Flexible wearable dual-channel sweat sensing device and preparation method therefor

Abstract

The present invention relates to a flexible wearable dual-channel sweat sensing device and a preparation method therefor. The device comprises: a detection module and a sweat sensor patch. The detection module is electrically connected to the sweat sensor patch regularly by means of a pluggable interface or a thimble pogo pin to collect electrical conductance signals from the sweat sensor patch and convert the electrical conductance signals into electrolyte concentration information and sweat volume information / sweating rate information. The flexible wearable sweat sensor device provided by the present invention is provided with a sweat channel of a certain length, enabling detection of sweat volume and electrolyte concentration within the sweat channel. The device has a simple manufacturing process, requiring only straightforward bonding to complete the fabrication of a sensor patch. The detection by the flexible wearable sweat sensor device provided by the present invention is based on the electrical conductance principle. Therefore, by means of electrical conductance curves, the sensor achieves real-time continuous monitoring of sweat volume and electrolyte concentration. Additionally, after the sweat is discharged from the flow channel, the sensor can be reused because it is not a disposable consumable.

Description

A flexible wearable dual-channel sweat sensor device and its preparation method Technical Field

[0001] The present invention relates to the technical field of wearable devices and sensors, and in particular to a flexible wearable dual-channel sweat sensor device and a preparation method thereof. Background Art

[0002] Monitoring the body's physical and chemical signals is crucial for preventing disease, especially chronic illnesses. However, efficient, continuous, real-time, and non-invasive monitoring of the human body remains a challenge. Sweat carries substances that are closely related to the body's physiological state. Therefore, developing non-invasive, wearable sweat sensors is an important approach for accurately and real-time detection and analysis of these biomarkers.

[0003] As an important biological fluid for real-time health monitoring, sweat carries a large number of substances that transmit human physiological information, such as metabolites (glucose, lactate), electrolytes (Na+, Cl-, K+), and hormones (cortisol, dopamine (DA)). Various physiological indicators in sweat can effectively reflect an individual's physical health status. For example, sodium ion detection can provide a timely warning of hyponatremia (serum sodium <135mmol / L); cortisol can reflect stress conditions, etc. Compared with other biological fluids of the human body (blood, tissue fluid, tears, urine, saliva, etc.), sweat plays an important physiological role in body temperature regulation, immune defense, electrolyte and pH balance, etc. because it is easy to obtain and can be monitored non-invasively. It has been identified as an important indicator for human health monitoring. In order to maintain the body's hydration balance during the continuous sweating process, a personalized rehydration strategy needs to be customized according to individual conditions. Sweating rate detection can provide a key basis for the formulation of rehydration strategies.

[0004] Colorimetric, hydrogel swelling, capacitive, and impedance-based methods have been used to detect sweating rate. These methods can all perform in situ detection, but they also have some shortcomings.

[0005] 1. Colorimetric and hydrogel swelling detection methods require continuous acquisition of optical images and image analysis to obtain sweating rate information, which is not convenient for automatic detection. Measurement methods based on electrical signals can achieve real-time automatic monitoring.

[0006] 2. Impedance-based measurement methods convert the sweat volume within a microfluidic channel into the impedance of a sensing electrode. Continuous impedance-based sweat rate sensors can provide real-time sweat rate information based on electrode impedance. However, changes in electrolyte concentration can significantly affect electrode impedance, necessitating correction of the results.

[0007] Wearable flexible sweat sensors can detect sweat rate and electrolyte concentration in real time and in situ, greatly facilitating people's lives. However, the current preparation methods of sweat sensors are relatively cumbersome and complicated, which undoubtedly increases the cost of the sensors and narrows the target audience.

[0008] Summary of the Invention

[0009] The technical problem solved by the present invention is to provide a reusable, flexible, wearable dual-channel sweat sensor device with a simple preparation process.

[0010] The technical solution adopted by the present invention to solve its technical problem is:

[0011] A flexible wearable dual-channel sweat sensing device comprises: a detection module and a sweat sensor patch. The detection module is electrically connected to the sweat sensor patch via a plug-in interface or a thimble-type spring pin to collect a conductivity signal from the sweat sensor patch and convert the conductivity signal into electrolyte concentration information and sweat volume information / sweating rate information.

