows from the liquid inlet of the electrode layer into the liquid micro-channel, the liquid micro-channel guides the liquid, and flows from the head end of the liquid micro-channel to the end thereof; The liquid microchannel is arranged directly above a plurality of finger electrodes arranged periodically between the detection interdigital electrodes; one or more burst valves for balancing the internal and external pressures of the liquid microchannel are regularly arranged between the upper channel and the plurality of vents on the vent layer; The hydrophobic film layer is regularly provided with a liquid outlet for the liquid to flow out and a plurality of air holes vertically arranged above and below the plurality of air holes, the liquid outlet is arranged just above the end of the liquid microchannel and is connected with the end thereof, the plurality of air holes, the plurality of air holes and the plurality of exhaust holes correspond to each other and are connected with each other; The moisture absorbing layer is regularly fixed to the upper surface of the hydrophobic film layer through a second double-sided adhesive layer, the second double-sided adhesive layer is regularly provided with a second slot area and a second exhaust port for exhaust, the second exhaust port is connected with the second slot area and the external environment, and the second slot area avoids the liquid outlet and the area of ​​the plurality of air holes; The detection module is regularly fixed to the upper surface of the hydrophobic film layer through a first double-sided adhesive layer and covers the hygroscopic layer. The first double-sided adhesive layer is provided with a first slot area avoiding the hygroscopic layer and a first exhaust port avoiding the second exhaust port. The first exhaust port is arranged directly above the second exhaust port and is connected thereto to form the exhaust port of the sensor device.

2. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 1, characterized in that: The skin adhesive layer is attached to the lower surface of the flexible base of the electrode layer, and the release film layer is attached to the lower surface of the skin adhesive layer; liquid inlets are regularly arranged on the skin adhesive layer, and a sweat storage chamber is formed between the skin adhesive layer and the lower surface of the flexible base of the electrode layer, and the liquid inlet on the electrode layer is arranged directly above the sweat storage chamber and is connected with it.

3. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 1, characterized in that: The liquid microchannel adopts an opening pattern design, and the opening pattern includes an opening rectangular pattern, an opening circular pattern or an opening polygonal pattern.

4. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 3, characterized in that: The liquid microchannel is designed using an open rectangular pattern.

5. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 1, characterized in that: The multiple groups of detection interdigital electrodes for signal detection include a first interdigital electrode for electrolyte concentration testing and a second interdigital electrode for sweat rate testing, the first interdigital electrode is regularly arranged in front of the liquid inlet, the second interdigital electrode is regularly arranged in front of the first interdigital electrode and arranged along the shape of the liquid microfluidic channel, the finger electrodes of the first interdigital electrode are regularly arranged in front of the channel inlet of the liquid microfluidic channel, and several finger electrodes of the second interdigital electrode are regularly arranged in front of the first interdigital electrode, extending from the head end of the liquid microfluidic channel to the end of the liquid microfluidic channel.

6. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 1, characterized in that: The size of the vent holes on the vent hole layer is greater than the size of the vent holes on the hydrophobic membrane layer.

7. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 1, characterized in that: The flow channel layer, the vent layer, the hydrophobic film layer and the first double-sided adhesive tape are all regularly provided with electrode vias to avoid the plurality of electrode contacts.

8. The micro-channel sweat sensor capable of self-regulation and resetting as claimed in claim 1, characterized in that: The double-sided adhesive treatment of the flow channel layer forms a double-sided adhesive layer, and the vent layer is adhered and fixed to the electrode layer through the flow channel layer.

9. A micro-channel sweat sensor capable of self-regulation and resetting according to any one of claims 1 to 8, characterized in that: A wireless communication module is integrated in the detection module, and the self-regulating and resetting microfluidic channel sweat sensor communicates with the circuit processing module through the wireless communication module, and transmits the electrical output signal to the circuit processing module. The signal processing circuit in the circuit processing module shapes, amplifies, filters, and performs A / D conversion processing on the received electrical output signal to obtain the output electrical signal of the sensor, and then converts the output electrical signal into a digital sweat monitoring parameter through the algorithm integrated in the circuit processing module.

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