Adhesive low-impedance skin electrode, application and preparation method thereof

Abstract

The invention discloses an adhesive low-impedance skin electrode as well as application and a preparation method thereof, relates to the technical field of biological electrodes, and aims to solve the problems that gel stimulates skin, the gel loses water along with time, so that the performance is reduced, and serious motion artifacts are generated due to sliding of the gel relative to the skin. The preparation method comprises the following steps: S1, preparing an MXene film; s2, preparing an adhesive film; and S3, preparing the skin electrode.

Description

Technical Field

[0001] The invention relates to the technical field of biological electrodes, and in particular to an adhesive low-impedance skin electrode, an application thereof and a preparation method thereof. Background Art

[0002] The human body is a collection of electrophysiological signals, including electrocardiogram, electromyography, electrooculography, and electroencephalography. The application of electrophysiological signals is of great significance to disease diagnosis, human-computer interaction, etc. At present, the acquisition of non-invasive electrophysiological signals in clinical medicine mainly relies on commercial silver-silver chloride gel electrodes. Although the interface impedance is low, there are also problems such as gel irritation to the skin, gel loss of water over time leading to performance degradation, and gel sliding relative to the skin causing serious motion artifacts. Therefore, in order to promote the development of electrophysiological signals in the fields of medicine and artificial intelligence, it is urgent to develop new adhesive, flexible, wearable, and low-impedance skin dry electrodes.

[0003] MXene is another new type of two-dimensional material after graphene, with many advantages such as simple preparation method, low cost, solution processability, rich and adjustable end groups, excellent electrical and electrochemical properties. Moreover, it has good self-supporting properties, which lays the foundation for its use as skin electrodes. Therefore, it is necessary to apply MXene to the preparation of skin electrodes. Summary of the invention

[0004] The present invention provides a method for preparing an adhesive low-impedance skin electrode, which comprises the following steps: S1: Preparation of MXene film: lithium fluoride is added to a hydrochloric acid solution, and then Ti3AlC2 (MAX phase) is slowly added, and after continuous stirring for reaction, deionized water is added, and centrifugation washing is repeated until the pH value of the supernatant reaches neutral, and then shear oscillation is performed under an inert gas atmosphere and centrifuged again to obtain a MXene aqueous dispersion, and the MXene aqueous dispersion is subjected to vacuum-assisted filtration to obtain a MXene film, and the MXene film is cut into a certain shape by laser cutting; S2: preparing an adhesive film: weighing a polydimethylsiloxane solution, a curing agent and a surfactant Triton X-100 in a certain mass ratio, mixing them at room temperature, and continuously stirring to obtain a uniform uncured solution; dropping the uncured solution on a target substrate, and spin coating it on a coating machine to obtain an uncured adhesive film; S3: Preparing skin electrodes: placing the patterned MXene film prepared in step S1 on the uncured adhesive film prepared in step S2, and then heating and curing them under a vacuum environment to cure the MXene film and the adhesive film together, and then peeling them off from the target substrate to obtain an adhesive low-impedance skin electrode.

[0005] The present invention is further configured as follows: in step S1, the mass ratio of lithium fluoride to Ti3AlC2 is 1.6:1, and the concentration of hydrochloric acid is 9 mol / L.

[0006] The present invention is further configured as follows: in the step S1, the MXene film is cut into one or more patterns of a circle, a rectangle, or a polygon.

[0007] The present invention is further configured as follows: in step S2, the mass ratio of the polydimethylsiloxane solution, the curing agent and the surfactant Triton X-100 is 10:1:0.2-10:1:0.5.

[0008] The present invention is further configured as follows: the target substrate in step S2 is one or more flexible polymer films.

[0009] The present invention is further configured as follows: the curing temperature in step S3 is 50-100° C., and the curing time is 20-120 min.

[0010] The present invention also proposes an adhesive low-impedance skin electrode, which is made by any of the preparation methods described above, and includes a MXene layer and an adhesive layer, and the MXene layer is cured on the adhesive layer by vacuum heating.

[0011] The present invention proposes an application of an adhesive low-impedance skin electrode, which can be applied to the collection of various electrophysiological signals such as electrocardiogram, electromyography, electrooculography, and electroencephalography, as well as smart medical treatment and human-computer interaction.