[0012] The detection module internally integrates a reference voltage generation unit, a voltage conversion unit, an AFE small signal acquisition unit and a wireless communication unit;

[0013] The sweat sensor patch includes a hydrophobic membrane layer, a flow channel layer, an electrode layer and a bottom layer regularly arranged from top to bottom;

[0014] The bottom layer includes a skin adhesive layer for adhering to human skin and is arranged on the lower surface of the flexible substrate of the electrode layer. Regular openings are arranged on the bottom layer, and a sweat receiving chamber is formed between the bottom layer and the flexible substrate of the electrode layer;

[0015] The electrode layer includes the flexible substrate and a plurality of detection interdigital electrodes for testing regularly arranged on the upper surface of the flexible substrate, a liquid inlet is provided on the flexible substrate, the plurality of interdigital electrodes are regularly arranged in front of the liquid inlet, and are regularly connected to a plurality of electrode contacts through leads provided on the flexible substrate to form detection electrode contacts;

[0016] The flow channel layer is regularly provided with flow channels, which are regularly arranged along the shapes of the plurality of detection interdigital electrodes and are arranged directly above the plurality of finger-shaped electrodes between the plurality of detection interdigital electrodes, so as to place the plurality of finger-shaped electrodes between the plurality of detection interdigital electrodes in the flow channel; the front end and the end of the flow channel are respectively provided with a flow channel inlet for sweat to flow in and a flow channel outlet for sweat to flow out, the flow channel inlet being connected to the sweat receiving chamber through the liquid inlet, and the flow channel outlet leading out of the flow channel layer and communicating with the outside world;

[0017] The hydrophobic film layer is attached to the upper surface of the flow channel layer to encapsulate the flow channels in the flow channel layer.

[0018] Furthermore, the base of the flow channel layer is made of a hydrophobic material, and the bends of the flow channel are rounded to form a hydrophobic flow channel.

[0019] Furthermore, the plurality of detection interdigital electrodes include a first interdigital electrode for electrolyte concentration testing and a second interdigital electrode for sweat amount / sweating rate testing, and the first interdigital electrode and the second interdigital electrode are regularly arranged in front of the liquid inlet; the second interdigital electrode is S-shaped and covers the flexible substrate as much as possible, and the second interdigital electrodes are regularly arranged along the left and right sides of the liquid inlet.

[0020] Furthermore, the second interdigital electrodes on the left and right sides of the liquid inlet are arranged with equal distances and lengths on both sides of the liquid inlet to cover both sides of the flexible substrate as much as possible.

[0021] Furthermore, electrode vias are regularly arranged on the flow channel layer and the hydrophobic membrane layer just above the plurality of electrode contacts to facilitate electrical connection between the detection module and the electrode layer.

[0022] Furthermore, the detection module is adhered to the upper surface of the hydrophobic film layer through a double-sided adhesive layer.

[0023] Furthermore, electrode vias are regularly arranged on the double-sided adhesive layer directly above the plurality of electrode contacts.

[0024] Furthermore, the sweat sensor patch is a flexible structure, and the detection module is a rigid structure.

[0025] Furthermore, the flexible substrate of the electrode layer is a thin film electrode, and the plurality of detection interdigital electrodes are conductivity electrodes.

[0026] A method for preparing a flexible wearable dual-channel sweat sensor device comprises the following steps:

[0027] Step S1: preparing an electrode layer by etching copper or nickel-gold on a flexible substrate to obtain a plurality of detection interdigital electrodes, a plurality of electrode contacts, and electrode leads regularly connecting the plurality of detection interdigital electrodes and the plurality of electrode contacts, and cutting a liquid inlet on the electrode layer using a laser;

[0028] Step S2: preparing a flow channel layer, cutting the flow channel shape along the shape of the plurality of detection interdigital electrodes by laser, cutting the electrode vias along the shape of the plurality of electrode contacts, designing a flow channel inlet at the front end of the flow channel that is connected to the liquid inlet, and leading the outlet at the end of the flow channel out of the flow channel layer, setting rounded corners at the bends of the flow channel, and adhering the upper and lower surfaces of the flow channel to the upper surface of the electrode layer with adhesive, or adhering to the upper surface of the electrode layer with double-sided tape;

[0029] Step S3: preparing a hydrophobic film layer, cutting it into the main shape of the sweat sensor patch by laser, and then adhering it to the upper surface of the flow channel layer using the adhesive, adhesive or double-sided tape on the upper surface of the flow channel layer. The hydrophobic film layer is also cut along the shape of the plurality of electrode contacts by laser to form the electrode vias;

[0030] Step S4: preparing a double-sided adhesive layer, cutting the double-sided adhesive layer along the shape of the detection module using a laser, further cutting the electrode vias along the electrode contacts, and adhering the double-sided adhesive layer to the upper surface of the hydrophobic film layer;

[0031] Step S5: preparing a bottom layer, cutting the hypoallergenic skin adhesive into the main body shape by laser cutting to form a skin adhesive layer, further cutting a cavity through hole for sweat storage in the skin adhesive layer, attaching the skin adhesive layer to the lower surface of the electrode layer, and attaching a release film to the lower surface of the skin adhesive layer;

[0032] Step S6: Connecting the detection module and the electrode layer, electrically connecting the detection module and the electrode layer through a plug-in interface or a pin-type elastic interface, and adhering the detection module to the upper surface of the hydrophobic film layer through the double-sided adhesive layer.

