K < + > response type hydrogel strain sensor and rapid and convenient quantitative detection method for trace blood potassium

Abstract

The invention belongs to the field of biomedical sensors and blood potassium detection, and provides a K < + > response type hydrogel strain sensor and a rapid and convenient quantitative detection method for trace blood potassium. The K < + > response type hydrogel strain sensor is composed of a K < + > response type hydrogel layer and a resistance strain gauge, the resistance strain gauge comprises a substrate and a sensitive grid wire, and the substrate is a surface silanization modified synthetic resin substrate; the K < + > response type hydrogel layer is combined on the substrate through chemical bonds and completely covers the sensitive grid wires; a gel polymer network of the K < + > response type hydrogel layer is formed by physical crosslinking of a linear polymer poly (N-isopropylacrylamide-co-4-acrylamide benzene-15-crown-5) and a physical crosslinking agent Laponite XLG nanosheets. Based on the strain sensor, the invention also provides a rapid and convenient quantitative detection method for trace blood potassium. According to the invention, rapid detection of serum K < + > concentration can be realized under the condition of trace serum sample dosage.

Description

Technical Field

[0001] The present invention belongs to the field of biomedical sensors and potassium blood detection, and relates to a K + -responsive hydrogel strain sensor and a rapid, convenient and quantitative detection method for trace potassium blood. Background Art

[0002] Potassium ion (K + ) is the main cation maintaining cell physiological activities and plays a key role in physiological functions such as maintaining electrolyte balance, nerve impulse transmission and muscle contraction. The normal range of human serum K + concentration is 3.5 - 5.5 mmol / L. When the serum K + level is abnormal, whether it is hyperkalemia (serum K + > 5.5 mmol / L) or hypokalemia (serum K + < 3.5 mmol / L), it may cause serious health problems. Hyperkalemia is common in situations such as renal failure and excessive intracellular potassium release, and may cause arrhythmia, reduced myocardial contractility, and even cardiac arrest; while hypokalemia will cause symptoms such as muscle weakness, increased heart rate, and intestinal paralysis.

[0003] Currently, methods for detecting serum K + concentration include spectroscopy, chemical method, electrochemistry method, etc. Spectroscopy methods include flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS) and Raman scattering spectrometry (RSS), which achieve detection by analyzing spectral information of the absorption or scattering characteristics of atoms for light with specific wavelengths, and have high detection sensitivity. However, spectroscopy methods require complex and expensive precision instruments, and at the same time rely on the operation of trained professionals, which is very inconvenient in actual detection, and the detection process is complex and the sample consumption is large. For example, flame atomic absorption spectrometry requires complex sample pretreatment steps and requires more than 2 mL of serum samples. The chemical method is based on the basic principle of specific chemical reactions to achieve detection. For example, serum K + concentration can be detected by the sodium tetraphenylborate method, using the chemical reaction between sodium tetraphenylborate and K + to generate a precipitate, thereby causing a change in the turbidity of the solution, and the concentration of serum K + can be calculated by measuring the change in turbidity. The electrochemistry method uses an ion-selective electrode (ISE) to measure the change in membrane potential generated by a specific chemical reaction between a blood sample and the electrode to determine the K + concentration. Although this method has high sensitivity, its detection accuracy is easily interfered by other ions in the sample, and the requirement for sample pretreatment is high.

[0004] Polymer materials, especially polymer intelligent hydrogels, have attracted the attention of researchers due to their significant stimulus responsiveness, excellent flexibility, and remarkable plasticity. Generally, by incorporating functional groups (such as crown ether 15-crown-5) that can specifically recognize K + , it is possible to detect K + concentration using polymer materials. Currently, there are reports on using linear polymer poly(N-isopropylacrylamide-co-benzo-15-crown-5-acrylamide) to detect serum K + concentration. After recognizing K + under isothermal conditions, the linear polymer changes from a swollen state to a contracted state, resulting in a change in the transmittance of the solution. To quantitatively detect K + concentration in serum, the transmittance of the solution must be accurately measured. However, the transmittance of the solution is always difficult to observe, and its measurement sensitivity is relatively low. Crosslinking the polymer to form a hydrogel, and by measuring the volume contraction of the hydrogel after recognizing K + , the serum K + concentration can be quantitatively detected, which can overcome the deficiencies of linear polymers in K + detection. Currently, the measurement of the hydrogel volume contraction is achieved through the signal conversion of a hydrogel grating sensor. When the intelligent hydrogel contacts K + , the height of the hydrogel grating will change at the nanoscale, which in turn leads to a change in the diffraction efficiency. However, since the hydrogel grating sensor uses diffracted light as the detection signal, in order to ensure accurate detection, the transparency of the hydrogel grating needs to be maintained. However, for the detection of blood samples, the transparency of the hydrogel grating will inevitably be affected by the substances in the blood sample. Therefore, the method using diffracted light as the detection signal is not suitable for the determination of K + concentration in blood samples.

[0005] In addition, considering that the deformation of the hydrogel is crucial for signal transduction, there is a huge demand for hydrogels that can achieve effective stimulus response and strong mechanical properties in practical applications. Existing stimulus-responsive hydrogels are usually prepared by chemical crosslinking (such as using chemical crosslinking agents such as N,N'-methylenebisacrylamide and 4-arm polyethylene glycol acrylamide). Chemical crosslinking agents usually form a stable three-dimensional hydrogel network through covalent bonds generated by free radical polymerization. Hydrogels prepared by chemical crosslinking often exhibit a high crosslinking density, which will increase the spatial barrier for K + transport and limit the mobility of molecular chains, resulting in lower response efficiency and mechanical properties of the hydrogel, which is not conducive to the efficient detection of K + . Generally speaking, developing a method that can quickly and quantitatively detect K + concentration in a small volume of serum samples still faces great challenges at present. Summary of the Invention

[0006] In view of the problem that the method of signal conversion using hydrogel gratings in the prior art is difficult to be applicable to the quantitative detection of K in blood samples, and the problem that the response efficiency and mechanical properties of the existing responsive hydrogels prepared based on chemical cross-linking agents are insufficient, which is not conducive to the efficient detection of K, the present invention provides a K + responsive hydrogel strain sensor and a rapid, convenient and quantitative detection method for trace blood potassium, so as to achieve the rapid detection of serum K + concentration under the condition of using a small amount of serum sample. + Under the condition of using a small amount of serum sample, the present invention provides a K + responsive hydrogel strain sensor and a rapid, convenient and quantitative detection method for trace blood potassium, so as to achieve the rapid detection of serum K

[0007] To achieve the above-mentioned invention purpose, the following technical solution is adopted in the present invention:

[0008] A K + responsive hydrogel strain sensor, which is composed of a K + responsive hydrogel layer and a resistance strain gauge. The resistance strain gauge includes a base, a sensitive grid wire, a covering layer and a lead wire. The base is a synthetic resin base modified by surface silanization; K + responsive hydrogel layer is bonded to the base by chemical bonds and completely covers the sensitive grid wire of the resistance strain gauge; the K + responsive hydrogel layer's gel polymer network is physically cross-linked by linear polymer poly(N-isopropylacrylamide-co-4-acrylamidobenzo-15-crown-5) and physical cross-linking agent Laponite XLG nanosheets.

[0009] In the technical solution of the above K + responsive hydrogel strain sensor, the K + responsive hydrogel layer is composed of K + responsive hydrogel. The content of Laponite XLG nanosheets in the K + responsive hydrogel is preferably 0.01 - 0.05 mol / L.

[0010] Furthermore, in the technical solution of the above K + responsive hydrogel strain sensor, the K +The responsive hydrogel layer is obtained by subjecting a gel prepolymer solution to a photoinitiated polymerization reaction. The gel prepolymer solution is prepared by dispersing a functional monomer 4-acrylamidobenzo-15-crown-5, a gel monomer N-isopropylacrylamide, and a photoinitiator in a Laponite XLG nanosheet dispersion. In the gel prepolymer solution, the molar ratio of benzo-15-crown-5-acrylamide to N-isopropylacrylamide is (0.05 - 0.2):1, and the concentration of the N-isopropylacrylamide monomer is 0.5 - 2 mol / L. Further, the Laponite XLG nanosheet dispersion is prepared by dispersing Laponite XLG nanosheets in water. In the Laponite XLG nanosheet dispersion, the concentration of the Laponite XLG nanosheets is preferably 0.01 - 0.05 mol / L.

[0011] Further, the above K + In the technical solution of the responsive hydrogel strain sensor, the role of the photoinitiator in the gel prepolymer solution is to initiate the copolymerization reaction of the functional monomer 4-acrylamidobenzo-15-crown-5 and the gel monomer N-isopropylacrylamide under the illumination condition of an appropriate wavelength. The type and dosage of the photoinitiator are based on the principle of being able to initiate the copolymerization reaction of the above two monomers and can be selected according to actual application requirements. For example, 2,2-diethoxyacetophenone can be selected as the photoinitiator. Correspondingly, the volume content of the photoinitiator in the gel prepolymer solution is controlled to be 0.1% - 0.5%.

