Uniform sweating simulation and sweat synchronous detection system

Abstract

The utility model relates to a uniform sweating simulation and sweat synchronous detection system which comprises an artificial microfluid skin layer, a detection device, a bottom layer and an injection pump, the bottom layer is provided with a sweat storage chamber for storing sweat, the injection pump is communicated with the sweat storage chamber in the bottom layer through a pipeline, and the artificial microfluid skin layer is arranged on the bottom layer and seals the sweat storage chamber; the artificial microfluid skin layer comprises one or more hydrophobic membrane layers, and a plurality of liquid outlet holes for sweat to flow out are regularly formed in the hydrophobic membrane layers along the sweat storage cavity area. According to the utility model, the adopted manufacturing process is simple, and the artificial microfluid'skin 'membrane is constructed through laser drilling and electrostatic spinning. According to the device, the influence of pressure difference can be overcome, so that detected sweat is introduced into small holes of the PDMS hydrophobic layer through the nylon 6 nanofiber hydrophilic layer and then flows to the surface along the small holes, and the simulation of uniform and stable sweating of the skin is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of measurement and testing, in particular to a uniform sweating simulation and sweat synchronous detection system. Background Art

[0002] The composition of sweat and its mechanisms have been of interest to researchers since the early 20th century. Over the past few decades, sweat-related research has included testing sweat content such as pH, sodium, lactate, conductivity, alcohol, and sweat rate. While sweat can provide important information, it would be even more beneficial if this data could be provided in real time.

[0003] With the rise of sweat monitoring devices, sweat collection methods and sweat component detection have become particularly important. For sweat collection, traditional methods such as full-body washes or absorbent pads require a large amount of sweat for testing, and the sweat collected in this way cannot be used for testing at a certain outflow rate. On the other hand, the current focus on wearable device research is that researchers have spent a lot of effort to modify traditional sweat collection methods to adapt to smaller dimensions for easy portability, but this sweat collection method is small in size and small in sweat collection, resulting in unrepresentative test results. In terms of component detection, most sensors can only detect a certain component, including but not limited to one of glucose, lactic acid, lactose, etc., due to the singleness of sensitive materials and detection methods, and the detection has limitations.

[0004] Despite extensive device development attempts, no method for testing these devices has been identified. Obviously, human subject testing is the gold standard for validating real-time human sweat monitoring devices. However, using human subjects during the development of a device is time consuming and cannot be characterized due to differences in sweating mechanisms, which vary not only from subject to subject, but also due to differences in sweat collection areas or time in the same subject. There are various forms of in vitro or artificial surrogate testing with other types of body fluids, but notably, there is a lack of a device that can accurately simulate human sweating. It is speculated that the lack of such a sweat simulation device can be traced back to three technical challenges:

[0005] (1) The sweat rate density (1-10ul / min) is much lower than the flow rate density usually produced by commercial porous membranes;

[0006] (2) Commercially available membranes do not provide surface energy, pore density, or texture representative of human skin wetting;

[0007] (3) The membrane suffers from bubble point degranulation, which, at low flow rates, results in a very small proportion of pores dominating the entire fluid flow. Utility Model Content

[0008] The technical problem solved by the utility model is to provide a uniform sweat simulation and sweat synchronous detection system, which can continuously and stably realize the simulation of human sweat rate in a wide range, and has a system standardization test platform for automatically controlling the generation of sweat concentration, which will help accelerate the development of sweat collection, concentration and sweat rate equipment. At the same time, the application integrates a mixed detection device, realizing the "one-step" from sweat simulation to sweat component detection.

[0009] The technical solution adopted by the utility model to solve its technical problems is:

[0010] A uniform sweat simulation and sweat synchronous detection system, comprising an artificial microfluidic skin layer, a detection device, a bottom layer and a syringe pump;

[0011] The bottom layer is provided with a sweat storage chamber for storing sweat, the injection pump is connected to the sweat storage chamber in the bottom layer through a pipeline, and the artificial microfluidic skin layer is provided on the bottom layer and seals the sweat storage chamber;

[0012] The artificial microfluidic skin layer comprises one or more hydrophobic membrane layers, on which a plurality of outlet holes for sweat to flow out are regularly arranged along the sweat storage chamber area, a hydrophilic nanofiber layer is attached to the lower surface of the hydrophobic membrane layer, and a plurality of nanofibers on the hydrophilic nanofiber layer extend into the plurality of outlet holes on the hydrophobic membrane layer;

[0013] The detection device includes a first detection electrode for detecting electrolyte concentration and a second detection electrode for detecting glucose concentration. The first detection electrode and the second detection electrode are regularly arranged on the upper surface of the artificial microfluidic skin and regularly arranged on the upper surface of the area of ​​the plurality of liquid outlet holes.