[0033] The beneficial effects of the present invention are:

[0034] 1. The flexible wearable sweat sensor device provided by the present invention detects sweat volume and electrolyte concentration in a sweat channel of a certain length by providing a sweat channel. The device has a simple manufacturing process, and only requires simple bonding to complete the production of a sensor patch.

[0035] 2. The flexible wearable sweat sensor device provided by the present invention is based on the principle of conductivity. Therefore, the sensor can achieve real-time and continuous detection of sweat volume and sweat electrolyte concentration through the conductivity curve. At the same time, after the sweat is discharged from the flow channel, the sensor can be reused and is not a disposable consumable.

[0036] 3. The present invention designs dual channels to detect the electrolyte concentration and sweat volume in sweat respectively. One sensor can detect two variables at the same time, realizing dual-channel detection, thereby making the detection results more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is an exploded view of the structure of the present invention;

[0038] FIG2 is a structural diagram of the electrode layer in FIG1 ;

[0039] FIG3 is a structural diagram of the flow channel layer in FIG1 ;

[0040] FIG4 is a schematic diagram of an electrical connection method between the detection module and the sweat sensor patch of the present invention;

[0041] FIG4 is a schematic diagram of another electrical connection method between the detection module and the sweat sensor patch of the present invention;

[0042] FIG6 shows the relationship between the change of conductivity over time at different sweat flow rates and an electrolyte concentration of 100 mM in Example 1;

[0043] FIG7 shows the relationship between the change of conductivity over time at different sweat flow rates and an electrolyte concentration of 100 mM in Example 2;

[0044] FIG8 shows the relationship between conductivity and time at different sweat flow rates at an electrolyte concentration of 100 mM in Example 3;

[0045] FIG9 is a schematic diagram of the sweat sensor device of the present invention attached to the surface of human skin;

[0046] in:

[0047] 1. Detection module, 2. Hydrophobic film layer, 3. Flow channel layer, 4. Electrode layer, 5. Bottom layer, 6. Release film layer, 11. Double-sided adhesive layer;

[0048] 101. Spring needle;

[0049] 301, flow channel, 302, flow channel inlet, 303, flow channel outlet, 3011, fillet, 304, electrode via;

[0050] 401, flexible substrate, 4011, liquid inlet, 402, detection interdigital electrode, 4021, first interdigital electrode, 4022, second interdigital electrode, 403, electrode contact;

[0051] 501, sweat storage chamber;

[0052] 701, male end, 702, female end. DETAILED DESCRIPTION

[0053] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] As shown in Figures 1-5, the present invention provides a flexible, wearable, dual-channel sweat sensor device comprising a detection module 1 and a sweat sensor patch. The sweat sensor patch is flexible, while the detection module 1 is rigid. The detection module is electrically connected to the sweat sensor patch via pluggable terminals or spring pins. The detection module collects the conductivity signal from the sweat sensor patch and converts it into information such as electrolyte concentration and sweat volume or sweat rate.

[0056] The detection module integrates a DAC reference voltage generation unit, a voltage conversion unit, an AFE small signal acquisition unit, and a wireless communication unit. The sweat sensor device of the present invention wirelessly transmits signals via the wireless communication unit, communicates with the circuit processing module via the wireless communication module, and transmits the electrical output signal to the circuit processing module. The signal processing circuit in the circuit processing module then processes the received electrical output signal (analog signal) through shaping, amplification, filtering, and A / D conversion to obtain the sensor's output electrical signal (digital signal). The algorithm integrated in the circuit processing module then converts the output electrical signal into a digital sweat monitoring parameter.

[0057] As shown in FIG1 , the detection module 1 is adhered to the upper surface of the sweat sensor patch by means of double-sided tape 11 .

[0058] Furthermore, the size of the detection module is smaller than or equal to the overall size of the sweat sensor patch.

[0059] As shown in FIG1 , the sweat sensor patch includes a hydrophobic membrane layer 2 , a flow channel layer 3 , an electrode layer 4 and a bottom layer 5 that are regularly arranged from top to bottom.

[0060] The bottom layer 5 is a skin adhesive layer for adhering to human skin. The bottom layer 5 is provided with regular openings and forms a sweat receiving chamber 501 between the bottom layer 5 and the electrode layer base.

[0061] Furthermore, a release film layer 6 for protection is attached to the lower surface of the bottom layer 5 .