[0012] The above K + In the technical solution of the responsive hydrogel strain sensor, K + The preparation method of the responsive hydrogel strain sensor is as follows: Place the above-mentioned resistive strain gauge in a mold, add the gel prepolymer solution to the mold so that the gel prepolymer solution is located on the substrate side of the resistive strain gauge and contacts the substrate, and photoinitiate the polymerization of the gel prepolymer solution to transform the gel prepolymer solution into a hydrogel state, thus obtaining it. The above K + In the technical solution of the responsive hydrogel strain sensor, the K + The thickness of the responsive hydrogel layer is preferably 0.2 - 1 mm. Regarding K + The main reasons for the thickness of the responsive hydrogel layer being preferably in the range of 0.2 - 1 mm are as follows:

[0013] First, K + The thickness of the responsive hydrogel layer has a great influence on the detection sensitivity and the response value and response range of the responsive hydrogel layer strain sensor. A thinner + responsive hydrogel layer conforms to the curved surface, can withstand repeated mechanical deformations, and improves the strain transfer efficiency from the + responsive hydrogel layer to the resistive strain gauge, thereby improving the + responsive hydrogel layer to the resistive strain gauge, thereby improving the+ The sensitivity of the responsive hydrogel strain sensor to mechanical deformation and K + The overall flexibility of the responsive hydrogel strain sensor. Secondly, in order to improve K + The K of the responsive hydrogel layer + Responsive performance, a thinner K + The responsive hydrogel layer shows a faster response time due to the shortened diffusion path length of K + which is crucial for real-time strain detection that requires fast signal transduction. Thirdly, the thinner K + responsive hydrogel layer can minimize background noise and interference, thus obtaining a higher signal-to-noise ratio in strain detection. This in turn improves the accuracy and reliability of the sensor. However, an overly thin K + responsive hydrogel layer may not provide sufficient mechanical strength and toughness, resulting in unstable signal output and being more vulnerable to external interference. Therefore, through systematic experiments, the present invention finally determines the preferred thickness of the above-mentioned K + responsive hydrogel layer by comprehensively considering the above multiple factors.

[0014] In the above technical solution of the K + responsive hydrogel strain sensor, the resistive strain gauge is preferably a thin-film resistive strain gauge.

[0015] In the above technical solution of the K + responsive hydrogel strain sensor, the used resistive strain gauge is obtained by surface silanization modification of the substrate of the existing commercial resistive strain gauge based on synthetic resin. The method for surface silanization modification of the substrate of the resistive strain gauge can refer to the prior art. More specifically, the surface-silanized modified synthetic resin substrate is obtained by grafting reaction of the synthetic resin substrate with a silane coupling agent containing a carbon-carbon double bond after plasma treatment. The specific grafting reaction conditions can be determined according to the selected silane coupling agent containing a carbon-carbon double bond with reference to the prior art.

[0016] Furthermore, in the above technical solution of the K + responsive hydrogel strain sensor, the silane coupling agent containing a carbon-carbon double bond includes 3-(methacryloyloxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane or γ-methacryloyloxypropyltrimethoxysilane, but the feasible silane coupling agents containing a carbon-carbon double bond are not limited to the specific types listed above.

[0017] Furthermore, in the above technical solution of the K +In the technical solution of the responsive hydrogel strain sensor, the synthetic resin substrate includes a polyimide substrate, a phenolic resin substrate, a phenolic-acetal resin substrate, an epoxy resin substrate, or a polyester resin substrate, but the feasible synthetic resin substrates are not limited to the specific types listed above.

[0018] The present invention also provides a rapid and convenient quantitative detection method for trace potassium in blood, comprising the following steps:

[0019] ① Connect the above-mentioned K + responsive hydrogel strain sensor to a Wheatstone bridge module integrated data acquisition device to form a detection device;

[0020] ② Prepare a series of standard specimens with different K + concentrations. Place the K + responsive hydrogel strain sensor of the detection device on a hot stage. In the order of increasing K + concentration, sequentially and uniformly drop the standard specimens onto the K + responsive hydrogel layer of the K + responsive hydrogel strain sensor. After the microstrain measured by the Wheatstone bridge module integrated data acquisition device reaches stability, record the microstrain corresponding to each standard specimen; obtain a series of microstrains corresponding to the standard specimens;

[0021] Using the microstrain corresponding to each standard specimen as the ordinate and the K + concentration of each standard specimen as the abscissa, plot a working curve to determine the conversion relationship between the K + concentration and the microstrain;

[0022] ③ Replace the K + responsive hydrogel strain sensor used in step ② with the same K + responsive hydrogel strain sensor, or restore the K + responsive hydrogel layer of the K + responsive hydrogel strain sensor used in step ② to the state before the test in step ②;

[0023] Replace the standard specimen in step ② with the test specimen to be tested. Measure the microstrain corresponding to the test specimen to be tested according to the operation in step ②, and calculate the K + concentration of the test specimen to be tested according to the conversion relationship between the K + concentration and the microstrain determined in step ②;

[0024] In steps ② and ③, control the temperature of the standard specimen and the test specimen to be tested to be the same as the temperature of the hot stage, control the temperature of the hot stage to be a constant value between 25 and 40 °C, control the dropping amounts of the standard specimen and the test specimen to be tested to be the same, and the test specimen to be tested is a serum specimen.

[0025] In steps ② and ③ of the technical solution of the above-mentioned rapid and convenient quantitative detection method for trace blood potassium, the dropping amount of the standard sample and the sample to be tested should at least cover the K + responsive hydrogel layer completely.

[0026] The present invention has confirmed through experiments that for a 3AA model standard resistance strain gauge with a size specification of 6.4 mm × 3.5 mm, a K + responsive hydrogel layer with a thickness of 0.3 mm is combined on the resistance strain gauge to form a K + responsive hydrogel strain sensor. When the dropping amount of the standard sample or the sample to be tested is 16 - 20 μL, quantitative detection of blood potassium can be achieved. The rapid and convenient quantitative detection method for trace blood potassium described in the present invention has the characteristic of less sample consumption.

[0027] The present invention has confirmed through experiments that for a 3AA model standard resistance strain gauge with a size specification of 6.4 mm × 3.5 mm, a K + responsive hydrogel layer with a thickness of 0.3 mm is combined on the resistance strain gauge to form a K + responsive hydrogel strain sensor. After that, when a sample containing K + is evenly dropped onto the K + responsive hydrogel layer of the K + responsive hydrogel strain sensor, the microstrain measured by the Wheatstone bridge module integrated with the data acquisition device can reach stability in 2 - 4 minutes. The rapid and convenient quantitative detection method for trace blood potassium described in the present invention has the advantage of fast detection speed.

[0028] In the technical solution of the above-mentioned rapid and convenient quantitative detection method for trace blood potassium, after placing the K + responsive hydrogel strain sensor of the detection device on the hot stage, it should be ensured that there is no K + responsive hydrogel layer on one side of the K + responsive hydrogel strain sensor attached to the heating plane of the hot stage. Usually, the K + responsive hydrogel strain sensor is horizontally placed on the heating plane of the hot stage, with the K + responsive hydrogel layer facing up.

[0029] The principle of the present invention for realizing rapid and convenient quantitative detection of trace blood potassium based on the K + responsive hydrogel strain sensor is mainly as follows:

[0030] The K + responsive hydrogel strain sensor described in the present invention is obtained by bonding the K + responsive hydrogel layer to the substrate of the resistance strain gauge through chemical bonds and completely covering the sensitive grid wires of the resistance strain gauge. The substrate is a synthetic resin substrate modified by surface silanization. The K+ The gel polymer network of the responsive hydrogel layer is physically crosslinked by the linear polymer poly(N-isopropylacrylamide-co-4-acrylamidobenzo-15-crown-5) and the physical crosslinker Laponite XLG nanosheets.

[0031] K + The responsive hydrogel layer is obtained by photoinitiated polymerization of a gel prepolymer solution containing the functional monomer 4-acrylamidobenzo-15-crown-5, the gel monomer N-isopropylacrylamide, a photoinitiator, and the physical crosslinker Laponite XLG nanosheets. The 4-acrylamidobenzo-15-crown-5 monomer and the N-isopropylacrylamide monomer respectively provide K + recognition performance and temperature responsiveness to the hydrogel layer, thus endowing the hydrogel layer with unique sensing performance. Laponite XLG nanosheets are a kind of synthetic nanoclay composed of disc-shaped silicate particles, with a diameter of about 25 nm and a thickness of about 1 nm. Using Laponite XLG nanosheets as the physical crosslinker can effectively increase the spacing between the molecular chains of the gel network and reduce K + the steric hindrance during the transmission process, thus effectively accelerating the response time of the sensor and achieving rapid detection. Laponite XLG forms reversible electrostatic interactions and / or hydrogen bonds between the surface charges and the molecular chains of the gel network, rather than permanent covalent bonds. This dynamic crosslinking method allows the gel network to locally dissociate and reconstruct under external forces, thereby enhancing K + the strength and ductility of the responsive hydrogel, enabling it to exhibit good self-adaptability and fatigue resistance in complex environments. In the present invention, the surface of the substrate of the resistive strain gauge is modified by silanization. During the polymerization of the gel prepolymer solution to form K + the responsive hydrogel layer, covalent bonds will be formed with the silanized substrate, enhancing K + the binding stability between the responsive hydrogel layer and the resistive strain gauge, and avoiding the problem of failure caused by the detachment of the responsive hydrogel layer and the resistive strain gauge due to bending deformation during the detection process. +

[0032] On this basis, when K + the 15-crown-5 group in the responsive hydrogel layer comes into contact with K + in the serum, a specific recognition reaction will occur. 15-crown-5 and K + will form a stable "2:1" sandwich-like complex, making K + be accurately captured and fixed inside K + the responsive hydrogel layer. With the formation of the complex, the hydrogen bond between the crown ether and water molecules is broken, resulting in K +The three-dimensional network structure of the responsive hydrogel collapses, triggering K + The overall responsive hydrogel layer undergoes shrinkage deformation. Since K + The responsive hydrogel layer is tightly bonded to the resistive strain gauge, thus K + The shrinkage deformation of the responsive hydrogel layer will be transmitted to the resistive strain gauge, causing the resistive strain gauge to bend and deform, and further resulting in the complete deformation of the strain gauge, causing the sensitive grid wire to bend and shrink. The resistive strain gauge works based on the piezoresistive effect. The resistance of the resistive strain gauge changes with mechanical deformation (strain), and the resistance change of the resistive strain gauge has a linear relationship with the strain it undergoes. Therefore, K + The shrinkage deformation of the responsive hydrogel layer will cause a significant change in the resistance of the resistive strain gauge. Through a high-precision resistance detection device, the resistance change of this resistive strain gauge can be monitored in real time, and then its microstrain can be obtained. By measuring the microstrain value of the resistive strain gauge, the quantification of K in serum is achieved + , as Figure 14 shown

