A wearable sweat sensor and a method for sweat detection

Abstract

This application discloses a wearable sweat sensor and a sweat detection method. The wearable sweat sensor includes a sweat collection layer, a channel layer, a sweat guiding layer, a detection layer, and a sensor layer; the detection layer includes a detection pool and a water storage pool; the detection pool and the water storage pool are connected by a capillary breakthrough valve; the capillary breakthrough valve allows liquid to enter the detection pool from the water storage pool in only one direction; the sensor layer has an external interface; the external interface is connected to the water storage pool.

Description

Technical Field

[0001] This application relates to a wearable sweat sensor and a sweat detection method, belonging to the field of wearable sensors. Background Technology

[0002] Sweat contains electrolytes (K) + Na + Sweat contains substances such as Cl-, metabolites (glucose, uric acid, etc.), and nutrients (tyrosine, tryptophan, etc.). These substances can reflect the health status of the human body. For example, the concentration of glucose in sweat is positively correlated with the concentration of glucose in blood, and sweat glucose is 1-2% of blood glucose concentration (European Journal of Clinical Nutrition, 2018, 72(1), 69). Therefore, glucose in sweat can serve as indirect evidence of changes in blood glucose concentration; Cl- in sweat... - The concentration can be used as a standard for cystic fibrosis (Nature Biotechnology, 2019, 37, 407-419).

[0003] Currently published wearable sweat sensors all utilize fluid channels to directionally transfer sweat to the surface of the sensing element for detection (Nature Biomedical Engineering, 2022, 6, 1225-1235; Biosensors and Bioelectronics, 2021, 172, 112750). However, sweat is not a good cleaning solution, and after measurement, it cannot be guaranteed that there will be no residual substances on the sensing element surface that could affect detection. This could impact the accuracy and repeatability of long-term monitoring data, potentially leading to a high false alarm rate. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a cleanable microfluidic platform for sweat wearable sensors. Its advantage lies in introducing a cleanable fluid pathway into the sensor. After detection, the surface of the sensing element can be cleaned with an external cleaning solvent, ensuring that no interfering substances remain on the surface of the sensing element during each detection. This provides technical support for the long-term use of sweat wearable sensors.

[0005] According to one aspect of this application, a sweat wearable sensor is provided, the sweat wearable sensor comprising a sweat accumulation layer, a channel layer, a sweat guiding layer, a detection layer and a sensor layer;

[0006] The sweat wearable sensor is obtained by stacking the layers sequentially.

[0007] The detection layer includes a detection pool and a water storage pool;

[0008] The detection pool and the water storage pool are connected by a capillary breakthrough valve.

[0009] The capillary breakthrough valve allows liquid to enter the detection tank only in one direction from the water storage tank.

[0010] The sensor layer is equipped with an external interface;

[0011] The external interface is connected to the water storage tank.

[0012] The divergence angle of the capillary breakthrough valve on the side near the water storage tank is 80-100°;

[0013] The divergence angle of the capillary breakthrough valve on the side near the detection cell is 10–40°.

[0014] The channel layer and the sweat guiding layer are provided with microfluidic channels;

[0015] The diameter of the microfluidic channel is 50–500 μm.

[0016] The diameter of the detection cell is 50 to 1000 times the diameter of the microfluidic channel;

[0017] The diameter of the detection pool is the same as the diameter of the sensing element on the sensor layer.

[0018] The diameter of the reservoir is 200–1000 μm.

[0019] The thickness of any one of the sweat collection layer, channel layer, sweat diversion layer, detection layer, or sensor layer is 0.08–0.15 mm.

[0020] The sweat-guiding layer has sweat outflow channels through which liquid can flow out.

[0021] The distance between the capillary breakthrough valve and the detection tank is matched according to the size of the sensor.

[0022] The capillary breakthrough valve is shaped like an arrow, with the arrow pointing from the water storage tank to the detection tank.

[0023] The channel layer is made of polyester.

[0024] The sweat-wicking layer and the detection layer are made of a hydrophobic adhesive material.

[0025] According to another aspect of this application, a method for detecting sweat using the aforementioned wearable sweat sensor is provided, comprising the following steps:

[0026] Sweat accumulates in the sweat accumulation layer and enters the detection pool on the detection layer through the microfluidic channels on the channel layer and the sweat guiding layer. It then contacts the sensing element on the sensing layer for detection. After the detection is completed, cleaning solution is introduced into the water storage pool on the detection layer through the external interface on the sensing layer and enters the detection pool through the capillary breakthrough valve to clean the detection pool and the surface of the sensing element.

[0027] The beneficial effects that this application can produce include:

[0028] 1. In the method of the present invention, the cleanable microfluidic platform introduces a fluid channel for external cleaning solution to clean the surface of the sensing element without affecting the flow of sweat to the surface of the sensing element, thus ensuring that there are no interfering substances remaining on the surface of the sensing element.