[0062] During use, the release film layer 6 is removed and the bottom layer 5 is attached to the surface of human skin, thereby attaching the sweat sensor device of the present invention to the surface of human skin. During exercise, the surface of the human skin continuously produces sweat, which enters the sweat receiving chamber 501 between the bottom layer 5 and the electrode layer base.

[0063] Preferably, the bottom layer 5 is made of a hypoallergenic skin film to avoid or reduce allergic reactions to human skin as much as possible.

[0064] Figure 2 shows the structure of electrode layer 4. Electrode layer 4 comprises a flexible substrate 401 and a plurality of interdigital detection electrodes 402 disposed on the upper surface of the flexible substrate. Flexible substrate 401 is provided with a liquid inlet 4011, preferably located in the middle of the substrate and communicating with sweat-receiving chamber 501. The interdigital detection electrodes are regularly arranged in front of liquid inlet 4011.

[0065] Furthermore, the plurality of detection interdigital electrodes 402 include a first interdigital electrode for electrolyte concentration testing / detection and a second interdigital electrode for sweat volume or sweat rate testing / detection. The second interdigital electrode is S-shaped or serpentine-shaped and is regularly arranged in front of the first interdigital electrode.

[0066] Furthermore, the S-shaped second interdigital electrodes cover the entire upper surface of the flexible substrate 401 as much as possible, thereby utilizing the area of ​​the upper surface of the flexible substrate 401 as much as possible. As shown in Figure 2, in one embodiment, the S-shaped second interdigital electrodes are regularly arranged along the left and right sides of the liquid inlet, and the finger electrodes of the second interdigital electrodes on the left and right sides are equidistant and of equal length on the left and right sides of the liquid inlet. Therefore, on a flexible substrate of the same area, longer second interdigital electrodes and flow channels can be arranged. In other words, with second interdigital electrodes and flow channels of the same length, the sweat sensor patch of the present invention can be made smaller.

[0067] Furthermore, a plurality of electrode contacts 403 are regularly arranged on the flexible substrate 401, and a plurality of detection interdigital electrodes 402 are regularly electrically connected to corresponding electrode contacts 403 via leads. In one embodiment, there are six electrode contacts, and the first interdigital electrode and the second interdigital electrode are respectively connected to four of the electrode contacts via leads to form detection electrode contacts. The remaining two electrode contacts serve as power supply electrode contacts.

[0068] Furthermore, the flexible substrate uses a thin film electrode, the thin film material of which 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.

[0069] Figure 3 shows the structure of the flow channel layer 3. Flow channels 301 are regularly arranged on the flow channel layer 3. The front and rear ends of the flow channels 301 are respectively provided with a flow channel inlet 302 for the inflow of sweat and a flow channel outlet 303 for the outflow of sweat. The flow channel inlet 302 is located directly above and connected to the liquid inlet, while the flow channel outlet 303 is located on the side of the flow channel layer 3, thereby leading the flow channel out of the flow channel layer.

[0070] Furthermore, the flow channel inlet 302 on the flow channel layer 3, the liquid inlet 4011 on the electrode layer 4 and the sweat receiving chamber 501 on the bottom layer 5 are vertically arranged and interconnected, so that the sweat secreted by the human body is first stored in the sweat receiving chamber 501, and then flows into the flow channel 301 in the flow channel layer from the liquid inlet 4011 on the electrode layer.

[0071] Furthermore, the flow channel 301 is arranged along the shape of the second interdigital electrode 4022 and directly above it, thereby directing sweat along the plurality of finger-shaped electrodes of the second interdigital electrode, thereby generating a corresponding conductivity signal and achieving sweat measurement. Therefore, in one embodiment, the flow channel 301 is arranged along the S-shaped second interdigital electrode, forming an S-shaped flow channel of equal length and distance on both sides of the flow channel inlet.

[0072] Furthermore, the plurality of finger-shaped electrodes of the first interdigitated electrode and the second interdigitated electrode are all disposed in the flow channel 301 .

[0073] Furthermore, the flow channel 301 is designed to have a rounded corner 3011 at the bend, and the base of the entire flow channel layer is made of hydrophobic material, thereby forming a hydrophobic flow channel to reduce the flow resistance of sweat in the flow channel.

[0074] As shown in FIG1 , the hydrophobic membrane layer 2 covers the upper surface of the flow channel layer 3 , thereby covering and sealing the flow channels in the flow channel layer 3 , ensuring that sweat liquid can flow along the flow channels in the flow channel layer 3 .

[0075] Furthermore, the hydrophobic membrane is laser-cut into its main shape. Six through-holes are laser-cut on its surface to facilitate connection between the electrodes and the outside world. The through-holes have a diameter of 1.4 mm, and the distance between the six through-holes matches that of the electrode layer. The hydrophobic membrane can be made from materials such as polyethylene terephthalate (PET) and ethylene vinyl acetate (EVA).