[0033] Compared with the prior art, the technical solution provided by the present invention has the following beneficial technical effects:

[0034] 1. The present invention provides a K + responsive hydrogel strain sensor, which consists of a K + responsive hydrogel layer and a resistive strain gauge. The resistive strain gauge includes a substrate, a sensitive grid wire, a covering layer, and leads. The substrate is a synthetic resin substrate modified by surface silanization; + The responsive hydrogel layer is bonded to the substrate by chemical bonds and completely covers the sensitive grid wire of the resistive strain gauge; the K + responsive hydrogel layer's gel polymer network is physically cross-linked by linear polymer poly(N-isopropylacrylamide-co-4-acrylamidobenzo-15-crown-5) and physical cross-linking agent Laponite XLG nanosheets. On the one hand, the present invention uses Laponite XLG nanosheets as the physical cross-linking agent, which can increase the spacing between the molecular chains of the gel network and reduce the + space barrier during the transmission process, thus effectively accelerating the response time of the sensor and achieving rapid detection. On the other hand, Laponite XLG forms reversible electrostatic interactions and / or hydrogen bonds with the molecular chains of the gel network through surface charges, rather than permanent covalent bonds. This dynamic cross-linking method allows the gel network to locally dissociate and reconstruct under external forces, thereby enhancing the + strength and ductility of the responsive hydrogel, enabling it to exhibit good self-adaptability and fatigue resistance in complex environments. On the other hand, the present invention modifies the surface of the substrate of the resistive strain gauge by surface silanization, so that K +The responsive hydrogel layer is covalently bonded to the substrate, which effectively enhances the binding stability between the two, thereby increasing the stability of detection and signal transmission. + The responsive hydrogel layer can realize the response to K + Quickly identify and K + The signal of the responsive hydrogel is accurately and efficiently transmitted to the resistance strain gauge, and the K in serum can be detected by identifying the change of micro-strain of the resistance strain gauge. + Rapid quantitative detection.

[0035] 2. The K of the present invention + The responsive hydrogel strain sensor is used in conjunction with a Wheatstone bridge module integrated data acquisition device. + The resistance strain gauge of the responsive hydrogel strain sensor can + The tiny deformation of the responsive hydrogel layer during the detection process is converted into an electrical signal output, and the signal is amplified and collected through the Wheatstone bridge module, which can not only improve the detection sensitivity, but also ensure the stability and reliability of the signal. The supporting equipment Wheatstone bridge module integrated data acquisition device is small in size, light in weight, has no complex components inside, is low in cost, and is easy to operate. Therefore, the K + Based on the responsive hydrogel strain sensor, blood potassium detection can be achieved without the need for large equipment and professional technical operators. It is particularly suitable for use in scenarios such as homes, primary medical units or on-site rapid testing.

[0036] 3. With the K of the present invention + Based on the responsive hydrogel strain sensor, the present invention also provides a method for rapid and convenient quantitative detection of trace blood potassium, which can achieve serum K under the condition of trace serum sample dosage (16-20 μL). +Rapid detection of concentration (2 min). The method of the present invention has significant advantages compared with the existing blood potassium detection methods, especially in terms of detection speed and sample consumption. Existing blood potassium detection methods, such as flame atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, and detection using an ion-selective electrode (ISE), although technically mature, have many limitations in practical applications. For example, flame atomic absorption spectrometry requires complex sample pretreatment steps and requires more than 2 mL of serum sample. The detection time of graphite furnace atomic absorption spectrometry usually ranges from several minutes to dozens of minutes. The detection accuracy of detection using an ion-selective electrode is easily interfered by other ions in the sample, and has high requirements for sample pretreatment. Another example is that common blood potassium detection test kits on the market are mainly used for laboratory analysis, with complex operations and long detection times. In contrast, the method of the present invention requires a trace amount of serum sample, greatly reducing the sample consumption, greatly improving the detection efficiency, and without complex sample pretreatment process, realizing rapid, efficient and convenient detection of blood potassium.

[0037] 4. The rapid, convenient and quantitative detection method for trace blood potassium of the present invention has a wide detection range and excellent anti-interference ability. In terms of the detection range, the method of the present invention can accurately detect K -6 in the concentration range of 10 + ~10 mmol / L, covering a variety of application scenarios from extremely low K + concentration to high K + concentration. In terms of anti-interference performance, the method of the present invention has excellent anti-interference ability against a variety of metal ions. Even in the presence of high concentrations of common metal ions such as sodium, calcium, and magnesium, the method can still maintain good detection accuracy. This characteristic enables the method of the present invention to effectively avoid interference from other ions when dealing with complex biological samples and ensure the accuracy of the detection results. In addition, the K + responsive hydrogel strain sensor relied on by the method of the present invention showed basically no performance degradation in 12 consecutive cyclic tests, demonstrating good cyclic use performance and stability. This characteristic not only helps to improve the detection efficiency, but also can reduce the detection cost, making it more economically advantageous in large-scale applications. Through its wide detection range, strong anti-interference ability and excellent cyclic use performance, the present invention provides an efficient, convenient and economical solution for blood potassium detection. Brief Description of the Drawings

[0038] Figure 1 Figure (a) is the SEM image of PNB-1 after freeze-drying, Figure 1 Figure (b) is the infrared spectra of PNB-1, B15C5Am, L-XLG and PNIPAm hydrogel.

[0039] Figure 2 are the tensile stress-strain curves of PNB-1, PNB-3, and PNB-5.

[0040] Figure 3 Figures (a) and (b) are the photos of PNB-1 in deionized water at different temperatures and in K + aqueous solution at different temperatures.

[0041] Figure 4 Figure (a) is the S T / S 0 variation curve of PNB-1 with temperature, Figure 4 Figure (b) is the R S variation curve of PNB-1 with temperature.

[0042] Figure 5 is the K + photos of the volume change of PNB-1, PNB-3, and PNB-5 in K

[0043] Figure 6 are the S t / S 0 variation curves of PNB-1, PNB-3, and PNB-5 with immersion time.

[0044] Figure 7 is a schematic diagram of the principle and process of surface silanization modification of the polyimide substrate.

[0045] Figure 8 Figure (a) is the XPS spectra of the unmodified PI substrate (Before modification) and the modified PI substrate (After modification), Figure 8 Figure (b) is the peak-fitting diagram of the Si 2p XPS spectrum of the modified PI substrate.

[0046] Figure 9 Figure (a) is the test result of the peel strength between the K + responsive hydrogel and the modified PI substrate, Figure 9 Figure (b) is the test result of the shear strength between the K + responsive hydrogel and the modified PI substrate.

[0047] Figure 10 Figure (a) is the photo of the deformation of the PNB-1 patch at different temperatures, Figure 10 Figure (b) is the photo of the deformation of the unmodified hydrogel patch at different temperatures.

[0048] Figure 11 is the K + schematic diagram of the structure of the K+ Responsive hydrogel layer, 2 - Resistance strain gauge, 3 - Sensitive grid wire.

[0049] Figure 12 It is a schematic structural diagram of a detection device for rapid, convenient and quantitative detection of trace potassium in blood. In the figure, 4 - Wire, 5 - Wheatstone bridge module integrated data acquisition device.

[0050] Figure 13 It is a schematic circuit diagram of a detection device for rapid, convenient and quantitative detection of trace potassium in blood.

[0051] Figure 14 This is based on K + Schematic diagram of the principle of potassium detection using a K-responsive hydrogel strain sensor.

[0052] Figure 15 Figure (a) shows the microstrain of the K-responsive hydrogel strain sensor with respect to the K + concentration (10 + ~10 -6 ~10 1 mmol / L). Figure 15 Figure (b) shows the microstrain of the K-responsive hydrogel strain sensor with respect to the K + concentration (1 - 9 mmol / L). + Figure (c) shows the microstrain of the K-responsive hydrogel strain sensor with respect to the detection time. Figure 15 Figure (c) shows the microstrain of the K-responsive hydrogel strain sensor with respect to the detection time. + Figure (c) shows the microstrain of the K-responsive hydrogel strain sensor with respect to the detection time.

[0053] Figure 16 This is the + microstrain of the K-responsive hydrogel strain sensor with respect to the detection time in K + aqueous solutions of different concentrations.

[0054] Figure 17 This is the + continuous detection performance of the K-responsive hydrogel strain sensor when the K + concentration increases from 0 to 9 mmol / L.

[0055] Figure 18 This is the microstrain of the K-responsive hydrogel strain sensor for identifying human serum samples with different K + concentrations under different dropping amounts. + Figure (a) shows the anti-interference detection performance of the K-responsive hydrogel strain sensor for K

[0056] Figure 19 aqueous solution and interference ion aqueous solution. + Figure (a) shows the anti-interference detection performance of the K-responsive hydrogel strain sensor for K + aqueous solution and interference ion aqueous solution. Figure 19 Figure (b) shows the+ Anti-interference detection performance of the responsive hydrogel strain sensor for mixed solutions of Na + , Mg 2+ , Ca 2+ and K + .

[0057] Figure 20 Figure (a) of Figure 20 + is the performance graph of the K + -responsive hydrogel strain sensor in cyclic detection in deionized water and K Figure 20 Figure (a) of Figure 20 + is the microstrain test result of the K + -responsive hydrogel strain sensor in cyclic detection in deionized water and K

[0058] Figure 21 Figure (a) is the microstrain corresponding to each standard specimen obtained at different detection temperatures, Figure 21 Figure (b) of Figure 21 + is the combined influence graph of temperature and blood potassium concentration on the detection of blood potassium by the K Figure 21 Figure (c) of Figure 21 + is the microstrain reference standard spectrum of the K + -responsive hydrogel strain sensor for detecting the concentration of K Detailed implementation mode

[0059] The following further illustrates the K + -responsive hydrogel strain sensor and the rapid and convenient quantitative detection method for trace blood potassium of the present invention through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the protection scope of the present invention. Those skilled in the art make some non-essential improvements and adjustments to the present invention according to the above invention content and conduct specific implementation, which still belongs to the protection scope of the present invention.

