A reusable antibacterial dry electrode and its assembly method

Abstract

The present invention belongs to the technical field of the preparation of human-computer interaction dry electrodes, and particularly relates to a reusable antibacterial dry electrode and an assembly method thereof. For the first time, through a green chemical method without organic solvents, a PEDOT / PSS dispersion solution is first prepared at room temperature, and then the mass ratio of PEDOT / PSS and MPBCD is balanced, and the rigid conductive polymer PEDOT / PSS is rapidly assembled into a flexible, reusably conductive dry electrode film with adjustable bonding ability and reshaping ability in one step; wherein, the mass ratio of the two in the PEDOT / PSS dispersion is 1:3.8, and the mass ratio of the PEDOT / PSS solution and the MPBCD solution is 1:30. The prepared dry electrode has good conductivity and can be reused for a long time, is soft and has good adhesiveness, and also has excellent regeneration and antibacterial properties. EMG and EOG signals can be accurately measured according to their adhesiveness and skin compliance. By connecting wires, the film can be made into a sensor, which has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of dry electrode preparation, and particularly relates to a reusable antibacterial dry electrode and an assembly method thereof, which can achieve long-term antibacterial effect. Background Art

[0002] At present, gel electrodes are the main electrodes for obtaining surface bioelectrical potentials in the clinical environment of human-computer interaction. However, in long-term continuous monitoring, due to the volatilization of the liquid in the gel electrolyte and skin irritation, signal degradation is likely to occur. Therefore, efforts have been made to develop skin-friendly human-computer interaction dry electrodes for bioelectrical potential measurement.

[0003] The research work on dry contact electrodes focuses on soft conductive polymer composites and intrinsically conductive polymers because they can adapt to rough or even deformed skin. Conductive polymer composites are composed of elastomers and conductive nanofillers, such as metals, nanotubes, nanowires, and nanosheets. The conductive nanofillers are in the minority in the elastomer matrix, resulting in a small effective contact area between the conductive nanofillers and human skin. Therefore, the electrode-skin interface impedance is several orders of magnitude higher than that of commercial gel electrodes, and a significant impact on bioelectrical potential signals can be observed. The mismatch between the dry electrode and human skin may occur during body movement, and this situation can be improved if the dry electrode adheres to the human skin. Polymer composite patches with bionic microcolumn or suction cup-like structures can be stretchable and sticky. However, their adhesion to the skin is easily affected by sweat or dirt secreted on the skin, as well as the aggregation or contamination of the structures. In addition, the adhesion of these structures caused by suction will bring discomfort to the patients. There are also concerns about the toxicity of the nanofillers.

[0004] Conductive polymers can have a high contact area with human skin, biocompatibility, high conductivity, and inherent mechanical flexibility. Among them, poly(ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has received particular attention as a dry electrode. For example, a PEDOT / PSS film printed on paper or polyimide foil can be used as an EMG dry electrode. However, the signal quality is poor, and the electrode may delaminate from the skin because the PEDOT / PSS film does not have adhesiveness and stretchability. Greco et al. reported that an ethyl cellulose / PEDOT / PSS bilayer ultrathin film can adhere to the skin and can be used as an EMG dry electrode. However, due to the limited stretchability of the ethyl cellulose / PEDOT / PSS bilayer, the EMG signal is vulnerable to strain during muscle movement. In addition, it is very difficult to process ultrathin films. To obtain high-quality biopotential signals, dry electrodes should be conductive, biocompatible, stretchable, conformal, and self-adhesive to the skin. However, intrinsically conductive polymers are neither stretchable nor adhesive to the skin.

[0005] However, most high-performance electrodes may cause skin discomfort, and even trigger inflammation and itching. In addition, considering that electrodes are a good medium for microbial growth due to long-term contact with human skin or unhealthy indoor air quality, antibacterial properties are an important performance optimization for electrodes to inhibit bacterial growth and prevent bacterial infections. In addition, most materials are not disposable and may become electronic waste at the end of their service life, even harming the human body or polluting the environment. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a reusable antibacterial dry electrode and an assembly method thereof. The dry electrode has high conductivity and skin-conforming stretchability, has good adhesiveness under dry and wet skin conditions respectively, can generate high-quality epidermal biopotential signals, and can be made into a sensor by simply connecting wires. When directly adhered to the skin, both sensitivity and detection range are improved. Most importantly, the dry electrode exhibits excellent antibacterial properties and the preparation method is simple.