[0076] As shown in FIG4 and FIG5 , the present invention provides two ways of electrically connecting the detection module to the electrode contacts on the surface of the electrode layer:

[0077] The first method, shown in Figure 4, uses plug-in terminals to achieve electrical connection between the detection module and the electrode layer. Several electrode contacts 403 on the electrode layer 4 are connected via wires, which are then regularly connected via terminals to form a plug terminal (male terminal 701). Accordingly, the detection module is provided with a protruding plug-in connector (female terminal 702). The plug terminal extending from the electrode layer is inserted into the plug-in connector extending from the detection module, thereby achieving electrical connection between the detection module and the electrode layer, and thus, between the detection module and the sweat sensor patch. The detection module is then affixed to a designated location on the upper surface of the sweat sensor patch using a double-sided adhesive layer 11.

[0078] Of course, the male end and the female end can also be arranged in reverse.

[0079] Furthermore, the plug-in interface can also be integrated into the detection module and arranged on the front, back, left, and right sides or on the top of the detection module.

[0080] Furthermore, the wires leading out of the electrode layer pass through the flow channel layer and the hydrophobic film layer respectively. Therefore, electrode vias 304 are regularly arranged on the flow channel layer and the hydrophobic film layer just above the plurality of electrode contacts.

[0081] The second method, shown in Figure 5, uses a top-pin spring interface to achieve electrical connection between the detection module and the electrode contacts on the surface of the electrode layer. A number of spring pins 101 for electrical connection are regularly arranged along the electrode contacts on the detection module 1 and extend from the bottom surface of the detection module. Electrode vias 304 are regularly arranged along the electrode contacts on the hydrophobic membrane layer 2 and the flow channel layer 3. The spring pins 101 pass through the electrode vias in the hydrophobic membrane layer and the flow channel layer to electrically connect with the electrode contacts on the surface of the electrode layer.

[0082] Furthermore, the detection module 1 is adhered to the upper surface of the hydrophobic membrane layer 2 through the double-sided adhesive layer 11 .

[0083] In order to improve the reliability of the detection module and the sweat sensor patch, the double-sided adhesive layer is spread over the lower surface of the detection module as much as possible. Therefore, in one embodiment, the double-sided adhesive layer 11 is also regularly provided with electrode vias for the spring needle to pass through.

[0084] The electrode vias 304 may be through holes having the same number as the electrode contacts 403 , or strip holes avoiding the electrode contact area.

[0085] The present invention also provides a method for preparing a flexible wearable dual-channel sweat sensor device, comprising the following steps:

[0086] Step S1: Prepare an electrode layer 4 by etching copper (nickel gold) electrodes onto a polyimide film. The electrode layer has a thickness of 12-100 μm. A circular through-hole with a diameter of 1 mm is cut into the electrode layer using a laser to form a sweat inlet. Multiple circular electrode contacts, preferably six, are also prepared on the electrode layer. These contacts have a diameter of 0.12-2 mm, preferably 0.9 mm, and the distance between each circle is 0.5-5 mm, preferably 2.5 mm.

[0087] Step S2: Prepare the flow channel layer 3, laser-cut it into the desired flow channel shape, and then attach it to the upper surface of the electrode layer 4. A 1mm diameter through-hole (flow channel inlet) is designed at the entrance of the flow channel layer as a sweat inlet. The flow channel layer can be made of double-sided adhesive film materials such as polyethylene, biaxially oriented polypropylene, and polytetrafluoroethylene, with a thickness of 50-500µm. A hydrophobic material is placed in the center of the flow channel to reduce the flow resistance of sweat in the channel.

[0088] Step S3: Prepare a hydrophobic film layer 2, cut it into a main shape by laser, and then attach it to the upper surface of the flow channel layer 2. At the same time, 6 through holes need to be laser cut on the surface to facilitate the connection of the electrode contacts with the outside world. The diameter of the through hole is 1.4 mm, and the distance between the 6 through holes is consistent with that on the electrode layer. The material of the hydrophobic film can be selected from polyethylene terephthalate (PET), ethylene-vinyl acetate copolymer (EVA) and other materials. The hydrophobic film layer mainly encapsulates the flow channel layer, covering the flow channel layer to ensure that the liquid can flow along the flow channel.

[0089] Step S4: Prepare a double-sided adhesive layer 11. Use 3M VHB strong double-sided adhesive. Laser cut it into a 3*3 cm square structure. Six through-holes are laser cut on the surface to facilitate the connection of the circular electrode contacts on the surface of the electrode layer to the outside world. Then attach it to the upper surface of the hydrophobic film layer 2. The double-sided adhesive ensures that the detection module 1 is tightly connected to the hydrophobic film layer 2 to ensure that it will not fall off during wear.