[0060] Example 1

[0061] In this example, K + -responsive hydrogels (PNB hydrogels) with different physical crosslinker contents were prepared.

[0062] (1) Preparation of gel prepolymer solution

[0063] Under ice bath conditions, the crosslinker Laponite XLG nanosheets (L-XLG) were added to deionized water and stirred for 6 h to obtain an L-XLG dispersion. L-XLG dispersions with concentrations of 0.01 mol / L, 0.03 mol / L, and 0.05 mol / L were prepared respectively.

[0064] The functional monomer benzo-15-crown-5-acrylamide (B15C5Am), the gel monomer N-isopropylacrylamide (NIPAm) monomer, and the photoinitiator 2,2-diethoxyacetophenone were added to the L-XLG dispersion, and stirred well to obtain a gel prepolymer solution. Three gel prepolymer solutions were prepared using L-XLG dispersions with L-XLG concentrations of 0.01 mol / L, 0.03 mol / L, and 0.05 mol / L. In each gel prepolymer solution, the concentration of B15C5Am was 0.1 mol / L, the concentration of NIPAm was 1 mol / L, the volume concentration of the photoinitiator was 0.2%, and the concentrations of L-XLG were 0.01 mol / L, 0.03 mol / L, and 0.05 mol / L, respectively.

[0065] (2) Preparation of K + Responsive hydrogel (PNB hydrogel)

[0066] The gel prepolymer solution was added to a mold, and ultraviolet light was applied above the mold for 10 min to initiate the polymerization reaction of the K + responsive hydrogel prepolymer solution, and the K + responsive hydrogel prepolymer solution was transformed into K + responsive hydrogel (with a thickness of 1 mm). Then, the mold was removed and the K + responsive hydrogel was washed with deionized water. According to the different concentrations of L-XLG in the K + responsive hydrogel prepolymer solution used, the K + responsive hydrogels were denoted as PNB-1, PNB-3, and PNB-5, corresponding to the cases where the concentrations of L-XLG were 0.01 mol / L, 0.03 mol / L, and 0.05 mol / L, respectively.

[0067] Comparative Example 1

[0068] In this comparative example, N-isopropylacrylamide hydrogel (PNIPAm hydrogel) was prepared.

[0069] (1) Under ice bath conditions, the crosslinking agent L-XLG was added to deionized water and stirred for 6 h to obtain an L-XLG dispersion with an L-XLG concentration of 0.01 mol / L. NIPAm and the photoinitiator 2,2-diethoxyacetophenone were added to the L-XLG dispersion and stirred until dissolved to obtain a gel prepolymer solution, where the concentration of the NIPAm monomer was 1 mol / L, the volume concentration of the photoinitiator was 0.2%, and the concentration of L-XLG was 0.01 mol / L.

[0070] (2) Preparation of poly-N-isopropylacrylamide hydrogel (PNIPAm hydrogel)

[0071] The prepolymer solution was added into a mold, and ultraviolet light was applied above the mold for 10 min to initiate the polymerization reaction of the gel prepolymer solution, converting the gel prepolymer solution into poly(N-isopropylacrylamide) hydrogel (with a thickness of 1 mm). Then, the mold was removed and the poly(N-isopropylacrylamide) hydrogel was washed with deionized water.

[0072] The PNB-1 prepared in Example 1 was freeze-dried and its cross-section was tested by scanning electron microscopy (SEM). The results are as Figure 1 shown in Figure (a). From the SEM image, the porous structure inside PNB-1 can be clearly observed. The existence of these porous structures provides favorable channels for the diffusion and transportation of K + , and can increase the specific surface area of PNB-1 and reduce the resistance of ion transport, improving the ion conduction performance of PNB-1.

[0073] Infrared spectroscopy tests were performed on PNB-1 (PNB hydrogel in the figure), B15C5Am (B15C5Ammonomer in the figure), L-XLG prepared in Example 1, and PNIPAm hydrogel prepared in Comparative Example 1. The results are as Figure 1 shown in Figure (b). The characteristic absorption peak of the stretching vibration of the C═C skeleton on the benzene ring of B15C5Am appears at 1515 cm -1 , and the characteristic absorption peak of the asymmetric stretching vibration of C-O on Ar-O-R is located at 1223 cm -1 . The characteristic absorption peak of L-XLG appears at 960 cm -1 , representing the absorption peak of the silanol group, and the peak at 640 cm -1 corresponds to the stretching vibration of Mg-O. The characteristic absorption peaks of poly(N-isopropylacrylamide) hydrogel appear at 1367 cm -1 and 1387 cm -1 . These peaks belong to the characteristic absorption peaks of isopropyl groups. The existence of these absorption peaks indicates that the NIPAM monomer has been successfully polymerized to form a temperature-responsive hydrogel network. In addition, the peak at 640 cm -1 is also related to the stretching vibration of Mg-O, which further confirms the existence of L-XLG in the poly(N-isopropylacrylamide) hydrogel. The Si-O bond in the poly(N-isopropylacrylamide) hydrogel and the K + responsive hydrogel has undergone a significant red shift, and its absorption peak has moved from a higher wavenumber to 1000 cm -1, which is mainly due to the chemical interaction between L-XLG and the monomer or polymer chain that changes the local chemical environment and affects the vibration frequency of the Si-O bond. This chemical interaction can not only enhance the mechanical properties of the hydrogel but also provide a more stable network structure for the hydrogel. The characteristic absorption peaks of B15C5Am, L-XLG, and PNIPAM are all at K + are clearly visible in the infrared spectrum of the responsive hydrogel.

[0074] To evaluate the mechanical properties of the K + responsive hydrogel prepared in Example 1, PNB-1, PNB-3, and PNB-5 were tested using a mechanical testing machine (model EZ-LX, Shimadzu). During the test, a 100N sensor was used to conduct a tensile test on PNB-1, PNB-3, and PNB-5 at a tensile rate of 20 mm / min to obtain their tensile stress-strain curves.

[0075] The tensile stress-strain curves of PNB-1, PNB-3, and PNB-5 are as Figure 2 shown, Figure 2 where 1% L-XLG, 3% L-XLG, and 5% L-XLG represent PNB-1, PNB-3, and PNB-5 respectively. The mechanical properties of the K + responsive hydrogel are significantly improved with the increase in the concentration of the cross-linking agent L-XLG. The tensile strength of PNB-1, PNB-3, and PNB-5 increases from 30 kPa to 55 kPa and 95 kPa, and their strain capacity also increases from 400% to 550% and 603%. This indicates that the addition of L-XLG not only enhances the strength of the K + responsive hydrogel but also improves its ductility. This is mainly attributed to the synergistic effect of the dynamic cross-linking characteristics and nano-enhancement effect of L-XLG. Specifically, L-XLG forms reversible electrostatic interactions and / or hydrogen bonds with the polymer molecular chains of the hydrogel through its surface charges (positive charges at the edges and negative charges on the surface), rather than permanent covalent bonds. This dynamic cross-linking mechanism enables the hydrogel network to dissociate and reconstruct locally under external forces, thereby enhancing the strength and ductility of the hydrogel. In addition, the interface between L-XLG and the polymer molecular chains of the hydrogel can effectively transfer stress, optimize the uniformity of the network, and delay the propagation of cracks, which is beneficial for it to exhibit higher toughness and fatigue resistance when facing complex stresses. The sliding friction and fracture of the dynamic bonds can also absorb a large amount of energy, further improving the toughness of the hydrogel.

[0076] Example 2

[0077] In this example, the effects of the test temperature and the K + concentration on the volume change of PNB-1 prepared in Example 1 were tested.

[0078] PNB-1 was immersed in deionized water and K + aqueous solution with a concentration of 0.2 mol / L respectively, and the volume change of PNB-1 was observed under different temperature conditions (24 - 40 °C). Specifically, the volume change was reflected by the change in the bottom area. + Figures (a) and (b) in Figure 3 are the photos of PNB-1 in deionized water at different temperatures and K + aqueous solution at different temperatures. As Figure 3 can be seen, in deionized water and K + aqueous solution, the volume of PNB-1 gradually decreases with the increase of temperature, which indicates that the K + responsive hydrogel provided by the present invention has temperature responsiveness. In addition, the presence of K + also has a significant impact on the volume change of PNB-1, indicating that K + and temperature act together on the volume change of the K + responsive hydrogel.

[0079] To more precisely describe the volume change of PNB-1 at different temperatures, the bottom area change rate (S T / S 0 ) of PNB-1 was measured. Among them, S T represents the bottom area of PNB-1 at a specific temperature, and S 0 represents the bottom area of PNB-1 at 24 °C. The results are shown in Figure 4 Figure (a). In the figure, pure water represents the test in deionized water, and 0.2M K + represents the test in 0.2 mol / L K + aqueous solution. To more intuitively reflect the enhancing effect of K + concentration on the volume change of PNB-1, the relative bottom area change (R S ) was introduced to estimate the influence of temperature on the response of PNB-1 to K + . The R S value is defined as the ratio of the S + / S T value in 0.2 mol / L K 0 aqueous solution to the S T / S 0 value in deionized water at each temperature. Through R S , the optimal operating temperature for detecting K + concentration can be determined. The results are shown in Figure 4 Figure (b). As Figure 4 can be seen, at 32 °C, the R S value is the minimum, indicating that at 32 °C, K+ The responsive hydrogel has the largest volume change, so 32 °C was selected as the optimal operating temperature for testing K + responsive hydrogels for K + concentration.