[0029] 2. The cleanable microfluidic platform in the method of this invention provides technical support for long-term monitoring of sweat wearable sensors. Attached Figure Description

[0030] Figure 1 The sweat wearable sensor with a clean flow path is shown in Example 1.

[0031] Among them, 1-sweat collection layer, 2-PET layer, 3-sweat diversion layer, 4-detection layer, 5-sensor layer. a-detection pool, b-capillary breakthrough valve, c-water storage pool, d-external interface. Detailed Implementation

[0032] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0033] Device example 1

[0034] A cleanable microfluidic platform for wearable sweat sensors includes a flow-guiding structure composed of multilayer medical double-sided adhesive and PET, and a sensing layer with sensing elements. Figure 1As shown, layers 1, 3, and 4 are all medical-grade double-sided adhesive, and layer 2 is a PET layer. Layer 1 is the sweat collection layer, adhering closely to the skin surface to collect secreted sweat; layer 2 is the sweat channel; layer 3 is the sweat diversion layer, ensuring that vertically flowing sweat is redirected to lateral flow; layer 4 is the detection pool layer, ensuring full contact between sweat and the surface of the sensing element, and repeatable detection of sweat volume; layer 5 is the sensing layer, detecting the analyte in the sweat. The detection pool a and the reservoir c located in layer 4 are connected by a capillary breakthrough valve b. Detection pool a has a diameter of 30 mm, covering the entire sensing element. Reservoir c has a diameter of 10 mm. Capillary breakthrough valve b ensures that the solution flows directionally from reservoir c into detection pool a, with a width of 0.1 mm and a height of 0.1 mm. The emission angle of capillary breakthrough valve b near detection pool a is 13°, and the emission angle near reservoir c is 90°.

[0035] After the sweat detection is completed, 0.5 mL of cleaning solvent can be introduced into the water tank c through the external interface d. The cleaning solvent flows sequentially through the water tank c, the capillary breakthrough valve b, and the detection tank a, cleaning the detection tank and the surface of the sensing element.

[0036] Example 1

[0037] A cleanable microfluidic platform for a sweat-wearable sensor, as described in Example 1, was used to detect 10 μM glucose.

[0038] Without cleaning the sensor surface, three consecutive measurements were taken, yielding results of 97.3 μA, 80.6 μA, and 65.7 μA, respectively. The RSD of the measurement results was 19.5%.

[0039] The sensor surface was cleaned using an external cleaning flow path, and three consecutive measurements were taken: 99.2 μA, 92.6 μA, and 97.4 μA. The RSD of the measurement results was 3.5%.

[0040] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A wearable sweat sensor, characterized in that, The wearable sweat sensor includes a sweat collection layer, a channel layer, a sweat diversion layer, a detection layer, and a sensor layer. The sweat wearable sensor is obtained by stacking the layers sequentially. The detection layer includes a detection pool and a water storage pool; The detection pool and the water storage pool are connected by a capillary breakthrough valve. The capillary breakthrough valve allows liquid to enter the detection tank only in one direction from the water storage tank. The sensor layer is equipped with an external interface; The external interface is connected to the water storage tank; After the test is completed, the cleaning solution is introduced into the water tank on the detection layer through the external interface on the sensor layer, and then enters the detection pool through the capillary breakthrough valve to clean the detection pool and the surface of the sensing element.

2. The wearable sweat sensor according to claim 1, characterized in that, The divergence angle of the capillary breakthrough valve on the side near the water storage tank is 80~100°.

3. The wearable sweat sensor according to claim 1, characterized in that, The divergence angle of the capillary breakthrough valve on the side near the detection cell is 10~40°.

4. The wearable sweat sensor according to claim 1, characterized in that, The channel layer and the sweat guiding layer are provided with microfluidic channels; The diameter of the microfluidic channel is 50~500 μm.

5. The wearable sweat sensor according to claim 4, characterized in that, The diameter of the detection cell is 50 to 1000 times the diameter of the microfluidic channel.

6. The wearable sweat sensor according to claim 1, characterized in that, The diameter of the detection pool is the same as the diameter of the sensing element on the sensor layer.

7. The wearable sweat sensor according to claim 1, characterized in that, The diameter of the reservoir is 200~1000μm.

8. The wearable sweat sensor according to claim 1, characterized in that, The thickness of each of the sweat accumulation layer, channel layer, sweat diversion layer, detection layer, or sensor layer is independently 0.08~0.15mm.

9. The wearable sweat sensor according to claim 1, characterized in that, The sweat-guiding layer has sweat outflow channels through which liquid can flow out.

10. A method for detecting sweat using a wearable sweat sensor according to any one of claims 1 to 9, characterized in that, Includes the following steps: Sweat accumulates in the sweat accumulation layer and enters the detection pool on the detection layer through the microfluidic channels on the channel layer and the sweat guiding layer, where it comes into contact with the sensing element on the sensor layer for detection.

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