[0090] Step S5: Connect the detection module 1 and the electrode layer 4 by means of a plug-in interface or a pin-type elastic interface. Attach the detection module 1 to the upper surface of the hydrophobic membrane layer 2 using the double-sided adhesive layer 11.

[0091] Step S6: Prepare the bottom layer 5. First, use laser cutting to cut the hypoallergenic skin adhesive into the main body shape and a 6mm diameter through-hole for the sweat storage chamber, which also serves as the sweat inlet. The bottom layer 5 is then attached to the lower surface of the electrode layer 4. A release film is also attached to the lower surface of the skin adhesive layer. When in use, simply remove the release film and apply it to the human skin surface.

[0092] Furthermore, in one embodiment, the overall length and width of the sweat sensor patch (including the bottom layer, electrode layer, flow channel layer, and hydrophobic membrane layer) are greater than or equal to 6 cm × 3 cm, the size of the detection module is less than or equal to the overall size of the sweat sensor patch, the sweat sensor patch is a flexible structure, and the detection module is a rigid structure. The sweat storage chamber has a diameter of 6-10 mm and a height of 100-200 μm. The sweat storage chamber is a chamber formed by a layer of hypoallergenic skin adhesive vias and the electrode bottom layer. The diameter of the sweat inlet on the electrode layer is 0.3 mm to 10 mm, and the diameter of the sweat inlet on the flow channel layer is comparable to that of the electrode layer, ranging from 0.3 mm to 10 mm. The entire sweat flow channel is designed with rounded corners at the bends, and the inner wall is a hydrophobic flow channel with a width of 0.5 to 4 mm and a thickness of 0.1 to 0.6 mm. Among them, when the width is 1-2mm and the thickness is 0.15-0.3mm, it can better ensure the circulation of sweat, and at the same time, a sweat patch can meet the requirements of one hour of liquid filling time, which is suitable for outdoor sports detection mode. The flow channel also includes a sweat drainage outlet, which is located at the exit of the sweat circulation channel, that is, the edge of the sweat sensor patch for drainage.

[0093] Example 1:

[0094] As shown in FIG1 and FIG5 , this embodiment provides a wearable sweat sensor device for real-time and continuous detection of electrolyte concentration, comprising: a bottom layer and an electrode layer, a silicone rubber flow channel layer, a hydrophobic membrane layer, and a detection module sequentially arranged on the base layer.

[0095] A first sweat inlet is provided on the bottom layer 5, with one end opening positioned close to the skin surface for continuous input of sweat generated on the skin surface. A second sweat inlet is provided on the surface of the electrode layer 4. The first and second sweat inlets allow sweat to reach the surface of the electrode layer and then enter the flow channel layer 3.

[0096] The bottom layer connects the skin and the electrode layer, and the bottom layer provides a sweat receiving chamber 501. The electrode layer is used to detect the amount of sweat flowing through the sweat channel and / or detect the electrolyte concentration by analyzing electrical signals.

[0097] The bottom layer is provided with a hypoallergenic skin adhesive film and a release film 6. When in use, the release film needs to be removed before being applied to the skin surface.

[0098] The material used for the flow channel layer 3 is silicone rubber, and a sweat flow channel is arranged on its surface. The third sweat inlet of the sweat flow channel is vertically connected to the first sweat inlet and the second sweat inlet. The surfaces of the electrolyte concentration detection interdigital electrodes and the sweat amount detection interdigital electrodes of the electrode layer are located on the bottom surface of the sweat flow channel layer, and are used to detect sweat flowing through the sweat channel to obtain electrolyte concentration and sweat amount information in the sweat.

[0099] The flow channel layer is provided with a sweat outlet for conducting the input sweat out of the flow channel layer.

[0100] A hydrophobic membrane layer is provided above the flow channel layer to seal the liquid in the flow channel to prevent overflow during use.