[0080] Example 3

[0081] At the optimal operating temperature determined in Example 2, the effect on the volume change of PNB-1, PNB-3, and PNB-5 prepared in Example 1 was tested. +

[0082] PNB-1, PNB-3, and PNB-5 were respectively immersed in K + aqueous solution with a concentration of 0.2 mol / L and a temperature of 32 °C, and the change in their volume with the soaking time was observed. The results are as + shown. Figure 5 Figure 5 Figures (a) to (c) represent PNB-5, PNB-3, and PNB-1 respectively. As the soaking time increases, the volume of each K + responsive hydrogel gradually decreases. At the same soaking time, as the content of the cross-linking agent L-XLG in the K + responsive hydrogel increases, the volume shrinkage degree of the K + responsive hydrogel gradually decreases. This indicates that the stronger cross-linking network in the K + responsive hydrogel hinders the rapid and extensive reaction to K + .

[0083] PNB-1, PNB-3, and PNB-5 were respectively immersed in K + aqueous solution with a concentration of 0.2 mol / L and a temperature of 32 °C. The bottom area (S + ) of the K + responsive hydrogel at a specific time point and the bottom area (S t ) at the starting time point were measured, and S 0 / S t was calculated. The change curve of S 0 / S t / S 0 with the soaking time was plotted. The results are as Figure 6 shown. Figure 6 Among them, 1% L-XLG, 3% L-XLG, and 5% L-XLG represent PNB-1, PNB-3, and PNB-5 respectively. The bottom area of PNB-5 decreased by 54% within 12 min, the reaction of PNB-3 was slightly faster, and the bottom area decreased by 61% within 10 min, while PNB-1 showed better reaction performance, and the bottom area decreased by 81% within 7 min. Thus, it can be seen that K +The lower the content of L-XLG in the responsive hydrogel, the + faster the reaction rate between the responsive hydrogel and K + .

[0084] Example 4

[0085] The surface of polyimide (PI) lacks active groups and has strong chemical inertness, making it difficult to closely adhere to the K + responsive hydrogel. To enhance the bonding between the PI substrate and the K + responsive hydrogel, in this example, the PI substrate is surface-modified by silanization to prepare a modified PI substrate. The principle and process schematic diagram of the modification are as shown in Figure 7 Figure, and the steps are as follows:

[0086] (1) Preparation of 3-(methacryloyloxy)propyltrimethoxysilane hydrolysis solution

[0087] Add the silane coupling agent 3-(methacryloyloxy)propyltrimethoxysilane to a sodium acetate buffer solution with pH = 5.2 to prepare a solution with a concentration of 1 wt%, and stir for 30 min to hydrolyze the methoxy groups of the silane coupling agent into hydroxyl groups, obtaining 3-(methacryloyloxy)propyltrimethoxysilane hydrolysis solution.

[0088] (2) Plasma treatment

[0089] Ultrasonically clean the flaky PI substrate in absolute ethanol for 30 min, take it out and dry it, then treat it with plasma for 5 min to further clean the surface of the PI substrate and introduce active functional groups including hydroxyl and carboxyl groups on the surface of the PI substrate.

[0090] (3) Grafting reaction

[0091] Completely immerse the plasma-treated PI substrate in the 3-(methacryloyloxy)propyltrimethoxysilane hydrolysis solution at 60 °C for 30 min. During this process, the silanol groups of 3-(methacryloyloxy)propyltrihydroxy silane react with the active functional groups on the surface of the PI substrate to form covalent bonds. Then take it out, dry it at 60 °C, then rinse it with absolute ethanol, and dry it again at 60 °C to obtain a surface-silanized modified PI substrate (modified PI substrate).

[0092] Perform X-ray photoelectron spectroscopy (XPS) tests on the unmodified PI substrate (Before modification) and the modified PI substrate (After modification). The results are as shown in Figure 8As shown in Figure (a), it can be seen from the figure that compared with the unmodified PI substrate, an obvious Si 2p peak appears in the XPS spectrum of the modified PI substrate, which confirms that the silane coupling agent has been successfully grafted onto the PI substrate. The deconvoluted spectrum of the Si 2p XPS spectrum of the modified PI substrate is as shown in Figure 8 Figure (b). This figure clearly shows three main components, which correspond to different chemical bonds, namely Si-O bond (100.9 eV), Si-C bond (100 eV) and Si-Si bond (99.2 eV). The appearance of the Si-O bond is related to the grafting of the silane coupling agent, that is, the siloxane bond in the 3-(methacryloyloxy)propyltrimethoxysilane molecule undergoes a condensation reaction with the hydroxyl groups on the surface of the PI substrate to form a chemical bond; the Si-C bond indicates the existence of a chemical bond between silicon and carbon on the surface of the PI substrate, and this bond may originate from the silicon-carbon double bond in the 3-(methacryloyloxy)propyltrimethoxysilane molecule, and these double bonds will participate in the reaction during the subsequent hydrogel polymerization process to enhance the binding between the PI substrate and the hydrogel; the S-Si bond indicates the direct connection between silicon and silicon on the surface of the PI substrate, which is related to the self-polymerization crosslinking of the 3-(methacryloyloxy)propyltrimethoxysilane molecule.

[0093] Example 5

[0094] In this example, prepare K + responsive hydrogel patch.

[0095] (1) Prepare the gel prepolymer solution

[0096] The operation is the same as step (1) of Example 1.

[0097] (2) Assemble the mold

[0098] In this step, a glass plate is used as the support bottom plate, and a polytetrafluoroethylene plate with a rectangular through-hole is used as the template. The shape and size of the rectangular through-hole on the template are the same as the shape and size of the substrate. A circular through-hole protruding outside the rectangular through-hole is also provided at a corner of the rectangular through-hole. The thickness of the template is 1 mm, and a transparent glass plate is used as the cover plate, and a through-hole is provided on the cover plate. The sizes of the support bottom plate, the mold and the cover plate are all larger than the size of the modified PI substrate.

[0099] Place the modified PI substrate prepared in Example 4 on a horizontally placed support bottom plate, place the template above the modified PI substrate, so that the modified PI substrate is completely located in the rectangular through-hole of the template. Horizontally place a cover plate above the template to completely cover the rectangular through-hole of the template and make the through-hole on the cover plate match the position of the circular through-hole on the template, that is, make the through-hole on the cover plate communicate with the circular through-hole on the template. Then fix the positions of the support bottom plate, the modified PI substrate, the mold and the cover plate, and the assembly of the mold is completed. There is a cuboid cavity in this mold.

[0100] (3) Polymerization reaction and post-treatment

[0101] Inject the gel prepolymer solution into the cuboid cavity of the mold through the through-hole on the cover plate and the circular through-hole on the template and fill it up. Apply ultraviolet light irradiation above the mold for 10 min to initiate the polymerization reaction of the gel prepolymer solution, convert the gel prepolymer solution into K + responsive hydrogel and bond it chemically with the modified PI substrate. Then carefully remove the cover plate, the template and the support bottom plate, and wash the K + responsive hydrogel with deionized water to obtain the K + responsive hydrogel patch.

[0102] According to the different concentrations of L-XLG in the gel prepolymer solution used, the prepared K + responsive hydrogel patches are respectively denoted as PNB-1 patch, PNB-3 patch and PNB-5 patch, and the three correspond to the cases where the concentrations of L-XLG are 0.01 mol / L, 0.03 mol / L and 0.05 mol / L respectively.

[0103] Comparative Example 2

[0104] The operation of this comparative example is basically the same as that of Example 5, except that the modified PI substrate is replaced with an unmodified PI substrate, and the concentration of L-XLG in the gel prepolymer solution used is 0.01 mol / L, and an unmodified hydrogel patch is prepared.

[0105] Example 6

[0106] Test the adhesion strength between the K + responsive hydrogel and the modified PI substrate on the K + responsive hydrogel patch prepared in Example 5 through a peel test and a lap shear test.

[0107] The peel test reflects the adhesion tightness between the two by measuring the force required to peel the K + responsive hydrogel from the modified PI substrate. The test results are as Figure 9As shown in Figure (a), as the concentration of the crosslinking agent L-XLG in the gel prepolymer solution increases, the adhesion strength between the two gradually increases. When the concentration of L-XLG increases from 0.01 mol / L to 0.03 mol / L and 0.05 mol / L, the adhesion strength between the two increases from 10 N m -1 to 24 N m -1 and 50 N m -1 .

[0108] The lap shear test measures the performance of the K + responsive hydrogel patch when the responsive hydrogel and the modified PI substrate are subjected to a shear force parallel to the interface direction. The test results are shown in + Figure (b). As the concentration of the crosslinking agent L-XLG in the gel prepolymer solution increases, the shear force between the K Figure 9 responsive hydrogel and the modified PI substrate gradually increases. When the concentration of L-XLG increases from 0.01 mol / L to 0.03 mol / L and 0.05 mol / L, the shear force between the two rapidly increases from 8.2 kPa to 16.5 kPa and 23.8 kPa. +

[0109] This example confirms through the peel test and the lap shear test that the bonding between the K + responsive hydrogel and the modified PI substrate is stable, which is mainly due to the formation of chemical bonding between the K + responsive hydrogel and the modified PI substrate.

[0110] Example 7

[0111] Test the deformation of the K + responsive hydrogel patch prepared in Example 5 at different temperatures.