[0014] Furthermore, the first detection electrode is a conductive detection interdigital electrode, including a plurality of finger-shaped electrodes, so as to detect the electrolyte concentration in sweat by the conductivity method; the second detection electrode adopts an electrocatalytic three-electrode detection electrode, including a working electrode, a counter electrode and a reference electrode, and the upper surface of the working electrode is coated with a glucose oxidase layer for catalysis, so as to detect the glucose concentration in sweat through the second detection electrode.

[0015] Furthermore, the thickness of the hydrophobic membrane layer is 100-500 μm, and the diameters of the plurality of liquid outlet holes thereon are 0.2-1 μm.

[0016] Furthermore, the nanofiber layer is a nanofiber mesh with a thickness of 100-500 μm.

[0017] Furthermore, the diameters of the working electrode and the counter electrode are 5-10 mm, and their resistances are ≤100Ω; and the resistance of the reference electrode is 1-5Ω.

[0018] The beneficial effects of the utility model are:

[0019] The utility model provides a device for simulating uniform sweating of "artificial" skin in vitro, which adopts a simple manufacturing process and constructs an artificial microfluidic "skin" membrane through laser drilling and electrostatic spinning. The device can overcome the influence of pressure difference so that the sweat to be tested is introduced into the small holes of the PDMS hydrophobic layer through the nylon 6 nanofiber hydrophilic layer, and then flows to the surface along the small holes, so as to simulate uniform and stable sweating of the skin, breaking the phenomenon of uneven sweat size pushed out by conventional injection pump thrust. At the same time, the device for simulating uniform sweating of "artificial" skin in vitro prepared by the utility model is used to complete the one-step detection of glucose and electrolyte concentrations in sweat. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the structural principle diagram of the utility model;

[0021] Figure 2 This is a structural diagram of a single-layer artificial microfluidic skin layer of the utility model;

[0022] Figure 3 This is a structural diagram of the multi-layer artificial microfluidic skin layer of the utility model;

[0023] Figure 4 This is a schematic diagram of the multi-layer artificial microfluidic skin layer of the utility model;

[0024] Figure 5 This is a structural diagram of the detection device of the utility model;

[0025] Figure 6 for Figure 5 Preparation process flow chart of the detection device;

[0026] in:

[0027] 1. artificial microfluidic skin layer, 101. hydrophobic membrane layer, 102. nanofiber layer, 1011. liquid outlet;

[0028] 2. Detection device, 201. first detection electrode, 202. second detection electrode, 2021. working electrode, 2022. counter electrode, 2023. reference electrode, 203. wire, 204. electrode contact, 2041. electrolyte concentration detection electrode contact, 2042. glucose detection electrode contact;

[0029] 3. Bottom layer, 301. Sweat storage chamber, 4. Injection pump, 5. Sweat. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] like Figure 1-5 As shown, the utility model provides a uniform sweat simulation and sweat synchronous detection system, including an artificial microfluidic skin layer 1, a detection device 2, a bottom layer 3 and an injection pump 4. The bottom layer 3 is provided with a sweat storage chamber 301 for storing sweat 5, and the injection pump 4 is connected to the sweat storage chamber 301 in the bottom layer through a pipeline, thereby providing power for the output of sweat to simulate the sweating process of the human body. The artificial microfluidic skin layer 1 is arranged on the bottom layer 3 and the sweat storage chamber 301 is sealed, thereby simulating the human epidermis.

[0033] Furthermore, a plurality of outlet holes 1011 for sweat outflow are regularly arranged at the position area of ​​the sweat storage chamber 301 on the artificial microfluidic skin layer 1, and the detection device 2 is regularly arranged on the upper surface of the artificial microfluidic skin and in the area located at the plurality of outlet holes 1011, so as to detect the composition of sweat.