[0101] The sweat sensor patch consists of a bottom layer, electrode layer, flow channel layer, and hydrophobic membrane layer. The overall length and width of the sweat sensor patch are greater than or equal to 6cm*3cm, and the detection module is less than or equal to the overall dimensions of the sweat sensor patch. The sweat sensor patch is a flexible structure, while the detection module is a rigid structure. The sweat storage chamber has a diameter of 6-10mm and a height of 100-200μm. The sweat storage chamber is formed by a layer of hypoallergenic skin adhesive with a via and the bottom electrode layer. The sweat inlet on the electrode layer has a diameter of 0.3mm to 10mm. The sweat inlet on the flow channel layer has a diameter comparable to that of the electrode layer, ranging from 0.3mm to 10mm. The entire sweat channel is designed with rounded corners at bends and a hydrophobic inner wall. Its width ranges from 0.5 to 4 mm and its thickness from 0.1 to 0.6 mm. A width of 1 to 2 mm and a thickness of 0.15 to 0.3 mm ensures better sweat flow and allows a single sweat patch to maintain a full hour of fluid retention, meeting the detection requirements of outdoor sports. The channel also includes a sweat drainage outlet, located at the exit of the sweat channel, i.e., at the edge of the sweat sensor patch.

[0102] During use, the wearable sweat sensor device of this embodiment is attached to the skin epidermis, as shown in Figure 9. When sweat is secreted from the sweat glands, it exerts a certain pressure, reaching a maximum of 70,000 Nm², sufficient to pump the sweat into the first sweat inlet of the bottom layer. As sweat passes through the first sweat inlet and flows upward, it successively contacts the interdigitated electrodes exposed on the surface of the electrode layer. These electrodes are then connected to the detection module via a plug-in or pin-type connection to obtain a real-time conductivity signal from the wearable sweat sensor device. A conductivity detection instrument records the continuous conductivity of the sweat in real time. The conductivity curve is positively correlated with the real-time total electrolyte concentration in sweat and the amount of sweat produced. The time interval between the step changes in the conductivity curve is directly proportional to the sweating rate, and the conductivity signal measured by the first interdigitated electrodes is positively correlated with the real-time electrolyte concentration.

[0103] Therefore, a real-time, continuous conductivity curve can be used to obtain real-time and continuous changes in sweat electrolyte concentration and sweat volume. Figure 6 shows some test results when the flow channel layer is silicone rubber. The upper curve is 4 μl / min, and the lower curve is 3 μl / min.

[0104] Example 2:

[0105] The specific structure of this embodiment refers to that of embodiment 1, wherein the material of the flow channel layer is a biaxially oriented polypropylene film.

[0106] When the flow channel layer is a biaxially oriented polypropylene film, some test results are shown in Figure 7. The upper curve is 4 μl / min and the lower curve is 3 μl / min.

[0107] Example 3:

[0108] The specific structure of this embodiment refers to that of embodiment 1, wherein the material of the flow channel layer is polytetrafluoroethylene film.

[0109] When the flow channel layer is a biaxially oriented polypropylene film, some test results are shown in Figure 8, where the upper curve is 4 μl / min and the lower curve is 3 μl / min.

[0110] The horizontal axis in Figures 6-8 is the time axis, and the vertical axis is the conductivity axis. The coordinates in Figures 6-8 represent the relationship between the change of conductivity over time at different sweat flow rates at an electrolyte concentration of 100 mM.

[0111] For different materials selected for the flow channel layer, the material inside the flow channel and the cutting accuracy on the inside bring different resistance to the liquid. The resistance of silicone material is relatively large, so the time of a single step signal is relatively long. Biaxially oriented polypropylene film is second, and polytetrafluoroethylene is better, with high step signal consistency.

[0112] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are 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 scope of protection of the present invention.

Claims

1. A flexible wearable dual-channel sweat sensing device, characterized by: include: A detection module and a sweat sensor patch, wherein the detection module is electrically connected to the sweat sensor patch via a plug-in interface or a thimble-type spring pin to collect a conductivity signal from the sweat sensor patch and convert the conductivity signal into electrolyte concentration information and sweat volume information / sweating rate information; The detection module internally integrates a reference voltage generation unit, a voltage conversion unit, an AFE small signal acquisition unit and a wireless communication unit; The sweat sensor patch includes a hydrophobic membrane layer, a flow channel layer, an electrode layer and a bottom layer regularly arranged from top to bottom; The bottom layer includes a skin adhesive layer for adhering to human skin and is arranged on the lower surface of the flexible substrate of the electrode layer. Regular openings are arranged on the bottom layer, and a sweat receiving chamber is formed between the bottom layer and the flexible substrate of the electrode layer; The electrode layer includes the flexible substrate and a plurality of detection interdigital electrodes for testing regularly arranged on the upper surface of the flexible substrate, a liquid inlet is provided on the flexible substrate, the plurality of interdigital electrodes are regularly arranged in front of the liquid inlet, and are regularly connected to a plurality of electrode contacts through leads provided on the flexible substrate to form detection electrode contacts; The flow channel layer is regularly provided with flow channels, which are regularly arranged along the shapes of the plurality of detection interdigital electrodes and are arranged directly above the plurality of finger-shaped electrodes between the plurality of detection interdigital electrodes, so as to place the plurality of finger-shaped electrodes between the plurality of detection interdigital electrodes in the flow channel; the front end and the end of the flow channel are respectively provided with a flow channel inlet for sweat to flow in and a flow channel outlet for sweat to flow out, the flow channel inlet being connected to the sweat receiving chamber through the liquid inlet, and the flow channel outlet leading out of the flow channel layer and communicating with the outside world; The hydrophobic film layer is attached to the upper surface of the flow channel layer to encapsulate the flow channels in the flow channel layer.