[0112] Place the PNB-1 patch prepared in Example 5 and the unmodified hydrogel patch prepared in Comparative Example 2 in a high-precision temperature control device. Set the initial temperature to 28 °C. After stabilizing for 10 min, record the patch state through an image acquisition system. Then gradually increase the temperature to 32, 36, 40, 60 °C, and record the patch state at each temperature. The results are shown in Figure 10 . When the temperature increases from 28 °C to 60 °C, the PNB-1 patch significantly bends towards the hydrogel side due to the thermally induced shrinkage of the K + responsive hydrogel. During the entire deformation process, the K + responsive hydrogel and the modified PI substrate always remain firmly bonded together, as shown in Figure 10 ​As shown in Figure (a) of Figure 10 . However, for the unmodified hydrogel patch prepared in Comparative Example 2, during the process of the temperature rising from 28 °C to 60 °C, the bonding strength between the hydrogel and the PI substrate was insufficient to withstand the force generated by the shrinkage of the hydrogel, resulting in the hydrogel peeling off from the PI substrate, as shown in + Figure (b) of + . This example confirmed that by modifying the PI substrate and then bonding the hydrogel and the PI substrate through covalent bonds, the bonding strength between the hydrogel and the PI substrate can be effectively enhanced, providing an important basis for realizing the + concentration quantitative detection using the

[0113] Example 8

[0114] In this example, a + responsive hydrogel strain sensor and its preparation method are provided.

[0115] The + structural schematic diagram of the Figure 11 responsive hydrogel strain sensor is as shown in + , which is composed of a + responsive hydrogel layer 1 and a resistance strain gauge 2. The resistance strain gauge 2 includes a substrate, a sensitive grid wire 3, a cover layer and leads. The material of the sensitive grid wire is constantan alloy. The leads are located at both ends of the sensitive grid wire and are used to connect the sensitive grid wire to the measurement circuit. The substrate plays a role in fixing and supporting the sensitive grid wire 3, and the cover layer plays a role in protecting the sensitive grid wire 3. The substrate is a polyimide (PI) substrate modified by surface silanization; the + responsive hydrogel layer 1 is bonded to the substrate through chemical bonds and completely covers the sensitive grid wire 3 of the resistance strain gauge 2. The gel polymer network of the + responsive hydrogel layer 1 is physically crosslinked by a linear polymer poly(N-isopropylacrylamide-co-4-acrylamidobenzo-15-crown-5) and a physical crosslinking agent Laponite XLG nanosheets. The thickness of the

[0116] responsive hydrogel layer 1 is 0.3 mm. + The preparation method of the

[0117] (1) Surface silanization modification of the substrate of the resistance strain gauge

[0118] ① Prepare a hydrolysis solution of 3-(methacryloyloxy)propyltrimethoxysilane

[0119] The operation is the same as step (1) of Example 4.

[0120] ② Plasma treatment

[0121] The resistance strain gauge (specifically, a standard resistance strain gauge of model 3AA with a size specification of 6.4 mm × 3.5 mm) was ultrasonically cleaned in absolute ethanol for 30 min, taken out and dried, and then treated with plasma for 5 min to further clean the PI substrate surface of the resistance strain gauge and introduce active functional groups including hydroxyl and carboxyl groups on the PI substrate surface of the resistance strain gauge.

[0122] ③ Grafting reaction

[0123] The plasma-treated resistance strain gauge was completely immersed in a 3-(methacryloyloxy)propyltrimethoxysilane hydrolysis solution at 60 °C and kept for 30 min, then taken out, dried at 60 °C, subsequently rinsed with absolute ethanol, and dried again at 60 °C to complete the surface silanization modification of the substrate of the resistance strain gauge.

[0124] (2) Preparation of gel prepolymer solution

[0125] Under ice bath conditions, L-XLG was added to deionized water and stirred for 6 h to obtain an L-XLG dispersion, where the concentration of L-XLG was 0.01 mol / L. B15C5Am, NIPAm, and the photoinitiator 2,2-diethoxyacetophenone were added to the L-XLG nanosheet dispersion, and stirred and mixed thoroughly to obtain a gel prepolymer solution.

[0126] In the gel prepolymer solution, the concentration of B15C5Am was 0.1 mol / L, the concentration of NIPAm was 1 mol / L, the volume concentration of the photoinitiator was 0.2%, and the concentration of L-XLG was 0.01 mol / L.

[0127] (3) Assembly of the mold

[0128] In this step, a glass plate was used as the support bottom plate, and a polytetrafluoroethylene plate with a rectangular through-hole was used as the template. The shape and size of the rectangular through-hole on the template were consistent with the shape and size of the surface-silanized modified substrate. A circular through-hole protruding outside the rectangular through-hole was also provided at a corner of the rectangular through-hole. The thickness of the template was 0.3 mm, and a transparent glass plate was used as the cover plate with a through-hole provided on it. The sizes of the support bottom plate, the mold, and the cover plate were all larger than the size of the substrate of the resistance strain gauge.

[0129] The resistive strain gauge with its substrate surface modified by silanization obtained in step (1) is placed horizontally on the support base plate with the substrate surface modified by silanization facing upward. A template is placed above the resistive strain gauge such that the substrate surface modified by silanization is completely located within the rectangular through-hole of the template. A cover plate is placed horizontally above the template to completely cover the rectangular through-hole of the template and make the through-hole on the cover plate match the position of the circular through-hole on the template, that is, to make the through-hole on the cover plate communicate with the circular through-hole on the template. Then, the positions of the support base plate, the resistive strain gauge, the mold, and the cover plate are fixed, thus completing the assembly of the mold. There is a cuboid cavity in this mold.

[0130] (3) Polymerization reaction and post-treatment

[0131] The gel prepolymer solution is injected through the through-hole on the cover plate and the circular through-hole on the template and fills the cuboid cavity of the mold. Ultraviolet light is applied above the mold for 10 min to initiate the polymerization reaction of the gel prepolymer solution, converting the gel prepolymer solution into a K + responsive hydrogel and chemically bonding it to the substrate surface modified by silanization. Then, the cover plate, the template, and the support base plate are carefully removed, and the K + responsive hydrogel is washed with deionized water to obtain a K + responsive hydrogel strain sensor.

[0132] Example 9

[0133] In this example, a K + responsive hydrogel strain sensor and its preparation method are provided, which are basically the same as those in Example 8, except that the concentration of L-XLG in the gel prepolymer solution is 0.03 mol / L.

[0134] Example 10

[0135] This example provides a K + responsive hydrogel strain sensor and its preparation method, which are basically the same as those in Example 8, except that the concentration of L-XLG in the gel prepolymer solution is 0.05 mol / L.

[0136] Example 11

[0137] This example provides a detection device for rapid, convenient, and quantitative detection of trace blood potassium. The structural schematic diagram is shown in Figure 12 .

[0138] The detection device for rapid, convenient, and quantitative detection of trace blood potassium is composed of the K + responsive hydrogel strain sensor in Example 8 and a Wheatstone bridge module integrated data acquisition device 5. The K +The lead wire of the responsive hydrogel strain sensor is connected to the integrated data acquisition device 5 of the Wheatstone bridge module through the wire 4 via the welding connection structure. The circuit schematic diagram of the detection device is shown in Figure 13 , that is, connect K + The circuit schematic diagram after the responsive hydrogel strain sensor is connected to the Wheatstone bridge circuit is as shown in Figure 13 .

[0139] Example 12

[0140] This example provides a detection device for rapid and convenient quantitative detection of trace potassium in blood. The structural schematic diagram is shown in Figure 12 .

[0141] The detection device for rapid and convenient quantitative detection of trace potassium in blood is composed of the K + responsive hydrogel strain sensor in Example 9 and the integrated data acquisition device 5 of the Wheatstone bridge module. The lead wire of the K + responsive hydrogel strain sensor is connected to the integrated data acquisition device 5 of the Wheatstone bridge module through the wire 4 via the welding connection structure.

[0142] Example 13

[0143] This example provides a detection device for rapid and convenient quantitative detection of trace potassium in blood. The structural schematic diagram is shown in Figure 12 .

[0144] The detection device for rapid and convenient quantitative detection of trace potassium in blood is composed of the K + responsive hydrogel strain sensor in Example 10 and the integrated data acquisition device 5 of the Wheatstone bridge module. The lead wire of the K + responsive hydrogel strain sensor is connected to the integrated data acquisition device 5 of the Wheatstone bridge module through the wire 4 via the welding connection structure.

[0145] Example 14

[0146] Investigate the detection performance of the K + responsive hydrogel strain sensor provided in Examples 8-10 for K + .

[0147] (1) Prepare K -6 , 10 -5 , 10 -4 , 10 -3 , 10 -2 , 10 -1 , 10 0 and 10 1 mmol / L (mM) aqueous solutions of K + .

[0148] The K of the detection devices in Examples 11 to 13 was respectively + The responsive hydrogel strain sensors were completely immersed in the above K + aqueous solution samples with the same dosage for each sample and a temperature of 32 °C. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain corresponding to each sample was recorded. The results are as shown in Figure 15 Figure (a).

[0149] (2) Generally, the blood K + concentration is at the mmol / L level, and the normal range is 3.5 - 5.5 mmol / L. Therefore, K + aqueous solutions with concentrations of 1, 3, 5, 7, and 9 mmol / L (mM) were prepared.

[0150] The K of the detection devices in Examples 11 to 13 was respectively + The responsive hydrogel strain sensors were completely immersed in the above K + aqueous solution samples with the same dosage for each sample and a temperature of 32 °C. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain corresponding to each sample was recorded. The results are as shown in Figure 15 Figure (b).

[0151] (3) The K + responsive hydrogel strain sensors of the detection devices in Examples 11 to 13 were completely immersed in the K + aqueous solution with a concentration of 5 mmol / L. For each detection device, the dosage of the K + aqueous solution was the same and the temperature was 32 °C. The change of the microstrain (με) with time was recorded by the Wheatstone bridge module integrated with the data acquisition device. The results are as shown in Figure 15 Figure (c).