[0012] The beneficial effects of the present invention are:

[0013] 1. The adhesive skin electrode prepared by the present invention is non-toxic and biocompatible. It is prepared by spin coating and has the characteristics of self-adhesion. It can be well attached to the skin surface without additional conductive glue, has good conformability, and does not irritate the skin. The new low-dimensional material MXene used has excellent electrical and electrochemical properties, and the electrode can be in close contact with the skin. Therefore, the skin electrode has a lower skin interface impedance than the commercial silver chloride gel electrode, so it can obtain an electrophysiological signal with a higher signal-to-noise ratio.

[0014] 2. Since the skin electrode does not require the use of gel, there is no problem of performance degradation due to water loss, and it can be used repeatedly for a long time. Compared with disposable electrodes, it can save a lot of resources, and the preparation method is simple and quick, which is easier to mass produce and promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of Embodiment 1 is shown.

[0016] Figure 2 An optical picture of a low impedance skin electrode is shown.

[0017] Figure 3 A scanning electron micrograph of a cross section of a low-impedance skin electrode is shown.

[0018] Figure 4 A picture showing low impedance skin electrodes attached to the human body surface.

[0019] Figure 5 Shown is a graph comparing the interfacial impedance of a low impedance skin electrode to a commercial silver-silver chloride gel electrode.

[0020] Figure 6 Shows the acquisition of ECG signals by low impedance skin electrodes.

[0021] Figure 7 Shown is the acquisition of electromyographic signals by low impedance skin electrodes.

[0022] Figure 8 Shown is the collection of electrooculographic signals by low-impedance skin electrodes.

[0023] Fig. 9 Shows the acquisition of EEG signals using low impedance skin electrodes. DETAILED DESCRIPTION

[0024] Those skilled in the art can refer to the content of this article and appropriately improve the process parameters. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0025] Example 1

[0026] This embodiment provides a method for preparing an adhesive low-impedance skin electrode, comprising the following steps:

[0027] S1: Preparation of MXene film: lithium fluoride is added to a hydrochloric acid solution, and then Ti3AlC2 (MAX phase) is slowly added, and after continuous stirring for reaction, deionized water is added, and centrifugation washing is repeated until the pH value of the supernatant reaches neutral, and then shear oscillation is performed under an inert gas atmosphere and centrifuged again to obtain a MXene aqueous dispersion, and the MXene aqueous dispersion is subjected to vacuum-assisted filtration to obtain a MXene film, and the MXene film is cut into a certain shape by laser cutting;

[0028] S2: preparing an adhesive film: weighing polydimethylsiloxane, a curing agent and a surfactant Triton X-100 according to a certain mass ratio, mixing at room temperature, and continuously stirring to obtain a uniform uncured solution; dropping the uncured solution on a target substrate, and spin coating on a coating machine to obtain an uncured adhesive film;

[0029] S3: Preparing skin electrodes: placing the patterned MXene film prepared in step S1 on the uncured adhesive film prepared in step S2, and then heating and curing them under a vacuum environment to cure the MXene film and the adhesive film together, and then peeling them off from the target substrate to obtain an adhesive low-impedance skin electrode.

[0030] The mass ratio of lithium fluoride to Ti3AlC2 in step S1 is 1.6:1, and the concentration of hydrochloric acid is 9 mol / L.

[0031] In step S1, the MXene film is cut into one or more patterns of circular, rectangular, and polygonal shapes.

[0032] The mass ratio of polydimethylsiloxane, curing agent and surfactant Triton X-100 in step S2 is 10:1:0.2-10:1:0.5.

[0033] The target substrate in step S2 is one or more of PET, glass, silicon wafer or other flexible polymer films.

[0034] The curing temperature in step S3 is 50-100° C., and the curing time is 20-120 min.

[0035] Example 2

[0036] This embodiment provides an adhesive low-impedance skin electrode, which is made by the preparation method described in Example 1, and includes a MXene layer and an adhesive layer, and the MXene layer is cured on the adhesive layer by vacuum heating.

[0037] Example 3

[0038] This embodiment proposes an application of an adhesive low-impedance skin electrode as described in Embodiment 2, which can be applied to the collection of various electrophysiological signals such as electrocardiogram, electromyography, electrooculography, and electroencephalography, as well as smart medical treatment and human-computer interaction.