[0034] Further, such as Figure 2 As shown, the artificial microfluidic skin layer 1 is a porous hydrophobic membrane 101, on which a plurality of liquid outlet holes 1011 are regularly arranged. The material of the hydrophobic membrane includes but is not limited to any one of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyimide (PI) or a composite material.

[0035] Further, such as Figure 2 and Figure 5As shown, the detection device 2 includes a first detection electrode 201 and a second detection electrode 202. The first detection electrode 201 adopts a conductive detection interdigital electrode, including a plurality of finger electrodes, so as to test / detect the electrolyte concentration in sweat by the conductivity method. The second detection electrode 202 adopts an electrocatalytic three-electrode detection electrode, including a working electrode 2021, a counter electrode 2022 and a reference electrode 2023. Among them, the upper surface of the working electrode 2021 is coated with glucose oxidase for catalysis, so as to test / detect the glucose concentration in sweat by the second detection electrode.

[0036] Furthermore, the first detection electrode 201 for electrolyte concentration detection and the second detection electrode 202 for glucose concentration detection are led out to the electrode contact 204 through the wire 203, so as to facilitate the subsequent connection of the detection module / circuit.

[0037] like Figure 5 As shown, the first detection electrode 201 is led out to two electrolyte concentration detection electrode contacts 2041 through two wires 203, and the second detection electrode 202 is led out to three glucose concentration detection electrode contacts 2042 through three wires.

[0038] The artificial microfluidic skin layer 1 in the utility model adopts a single-layer or double-layer structure.

[0039] like Figure 2 As shown, when the artificial microfluidic skin layer 1 adopts a single-layer hydrophobic membrane structure with holes, the PDMS membrane is preferably used alone as the artificial microfluidic skin of the utility model. By punching micropores of the same size on the PDMS membrane, a dual-function electrode detection device of a first detection electrode and a second detection electrode is covered on the upper surface of the PDMS membrane.

[0040] Experiments have shown that when the syringe pump injects sweat liquid into the PDMS membrane at a flow rate of 10 μL / min, the liquid will flow out from most of the holes. Since the size of the holes cannot be guaranteed to be completely uniform, some large holes cannot overcome the pressure drop in the Young-Laplace equation.

[0041] Young-Laplace equation: ΔP = 4γcos(θ) / D;

[0042] Among them, γ is the surface tension of the liquid, which is related to the temperature, pressure and interfacial properties of the material and is a constant under the experimental conditions; θ is the contact angle of the liquid in the hole, which is related to the material nature and surface tension and is a constant under the experimental conditions; D is the diameter of the hole.

[0043] When the flow rate is reduced, the water injection driving force F will become smaller, and the relatively larger pores will be subjected to a larger pressure difference, so most of the liquid will flow out from a single hole or small holes. Although the effect of skin sweating can be simulated in this embodiment, it is impossible to simulate the skin to achieve uniform sweating.

[0044] Therefore, further, Figure 3 and Figure 4 As shown, in the simulated artificial skin in vitro uniform sweating and mixing detection device of the present invention, the artificial microfluidic skin layer 1 adopts a double-layer structure, including a hydrophobic film layer 101 with holes and a hydrophilic nanofiber layer 102. Among them, the hydrophobic film layer 101 with holes is attached to the upper surface of the hydrophilic nanofiber layer 102. In this way, because the apertures of the several liquid outlet holes on the hydrophobic film layer 101 are much larger than the diameters of the nanofibers on the nanofiber layer, when the hydrophobic film layer with holes is attached to the hydrophilic nanofiber layer, the several nanofibers on the nanofiber layer will extend into the several liquid outlet holes 1011 on the hydrophobic film layer.

[0045] The hydrophilic nanofibers 102 are used as a hydrophilic layer and are arranged on the bottom surface of the hydrophobic membrane layer 101 with holes. Due to the hydrophilic effect, the sweat liquid will enter the nanofibers, pass through the nanofibers embedded in the liquid outlet holes, and then enter the several liquid outlet holes on the hydrophobic membrane layer, and then overcome the pressure difference in the Young-Laplace equation to directly discharge the sweat, thereby better simulating the sweating effect of human skin.