[0152] It can be seen from Figure 15 that the K + responsive hydrogel strain sensors prepared in Examples 8 to 10 showed different K + detection ranges, but all had a very wide K + detection range. Among them, the K + responsive hydrogel strain sensor prepared in Example 8 had the widest detection range, which was 10 -6 -10 mmol / L. The detection range of the K + responsive hydrogel strain sensor prepared in Example 9 was 10 -5 -10 mmol / L. The detection range of the K + responsive hydrogel strain sensor prepared in Example 10 was 10 -4~10mmol / L. K + When the concentration is in the range of 1 to 9 mmol / L, K + Microstrain and K of responsive hydrogel strain sensor + The concentration is linear. K prepared in Examples 8 to 10 + The variation degree of microstrain of the responsive hydrogel strain sensor gradually decreases. + The microstrain of the responsive hydrogel strain sensor is 5mmol / L K + The time to reach equilibrium in aqueous solution was 2.0min, 2.8min and 3.4min respectively, all of which could achieve rapid detection.

[0153] Embodiment 15

[0154] Study on K prepared in Example 8 + Responsive hydrogel strain sensor for rapid detection of K + Aspects of performance.

[0155] Prepare K at concentrations of 1, 3, 5, 7, and 9 mmol / L (mM) + The K of the detection device of Example 11 is respectively + The responsive hydrogel strain sensor was completely immersed in the above different concentrations of K + In the aqueous solution samples, the amount of each sample was the same and the temperature was 32°C. The change of microstrain (με) over time was recorded by the Wheatstone bridge module integrated data acquisition device. Figure 16 shown.

[0156] Depend on Figure 16 It can be seen that K + When the concentration is in the range of 1 to 9 mmol / L, K + The responsive hydrogel strain sensors all showed a fast response of 2.0 min, and the microstrain and K + The concentration is linearly related (see Figure 15 (b) of the figure). It shows that K prepared in Example 8 + Responsive hydrogel strain sensor can quickly and effectively detect K + concentration.

[0157] Example 16

[0158] Study on K prepared in Example 8 + Performance of responsive hydrogel strain sensors during continuous detection.

[0159] Prepare K at concentrations of 1, 3, 5, 7, and 9 mmol / L (mM) + The K of the detection device of Example 11 is +The responsive hydrogel strain sensor was completely immersed in 1 mmol / L K + aqueous solution. The temperature of the K + aqueous solution was 32 °C and it was maintained for 5.0 min. The change of microstrain (με) with time was recorded by the data acquisition device integrated with the Wheatstone bridge module. Then the above operation was repeated, and the concentration of the K + aqueous solution was increased to 3, 5, 7, 9 mmol / L in sequence. The results are as Figure 17 shown.

[0160] As can be Figure 17 seen, during the whole testing process of this embodiment, the microstrain of the K + responsive hydrogel strain sensor showed a progressive change trend closely related to the K + concentration increment, demonstrating excellent fast response characteristics. This indicates that the K + responsive hydrogel strain sensor can achieve rapid and efficient detection of the K + concentration.

[0161] Example 17

[0162] Examine the performance of the K + responsive hydrogel strain sensor prepared in Example 8 in the detection of trace serum samples.

[0163] The K + responsive hydrogel strain sensor of the detection device in Example 11 was placed on a hot stage at 32 °C. 10 μL of human serum sample with a K + concentration of 3.8 mmol / L at 32 °C was taken with a pipette and evenly dropped onto the K + responsive hydrogel layer of the K + responsive hydrogel strain sensor. After the microstrain (με) measured by the data acquisition device integrated with the Wheatstone bridge module reached stability, the microstrain corresponding to each sample was recorded. Then the dropping amount (12, 14, 16, 18, 20 μL) of the human serum sample with a K + concentration of 3.8 mmol / L was adjusted respectively, and the above operation was repeated. After that, the human serum sample with a K + concentration of 3.8 mmol / L was replaced with human serum samples with K + concentrations of 4.6, 5.4, 0 mmol / L, and the above operation was repeated.

[0164] Figure 18 shows the microstrain when the K + responsive hydrogel strain sensor identifies human serum samples with different K + concentrations under different dropping amounts. When the dosage of the human serum sample is 10 μL, the K +The responsive hydrogel strain sensor can already respond effectively to K in serum + ; when the dosage of human serum sample reaches 16 - 20 μL, for the human serum sample with a K + concentration of 3.8 - 5.4 mmol / L, the microstrain value of the K + responsive hydrogel strain sensor basically remains stable. This indicates that by using the K + responsive hydrogel strain sensor described in the present invention, only a single drop of serum sample with a volume of 16 - 20 μL is required to achieve quantitative detection of the K + concentration in the serum sample, which has extremely high application value in fields such as clinical detection.

[0165] Example 18

[0166] Examine the anti - interference detection performance of the K + responsive hydrogel strain sensor prepared in Example 8.

[0167] Under normal circumstances, in human serum, in addition to K + , Na + , Ca 2+ and Mg 2+ are the most common and relatively high - concentration metal ions, Li + , Cu 2+ , Zn 2+ and Fe 3+ belong to essential trace elements for the human body, while Ba 2+ and Pd 2+ are typical heavy metal ions harmful to human health. Based on this, these metal ions are selected as interfering ions for research. In a real - serum environment, the serum concentration range of Na + is 135 - 145 mmol / L, the concentration range of Ca 2+ is 2.25 - 2.75 mmol / L, and the concentration range of Mg 2+ is 0.8 - 1.0 mmol / L. The operations of this example are as follows:

[0168] (1) Prepare aqueous solutions of metal ions of Li + , Na + , Mg 2+ , Ca 2+ , Cu 2+ , Zn 2+ , Ba 2+ , Pd 2+ and Fe 3+ with concentrations of 1, 3, 5, 7, 9 mmol / L (mM) as interfering - ion aqueous solutions. Prepare an aqueous solution of K + with concentrations of 1, 3, 5, 7, 9 mmol / L (mM).

[0169] The K of the detection device in Example 11 + The responsive hydrogel strain sensor was completely immersed in the above various different concentrations of K + aqueous solution samples or various interfering ion aqueous solution samples. The dosage of each sample was the same and the temperature was 32°C. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain corresponding to each sample was recorded. During the test, the tests were carried out in the order of increasing ion concentration, and the same K was used for the same metal ion solution + responsive hydrogel strain sensing. The test results are as Figure 19 shown in Figure (a).

[0170] (2) Different concentrations of Na + , Mg + , and Ca 2+ were added to the aqueous solution of K 2+ with a concentration of 5 mmol / L to prepare mixed ion solutions

[0171] The K of the detection device in Example 11 + responsive hydrogel strain sensor was completely immersed in the above various different concentrations of mixed ion solution samples. The dosage of each sample was the same and the temperature was 32°C. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain corresponding to each sample was recorded. The same K was used for the mixed solution containing the same metal ion + responsive hydrogel strain sensing. The test results are as Figure 19 shown in Figure (b).

[0172] It can be seen from Figure 19 that for interfering metal ions with concentrations in the range of 1-9 mmol / L, the influence on the performance of K + responsive hydrogel strain sensing for detecting K + can be ignored, and the detection performance of the K + responsive hydrogel strain sensor is hardly affected by high-concentration interfering ions. The K + responsive hydrogel strain sensor exhibits excellent anti-interference performance when detecting the concentration of K +

[0173] Example 19

[0174] Examine the repeated detection performance of the K + responsive hydrogel strain sensor prepared in Example 8

[0175] Prepare two groups of samples, one group is deionized water and the other group is an aqueous solution of K + with a concentration of 5 mmol / L​

[0176] First, immerse the K of the detection device in Example 11 + The responsive hydrogel strain sensor was completely immersed in deionized water at 32 °C. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain was recorded. Then, the K + responsive hydrogel strain sensor was switched to K + in the aqueous solution. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain was recorded. Then, the K + responsive hydrogel strain sensor was switched back to deionized water. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reached stability, the microstrain was recorded. Repeat this process until 12 measurements are completed. The test results are as Figure 20 shown.

[0177] As Figure 20 can be seen, when the K + responsive hydrogel strain sensor was immersed in K + aqueous solution, its microstrain signal changed rapidly. At 2.0 min, the microstrain signal quickly rose and reached a stable level. After one detection of the K + aqueous solution was completed, the K + responsive hydrogel strain sensor was taken out and quickly immersed in deionized water. It can be observed that the microstrain signal of the K + responsive hydrogel strain sensor gradually decreased and returned to its initial state in deionized water in about 8 min. After switching back to the K + aqueous solution again, the microstrain curve quickly rose and tended to be stable. Then, after switching to deionized water, the microstrain curve gradually fell back to the initial baseline. During 12 cycles, the detection performance of the K + responsive hydrogel strain sensor remained stable all the time, proving the excellent repeated detection performance of the K + responsive hydrogel strain sensor in an alternating environment of different concentrations. This characteristic makes it have great application potential and value in fields such as clinical detection where extremely high precision and reliability are required for the detection of K + concentration.

[0178] Example 20

[0179] Investigate the performance of the K + responsive hydrogel strain sensor prepared in Example 8 in the detection of trace serum samples under different temperature conditions.

[0180] (1) Prepare standard samples

[0181] Prepare a series of K +Serum standard specimens with different concentrations, specifically: K + Human serum standard specimens with concentrations of 3.8, 4.6, and 5.4 mmol / L (mM).

[0182] (2) Determine K + Conversion relationship between concentration and microstrain

[0183] Place the K + responsive hydrogel strain sensor of the detection device in Example 11 on a hot stage at a temperature of 25 °C. According to the order of increasing K + concentration, use a pipette to successively take 20 μL of the standard specimen at 25 °C and evenly drop it onto the K + responsive hydrogel layer of the responsive hydrogel strain sensor. After the microstrain (με) measured by the Wheatstone bridge module integrated with the data acquisition device reaches stability, record the microstrain corresponding to each standard specimen. Using the microstrain corresponding to each standard specimen as the ordinate and the K + concentration of each standard specimen as the abscissa, plot a working curve to determine the conversion relationship between K + concentration and microstrain at a detection temperature of 25 °C, specifically: με = -115.39 × [K + -0.136. + ) and microstrain, specifically: με = -115.39 × [K + -0.136.