[0039] Example 4

[0040] This embodiment adopts the preparation method described in Example 1 to prepare an adhesive low-impedance skin electrode, and the specific steps are as follows:

[0041] S1: Preparation of MXene film: Use a measuring cylinder to measure 20 ml of 9 mol / L hydrochloric acid solution, pour it into a polytetrafluoroethylene reaction container, place it in a 50°C oil bath, continue magnetic stirring, accurately weigh 1.6 g of lithium fluoride powder and 1.0 g of Ti3AlC2 powder, slowly add lithium fluoride to hydrochloric acid, stir at 25°C for 15 min, then slowly add Ti3AlC2 powder, stir continuously at 25°C for 48 h, add 100 ml of deionized water, then centrifuge at 3500 rpm for 5 min, take the lower layer of precipitate, add deionized water again, repeat the centrifugation process until the pH value of the supernatant reaches neutral; then mix the lower layer of precipitate with 50 ml of deionized water, shear oscillate for 30 min under Ar atmosphere, centrifuge at 3500 rpm for 30 min again, take the upper layer of solution, and obtain a MXene aqueous dispersion solution.

[0042] Take 5 ml of the above MXene dispersion and add it to the filter cup for vacuum-assisted filtration. After two hours of filtration, a MXene film with a diameter of 45 mm is obtained. Then, it is cut using a laser with a power of 2 W and a cutting speed of 10 mm / s to cut the MXene film into small discs with a diameter of 10 mm.

[0043] S2: Preparation of adhesive film: 10.0 g of polydimethylsiloxane, 1.0 g of curing agent and 0.2 g of activator Triton X-100 were weighed in sequence, added into a 20 ml glass bottle at room temperature, and stirred continuously with a glass rod until a transparent and uniform solution, i.e., an uncured solution, was obtained.

[0044] The uncured solution was dropped onto a PET substrate and the substrate was placed on a spin coater and spin coated at 1500 rpm for 30 seconds to obtain an uncured adhesive film.

[0045] S3: Preparation of skin electrode: Place the small disc of MXene film obtained in step S1 on the uncured adhesive film prepared in step S2, and then take it out after curing it at 50°C in vacuum for 120 minutes, and gently peel off the cured adhesive film from the PET substrate to obtain an adhesive low-impedance skin electrode.

[0046] refer to Figure 1 This is the entire process diagram of this method; refer to Figure 2 The optical photograph of the adhesive low-impedance skin electrode prepared by this embodiment is shown in FIG. 1 . The present method can achieve close bonding between the MXene film and the adhesive substrate, and the scanning electron microscope morphology of the cross section is shown in FIG. Figure 3 As shown, the MXene film can be seen to be attached to the adhesive substrate; Figure 4 It can be seen that the adhesive low-impedance electrode prepared by the preparation method of this embodiment can be attached to the skin in a self-adhesive manner.

[0047] refer to Figure 5 , the impedance is as low as 9.5×10 at 10Hz 4 Ω, laying the foundation for obtaining high-quality electrophysiological signals.

[0048] refer to Figure 6 , which is an electrocardiogram signal collected by the skin electrode prepared in this embodiment, can show an obvious PQRST waveform, and the signal-to-noise ratio reaches 16.5dB, further illustrating its potential in the field of cardiovascular disease research.

[0049] Example 5

[0050] This embodiment adopts the preparation method described in Example 1 to prepare an adhesive low-impedance skin electrode, and the specific steps are as follows:

[0051] S1: Preparation of MXene film: Use a measuring cylinder to measure 20 ml of 9 mol / L hydrochloric acid solution, pour it into a polytetrafluoroethylene reaction container, place it in a 50°C oil bath, continue magnetic stirring, accurately weigh 1.6 g of lithium fluoride powder and 1.0 g of Ti3AlC2 powder, slowly add lithium fluoride to hydrochloric acid, stir at 30°C for 15 min, then slowly add Ti3AlC2 powder, stir continuously at 30°C for 36 h, add 100 ml of deionized water, then centrifuge at 5000 rpm for 4 min, take the lower layer of precipitate, add deionized water again, repeat the centrifugation process until the pH value of the supernatant reaches neutral; then mix the lower layer of precipitate with 50 ml of deionized water, shear oscillate for 30 min under N2 atmosphere, centrifuge at 3500 rpm for 30 min again, take the upper layer of solution, and obtain a MXene aqueous dispersion solution.

[0052] Take 5 ml of the above MXene dispersion and add it to the filter cup for vacuum-assisted filtration. After two hours of filtration, a MXene film with a diameter of 45 mm is obtained. Then, it is cut using a laser with a power of 2 W and a cutting speed of 10 mm / s to cut the MXene film into small discs with a diameter of 10 mm.

[0053] S2: Preparation of adhesive film: 10.0 g of polydimethylsiloxane, 1.0 g of curing agent and 0.3 g of activator Triton X-100 were weighed in sequence, added into a 20 ml glass bottle at room temperature, and stirred continuously with a glass rod until a transparent and uniform solution, i.e., an uncured solution, was obtained.