[0046] The hydrophobic material of the hydrophobic membrane layer 101 includes but is not limited to any one or more composite materials of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), and polyimide (PI). The PDMS membrane is preferably selected to have a thickness of 100-500 μm, and a plurality of liquid outlet holes with an aperture of 0.2-1 μm are regularly cut by laser.

[0047] The hydrophilic material of the hydrophilic nanofiber layer 102 includes, but is not limited to, any one or more composite materials of nylon 6 nanofiber and nylon 66 nanofiber. Nylon 6 nanofiber is preferably used, and a nanofiber network of a certain thickness is obtained on a substrate by electrospinning technology, and the thickness is 100-500 μm. The shape of the constructed network can be square, circular, polygonal, etc., and the side length or diameter is greater than or equal to 2 cm.

[0048] Furthermore, the PDMS membrane and the nanofiber membrane are tightly combined by pressing, and then a dual-function detection electrode device for detection is attached to the surface of the PDMS.

[0049] like Figure 3 and Figure 5As shown, the detection device 2 is a dual-function detection electrode, including a first detection electrode 201 for detecting electrolyte concentration and a second detection electrode 202 for detecting glucose concentration. The utility model prepares the dual-function detection electrode by using a screen printing process on a flexible substrate.

[0050] The detection principle of the utility model is as follows:

[0051] The detection principles for glucose and electrolytes are not the same. First, the detection principle of glucose is to use glucose oxidase (GOx) to catalyze the oxidation of glucose into gluconolactone under the application of a certain voltage and generate a corresponding oxidation peak current, thereby obtaining a glucose concentration curve.

[0052] The electrolyte concentration is tested through the conductivity method. When the liquid passes through the electrodes, a path is formed in the interdigitated electrodes, thereby obtaining a conductivity signal. Different electrolyte concentrations are then corresponding to different conductivity values.

[0053] 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 uniform sweating simulation and sweat synchronous detection system, characterized in that: It includes an artificial microfluidic skin layer, a detection device, a bottom layer and a syringe pump; The bottom layer is provided with a sweat storage chamber for storing sweat, the injection pump is connected to the sweat storage chamber in the bottom layer through a pipeline, and the artificial microfluidic skin layer is provided on the bottom layer and seals the sweat storage chamber; The artificial microfluidic skin layer comprises one or more hydrophobic membrane layers, on which a plurality of outlet holes for sweat to flow out are regularly arranged along the sweat storage chamber area, a hydrophilic nanofiber layer is attached to the lower surface of the hydrophobic membrane layer, and a plurality of nanofibers on the hydrophilic nanofiber layer extend into the plurality of outlet holes on the hydrophobic membrane layer; The detection device includes a first detection electrode for detecting electrolyte concentration and a second detection electrode for detecting glucose concentration. The first detection electrode and the second detection electrode are regularly arranged on the upper surface of the artificial microfluidic skin and regularly arranged on the upper surface of the area of ​​the plurality of liquid outlet holes.

2. A uniform sweating simulation and sweat synchronous detection system as claimed in claim 1, characterized in that: The first detection electrode is a conductive detection interdigital electrode, including a plurality of finger-shaped electrodes, so as to detect the electrolyte concentration in sweat by the conductivity method; the second detection electrode adopts an electrocatalytic three-electrode detection electrode, including a working electrode, a counter electrode and a reference electrode, and the upper surface of the working electrode is coated with a glucose oxidase layer for catalysis, so as to detect the glucose concentration in sweat through the second detection electrode.

3. A uniform sweat simulation and sweat synchronous detection system as claimed in claim 2, characterized in that: The thickness of the hydrophobic membrane layer is 100-500 μm, and the diameters of the plurality of liquid outlet holes thereon are 0.2-1 μm.

4. A uniform sweat simulation and sweat synchronous detection system as claimed in claim 3, characterized in that: The nanofiber layer adopts a nanofiber mesh with a thickness of 100-500 μm.

5. A uniform sweat simulation and sweat synchronous detection system as claimed in any one of claims 2 to 4, characterized in that: The diameters of the working electrode and the counter electrode are 5-10 mm, and their resistances are ≤100Ω; the resistance of the reference electrode is 1-5Ω.

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