2. The flexible wearable dual-channel sweat sensor device according to claim 1, characterized in that: The base of the flow channel layer is made of a hydrophobic material, and the bends of the flow channel are rounded to form a hydrophobic flow channel.

3. The flexible wearable dual-channel sweat sensor device according to claim 1, characterized in that: The plurality of detection interdigital electrodes include a first interdigital electrode for electrolyte concentration testing and a second interdigital electrode for sweat volume / sweating rate testing, wherein the first interdigital electrode and the second interdigital electrode are regularly arranged in front of the liquid inlet; The second interdigital electrodes are designed in an S-shape and cover the flexible substrate as much as possible. The second interdigital electrodes are regularly arranged along the left and right sides of the liquid inlet.

4. The flexible wearable dual-channel sweat sensing device according to claim 3, characterized in that: The second interdigitated electrodes on the left and right sides of the liquid inlet are arranged with equal distances and lengths on both sides of the liquid inlet to cover both sides of the flexible substrate as much as possible.

5. A flexible wearable dual-channel sweat sensor device according to any one of claims 1 to 4, characterized in that: Electrode vias are regularly arranged on the flow channel layer and the hydrophobic membrane layer just above the plurality of electrode contacts, for facilitating electrical connection between the detection module and the electrode layer.

6. The flexible wearable dual-channel sweat sensor device according to claim 5, characterized in that: The detection module is adhered to the upper surface of the hydrophobic film layer through a double-sided adhesive layer.

7. The flexible wearable dual-channel sweat sensing device according to claim 6, characterized in that: Electrode vias are also regularly arranged on the double-sided adhesive layer just above the plurality of electrode contacts.

8. The flexible wearable dual-channel sweat sensor device according to claim 1, characterized in that: The sweat sensor patch is a flexible structure, and the detection module is a rigid structure.

9. The flexible wearable dual-channel sweat sensor device according to claim 1, characterized in that: The flexible substrate of the electrode layer is a thin film electrode, and the plurality of detection interdigital electrodes are conductive electrodes.

10. A method for preparing a flexible wearable dual-channel sweat sensor device, characterized in that: The following steps are involved: Step S1: preparing an electrode layer by etching copper or nickel-gold on a flexible substrate to obtain a plurality of detection interdigital electrodes, a plurality of electrode contacts, and electrode leads regularly connecting the plurality of detection interdigital electrodes and the plurality of electrode contacts, and cutting a liquid inlet on the electrode layer using a laser; Step S2: preparing a flow channel layer, cutting the flow channel shape along the shape of the plurality of detection interdigital electrodes by laser, cutting the electrode vias along the shape of the plurality of electrode contacts, designing a flow channel inlet at the front end of the flow channel that is connected to the liquid inlet, and leading the outlet at the end of the flow channel out of the flow channel layer, setting rounded corners at the bends of the flow channel, and adhering the upper and lower surfaces of the flow channel to the upper surface of the electrode layer with adhesive, or adhering to the upper surface of the electrode layer with double-sided tape; Step S3: preparing a hydrophobic film layer, cutting it into the main shape of the sweat sensor patch by laser, and then adhering it to the upper surface of the flow channel layer using the adhesive, adhesive or double-sided tape on the upper surface of the flow channel layer. The hydrophobic film layer is also cut along the shape of the plurality of electrode contacts by laser to form the electrode vias; Step S4: preparing a double-sided adhesive layer, cutting the double-sided adhesive layer along the shape of the detection module using a laser, further cutting the electrode vias along the electrode contacts, and adhering the double-sided adhesive layer to the upper surface of the hydrophobic film layer; Step S5: preparing a bottom layer, cutting the hypoallergenic skin adhesive into the main body shape by laser cutting to form a skin adhesive layer, further cutting a cavity through hole for sweat storage in the skin adhesive layer, attaching the skin adhesive layer to the lower surface of the electrode layer, and attaching a release film to the lower surface of the skin adhesive layer; Step S6: Connecting the detection module and the electrode layer, electrically connecting the detection module and the electrode layer through a plug-in interface or a pin-type elastic interface, and adhering the detection module to the upper surface of the hydrophobic film layer through the double-sided adhesive layer.

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