[0054] The uncured solution was dropped onto a PET substrate and the substrate was placed on a spin coater and spin coated at 1500 rpm for 30 seconds to obtain an uncured adhesive film.

[0055] S3: Preparation of skin electrode: Place the small disc of MXene film obtained in step S1 on the uncured adhesive film prepared in step S2, and then take it out after curing it at 70°C in vacuum for 100 minutes, and gently peel off the cured adhesive film from the PET substrate to obtain an adhesive low-impedance skin electrode.

[0056] refer to Figure 7 When making a fist, obvious electromyographic signals are shown.

[0057] Example 6

[0058] This embodiment adopts the preparation method described in Example 1 to prepare an adhesive low-impedance skin electrode, and the specific steps are as follows:

[0059] S1: Preparation of MXene film: Use a measuring cylinder to measure 20 ml of 9 mol / L hydrochloric acid solution, pour it into a polytetrafluoroethylene reaction container, place it in a 50°C oil bath, continue magnetic stirring, accurately weigh 1.6 g of lithium fluoride powder and 1.0 g of Ti3AlC2 powder, slowly add lithium fluoride to hydrochloric acid, stir at 40°C for 15 min, then slowly add Ti3AlC2 powder, stir continuously at 40°C for 24 h, add 100 ml of deionized water, then centrifuge at 8000 rpm for 3 min, take the lower layer of precipitate, add deionized water again, repeat the centrifugation process until the pH value of the supernatant reaches neutral; then mix the lower layer of precipitate with 50 ml of deionized water, shear oscillate for 30 min under He atmosphere, centrifuge at 3500 rpm for 30 min again, take the upper layer of solution, and obtain a MXene aqueous dispersion solution.

[0060] Take 5 ml of the above MXene dispersion and add it to the filter cup for vacuum-assisted filtration. After two hours of filtration, a MXene film with a diameter of 45 mm is obtained. Then, it is cut using a laser with a power of 2 W and a cutting speed of 10 mm / s to cut the MXene film into small discs with a diameter of 10 mm.

[0061] S2: Preparation of adhesive film: 10.0 g of polydimethylsiloxane, 1.0 g of curing agent and 0.4 g of activator Triton X-100 were weighed in sequence, added into a 20 ml glass bottle at room temperature, and stirred continuously with a glass rod until a transparent and uniform solution, i.e., an uncured solution, was obtained.

[0062] The uncured solution was dropped onto a PET substrate and the substrate was placed on a spin coater and spin coated at 1500 rpm for 30 seconds to obtain an uncured adhesive film.

[0063] S3: Preparation of skin electrode: Place the small disc of MXene film obtained in step S1 on the uncured adhesive film prepared in step S2, and then take it out after curing it at 90°C in vacuum for 60 minutes, and gently peel off the cured adhesive film from the PET substrate to obtain an adhesive low-impedance skin electrode.

[0064] refer to Figure 8 ,When blinking, obvious electrooculogram signals are collected, indicating that it can be used for intelligent applications such as eye tracking.

[0065] Example 7

[0066] This embodiment adopts the preparation method described in Example 1 to prepare an adhesive low-impedance skin electrode, and the specific steps are as follows:

[0067] S1: Preparation of MXene film: Use a measuring cylinder to measure 20 ml of 9 mol / L hydrochloric acid solution, pour it into a polytetrafluoroethylene reaction container, place it in a 50°C oil bath, continue magnetic stirring, accurately weigh 1.6 g of lithium fluoride powder and 1.0 g of Ti3AlC2 powder, slowly add lithium fluoride to hydrochloric acid, stir at 50°C for 15 min, then slowly add Ti3AlC2 powder, stir continuously at 50°C for 12 h, add 100 ml of deionized water, then centrifuge at 10000 rpm for 1 min, take the lower layer of precipitate, add deionized water again, repeat the centrifugation process until the pH value of the supernatant reaches neutral; then mix the lower layer of precipitate with 50 ml of deionized water, shear oscillate for 30 min under He atmosphere, centrifuge at 3500 rpm for 30 min again, take the upper layer of solution, and obtain a MXene aqueous dispersion solution.

[0068] Take 5 ml of the above MXene dispersion and add it to the filter cup for vacuum-assisted filtration. After two hours of filtration, a MXene film with a diameter of 45 mm is obtained. Then, it is cut using a laser with a power of 2 W and a cutting speed of 10 mm / s to cut the MXene film into small discs with a diameter of 10 mm.