[0184] Replace with a new K + responsive hydrogel strain sensor. Referring to the above operation, obtain the conversion relationship between K + concentration and microstrain at a detection temperature of 30 °C, specifically: με = -143.37 × [K + -0.3052.

[0185] Replace with a new K + responsive hydrogel strain sensor. Referring to the above operation, obtain the conversion relationship between K + concentration and microstrain at a detection temperature of 32 °C, specifically: με = -163.23 × [K + -0.1209.

[0186] Replace with a new K + responsive hydrogel strain sensor. Referring to the above operation, obtain the conversion relationship between K + concentration and microstrain at a detection temperature of 35 °C, specifically: με = -173.56 × [K + +0.0799.

[0187] Replace with a new K + responsive hydrogel strain sensor. Referring to the above operation, obtain the conversion relationship between K +The conversion relationship between concentration and microstrain is: με=-197.3×[K + ]-5.0331.

[0188] (3) Blood potassium concentration detection of test samples

[0189] Replace with new K + The responsive hydrogel strain sensor replaces the standard sample in step (2) with the sample to be tested (serum sample), and measures the microstrain corresponding to the sample to be tested according to the operation of step (2). + The K of the sample to be tested is calculated using the conversion relationship between concentration and microstrain. + concentration.

[0190] The detection temperature used in step (3) is the same as the detection temperature used when drawing the working curve in step (2). + The K of the sample to be tested is calculated using the conversion relationship between concentration and microstrain. + When the concentration is determined, the K at the corresponding test temperature should be used. + The calculation is performed based on the conversion relationship between concentration and microstrain.

[0191] (4) K at different test temperatures + Responsive hydrogel strain sensor for detecting K in serum + Plotting of the microstrain reference standard spectrum of concentration

[0192] Considering the human serum K + The normal range of concentration is 3.5~5.5mmol / L. + Human serum with concentrations of 3.8, 4.6, and 5.4 mmol / L (mM) was used as samples for detection at different detection temperatures.

[0193] Replace with new K + Responsive hydrogel strain sensor, replace the standard sample in step (2) with the sample prepared in this step, and measure the microstrain corresponding to the sample according to the operation of step (2). + The microstrain of samples with concentrations of 3.8, 4.6, and 5.4 mmol / L at different test temperatures is shown in Figure 2. The test temperature is used as the horizontal axis, the microstrain is used as the vertical axis, and K is used as the vertical axis. + The microstrain corresponding to the sample with a concentration of 5.5mmol / L is taken as the upper limit of the normal range of microstrain, and K + The microstrain corresponding to the sample with a concentration of 3.8mmol / L is taken as the lower limit of the normal range of microstrain and plotted against K at different detection temperatures. + Responsive hydrogel strain sensor for detecting K in serum + Concentration of microstrain reference standard spectrum.

[0194] Figure 21 (a) The figure shows the microstrain corresponding to serum samples obtained at different detection temperatures. Figure 21 (b) The figure shows the combined effect of temperature and blood potassium concentration on the detection of blood potassium by the K + -responsive hydrogel strain sensor. Figure 21 (c) The figure shows the microstrain reference standard spectrogram of the K + -responsive hydrogel strain sensor for detecting K in serum. + concentration. Figure 21 (c) The figure shows the microstrain ranges corresponding to hyperkalemia, hypokalemia, and normal blood potassium at different detection temperatures, which can provide a basis for quickly judging whether the blood potassium level of serum samples is normal in subsequent clinical applications.

[0195] Example 21

[0196] In this example, a K + -responsive hydrogel strain sensor and its preparation method are provided.

[0197] The structure of the K + -responsive hydrogel strain sensor is basically the same as that of the K + -responsive hydrogel strain sensor in Example 8, except that: the substrate is an epoxy resin substrate modified by surface silanization; the thickness of the K + -responsive hydrogel layer 1 is 0.2 mm. + The preparation method of the K

[0198] -responsive hydrogel strain sensor is different from the preparation method of Example 8 only in that: the silane coupling agent used is vinyltriethoxysilane; in the gel prepolymer solution, the concentration of B15C5Am is 0.1 mol / L, the concentration of NIPAm is 0.5 mol / L, the volume concentration of the photoinitiator is 0.2%, and the concentration of L-XLG is 0.01 mol / L; the thickness of the template is 0.2 mm.

[0199] In this example, a K + -responsive hydrogel strain sensor and its preparation method are provided.

[0200] The structure of the K + -responsive hydrogel strain sensor is basically the same as that of the K + -responsive hydrogel strain sensor in Example 8, except that: the substrate is a phenolic resin substrate modified by surface silanization; the thickness of the K + -responsive hydrogel layer 1 is 1 mm. +The preparation method of the responsive hydrogel strain sensor is different from the preparation method of Example 8 only in that: the silane coupling agent used is vinyltris(2-methoxyethoxy)silane; in the gel prepolymer solution, the concentration of B15C5Am is 0.1 mol / L, the concentration of NIPAm is 2 mol / L, the volume concentration of the photoinitiator is 0.2%, and the concentration of L-XLG is 0.01 mol / L; the thickness of the template is 1 mm.

Claims

1. A K + The responsive hydrogel strain sensor is characterized in that: The strain sensor consists of K + The responsive hydrogel layer (1) and the resistance strain gauge (2) are composed of a substrate, a sensitive grid wire (3), a covering layer and a lead wire, wherein the substrate is a synthetic resin substrate with a surface silanized modified surface; K + The responsive hydrogel layer (1) is bonded to the substrate through chemical bonds and completely covers the sensitive grid wire (3) of the resistance strain gauge (2); the K + The gel polymer network of the responsive hydrogel layer (1) is formed by physical cross-linking of linear polymer poly (N-isopropylacrylamide-co-4-acrylamidebenzo-15-crown-5) and physical cross-linking agent Laponite XLG nanosheets.

2. According to claim 1, K + The responsive hydrogel strain sensor is characterized in that: K + The responsive hydrogel layer (1) is composed of K + Responsive hydrogel composition, K + The content of Laponite XLG nanosheets in the responsive hydrogel is 0.01-0.05 mol / L.

3. According to claim 2, K + The responsive hydrogel strain sensor is characterized in that: The K + The responsive hydrogel layer (1) is obtained by photoinitiated polymerization of a gel prepolymer solution. The gel prepolymer solution is obtained by fully dispersing a functional monomer 4-acrylamide benzo-15-crown-5, a gel monomer N-isopropylacrylamide and a photoinitiator in a Laponite XLG nanosheet dispersion solution. In the gel prepolymer solution, the molar ratio of benzo-15-crown-5-acrylamide to N-isopropylacrylamide is (0.05-0.2):1, and the concentration of the N-isopropylacrylamide monomer is 0.5-2 mol / L.

4. The K according to any one of claims 1 to 3. + The responsive hydrogel strain sensor is characterized in that: K + The thickness of the responsive hydrogel layer (1) is 0.2 to 1 mm.

5. The K according to any one of claims 1 to 3. + A responsive hydrogel strain sensor, wherein the resistance strain gauge (2) is a thin film resistance strain gauge.

6. The K according to any one of claims 1 to 3. + The responsive hydrogel strain sensor is characterized in that: The surface silanized synthetic resin substrate is obtained by grafting a synthetic resin substrate with a silane coupling agent containing a carbon-carbon double bond after the synthetic resin substrate is treated with plasma.

7. According to claim 6, K + The responsive hydrogel strain sensor is characterized in that: The silane coupling agent containing a carbon-carbon double bond includes 3-(methacryloxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane or γ-methacryloxypropyltrimethoxysilane.

8. The K according to any one of claims 1 to 3. + The responsive hydrogel strain sensor is characterized in that: The synthetic resin substrate includes a polyimide substrate, a phenolic resin substrate, a phenolic-acetal resin substrate, an epoxy resin substrate or a polyester resin substrate.

9. A rapid and convenient quantitative detection method for trace blood potassium, characterized in that: The following steps are involved: ① The K described in any one of claims 1 to 8 + The responsive hydrogel strain sensor is connected to a Wheatstone bridge module integrated data acquisition device (5) to form a detection device; ②Prepare a series of K + The concentration of standard samples is different, and the K + The responsive hydrogel strain sensor was placed on a hot stage and heated according to K + The concentration is in the order from low to high, toward K + K of responsive hydrogel strain sensor + Standard samples are uniformly dropped onto the responsive hydrogel layer in sequence, and after the microstrain measured by the Wheatstone bridge module integrated data acquisition device reaches stability, the microstrain corresponding to each standard sample is recorded; and a series of microstrains corresponding to the standard samples are obtained; The micro strain corresponding to each standard sample is taken as the ordinate, and the K + With concentration as the horizontal axis, draw a working curve to determine K + The conversion relationship between concentration and microstrain; ③Use the same K as step ① + Responsive hydrogel strain sensor replaces K after step ② + Responsive hydrogel strain sensor, or let the K after step ② be used + K of responsive hydrogel strain sensor + The responsive hydrogel layer returns to the state before the test in step ②; Replace the standard sample in step ② with the sample to be tested, and determine the microstrain corresponding to the sample to be tested according to the operation in step ②. + The K of the sample to be tested is calculated using the conversion relationship between concentration and microstrain. + concentration; In steps ②③, the temperature of the standard sample and the sample to be tested is controlled to be the same as the temperature of the hot stage, the temperature of the hot stage is controlled to be a constant value between 25 and 40°C, and the drop amounts of the standard sample and the sample to be tested are controlled to be the same, and the sample to be tested is a serum sample.

10. The method for rapid and convenient quantitative detection of trace blood potassium according to claim 9, characterized in that: In steps ②③, the amount of standard sample and test sample added should be at least K + The responsive hydrogel layer completely covers the

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