[0069] S2: Preparation of adhesive film: 10.0 g of polydimethylsiloxane, 1.0 g of curing agent and 0.5 g of activator Triton X-100 were weighed in sequence, added into a 20 ml glass bottle at room temperature, and stirred continuously with a glass rod until a transparent and uniform solution, i.e., an uncured solution, was obtained.

[0070] The uncured solution was dropped onto a PET substrate and the substrate was placed on a spin coater and spin coated at 1500 rpm for 30 seconds to obtain an uncured adhesive film.

[0071] S3: Preparation of skin electrode: Place the small disc of MXene film obtained in step S1 on the uncured adhesive film prepared in step S2, then take it out after curing it at 100°C in vacuum for 20 minutes, and gently peel off the cured adhesive film from the PET substrate to obtain an adhesive low-impedance skin electrode.

[0072] refer to Fig. 9 The electrode position adopts the international 10-20 electrode system and is located at the Fp1 site on the forehead, indicating its application in fields such as EEG interface.

[0073] In summary, the adhesive skin electrode prepared by the present invention is non-toxic, has good biocompatibility, is prepared by spin coating, has the characteristics of self-adhesion, can be well attached to the skin surface without additional conductive glue, has good conformability, and does not irritate the skin. The new low-dimensional material MXene used has excellent electrical and electrochemical properties, and the electrode can be in close contact with the skin. Therefore, the skin electrode has a lower skin interface impedance than the commercial silver chloride gel electrode, so it can obtain an electrophysiological signal with a higher signal-to-noise ratio.

[0074] Since the skin electrode does not require the use of gel, there is no problem of performance degradation due to water loss, and it can be used repeatedly for a long time. Compared with disposable electrodes, it can save a lot of resources. The preparation method is simple and quick, and it is easier to mass produce and promote.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be within the scope of protection of the present invention.

Claims

1. A method for preparing an adhesive low-impedance skin electrode, characterized in that: The following steps are included: S1: Preparation of MXene film: lithium fluoride is added to a hydrochloric acid solution, and then Ti3AlC2 (MAX phase) is slowly added. After continuous stirring for reaction, deionized water is added, and centrifugation washing is repeated until the pH value of the supernatant reaches neutral, and then shear oscillation is performed under an inert gas atmosphere and centrifuged again to obtain a MXene aqueous dispersion, and the MXene aqueous dispersion is subjected to vacuum-assisted filtration to obtain a MXene film, and the MXene film is cut into a certain shape by laser cutting; S2: preparing an adhesive film: weighing a polydimethylsiloxane solution, a curing agent and a surfactant Triton X-100 in a certain mass ratio, mixing them at room temperature, and continuously stirring to obtain a uniform uncured solution; Dropping the uncured solution onto the target substrate, and obtaining an uncured adhesive film after spin coating on a spin coater; S3: Preparing skin electrodes: placing the patterned MXene film prepared in step S1 on the uncured adhesive film prepared in step S2, and then heating and curing them under a vacuum environment to cure the MXene film and the adhesive film together, and then peeling them off from the target substrate to obtain an adhesive low-impedance skin electrode.

2. The method for preparing an adhesive low-impedance skin electrode according to claim 1, characterized in that: In step S1, the mass ratio of lithium fluoride to Ti3AlC2 is 1.6:1, and the concentration of hydrochloric acid is 9 mol / L.

3. The method for preparing an adhesive low-impedance skin electrode according to claim 1, characterized in that: In the step S1, the MXene film is cut into one or more patterns of circular, rectangular, and polygonal shapes.

4. The method for preparing an adhesive low-impedance skin electrode according to claim 1, characterized in that: In the step S2, the mass ratio of the polydimethylsiloxane solution, the curing agent and the surfactant Triton X-100 is 10:1:0.2-10:1:0.

5.

5. The method for preparing an adhesive low-impedance skin electrode according to claim 1, characterized in that: The target substrate in step S2 is one or more flexible polymer films.

6. The method for preparing an adhesive low-impedance skin electrode according to claim 1, characterized in that: The curing temperature in step S3 is 50-100° C., and the curing time is 20-120 min.

7. An adhesive low impedance skin electrode, characterized in that: It is made by the preparation method as described in any one of 1-6 above, and includes a MXene layer and an adhesive layer, and the MXene layer is cured on the adhesive layer by vacuum heating.

8. A use of the adhesive low impedance skin electrode as claimed in claim 7, characterized in that: It can be applied to the collection of various electrophysiological signals such as electrocardiogram, electromyography, electrooculography, and electroencephalography, as well as smart medical treatment and human-computer interaction.

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