[0007] The technical solution adopted is as follows:

[0008] A reusable antibacterial dry electrode is rapidly assembled into a flexible, adjustable bonding capacity, and reshaping-use conductive dry electrode film at room temperature by PEDOT:PSS and chlorhexidine diacetate under solvent-free conditions, and then a dry electrode circuit is made by connecting wires; wherein, the mass ratio of the PEDOT:PSS solution to the chlorhexidine diacetate solution is 1:10 - 50.

[0009] An assembly method of a reusable antibacterial dry electrode, comprising the following specific steps:

[0010] (1) Dilute chlorhexidine diacetate into an aqueous solution with a concentration of 100 mM;

[0011] (2) Dissolve a certain amount of sodium polystyrene sulfonate in deionized water, stir evenly and divide it into two equal parts. In one part of the sodium polystyrene sulfonate aqueous solution, add 3,4-ethylenedioxythiophene and mix. In the other part of the sodium polystyrene sulfonate solution, add an oxidant and mix. Then mix the two solutions and add them to a three-necked flask, and simultaneously introduce nitrogen, and carry out mechanical stirring at room temperature;

[0012] Filter the obtained mixture, wash it with water, chloroform and acetone respectively to remove unreacted substances and low molecular weight products; dry the sample to obtain a product in powder form, and finally disperse the product in powder form in deionized water to obtain a stable poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution;

[0013] (3) Take the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution prepared in step (2), add it to the aqueous solution of chlorhexidine diacetate in step (1) and mix, and then centrifuge to separate and take out the precipitate;

[0014] (4) Put the taken-out precipitate into a mold to obtain a dry electrode.

[0015] Preferably, in step (2), the volume ratio of sodium polystyrene sulfonate to deionized water is 1:10 - 25; as a further preference, the volume ratio of sodium polystyrene sulfonate to deionized water is 2:25.

[0016] Preferably, in step (2), in one part of the sodium polystyrene sulfonate aqueous solution, the volume ratio of sodium polystyrene sulfonate to the added 3,4-ethylenedioxythiophene is 1 - 10:1.

[0017] Preferably, the oxidant in step (2) is any one or a mixture of sodium persulfate, ferric sulfate, and benzoyl peroxide.

[0018] Preferably, in step (2), when the two solutions are mixed and added to the three-necked flask, the mechanical stirring time is 20 - 30 h.

[0019] Preferably, in step (2), the mass ratio between the obtained poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate is 1:2.5 - 5.

[0020] Preferably, in the step (3), the mass ratio of the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution to the chlorhexidine diacetate aqueous solution is 1:10 - 50, and the further preferred ratio is 1:30.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] For the first time, the present invention rapidly assembles the rigid conductive polymer poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate into a flexible, adhesiveness-adjustable, and reshaping-useable conductive dry electrode film through a solvent method without organic solvents. It has good conductivity and can be used as a long-term skin dry electrode.

[0023] For the first time, the present invention enables the long-term repeated use of the chlorhexidine diacetate antibacterial film: the dry electrode film can be washed with water and ethanol, or can be reshaped and reused after high-temperature sterilization.

[0024] When the mass ratio between poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate in the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution obtained in the present invention is 1:3.8, and the mass ratio of the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution to the chlorhexidine diacetate aqueous solution is 1:30, the prepared reusable antibacterial dry electrode has the most excellent mechanical properties. Whether it is wet skin or dry skin, smooth skin or hairy skin, it has good adhesion on various skins, can be reshaped and reused, and EMG and EOG signals can be accurately measured according to its adhesion and skin compliance; by simply connecting wires, the film can be made into a sensor, which has strong sensitivity and a large detection range; most importantly, the film shows excellent antibacterial properties.

[0025] The assembly method of the reusable antibacterial dry electrode of the present invention is simple, the materials used are simple, the conditions are mild, and it is easy to realize industrialized scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the process flow chart for the preparation of the reusable antibacterial dry electrode of the present invention;

[0027] Figure 2 It is the interfacial adhesion of the dry electrode film of the present invention on different skins;

[0028] Figure 3 It is the comparison diagram of EMG signals generated by the normal use and reshaping and reuse of the dry electrode of the present invention;

[0029] Figure 4 It is the comparison diagram of EOG signals generated by the normal use and reshaping and reuse of the dry electrode of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The figures are only for illustrative purposes; for those skilled in the art, some well-known structures and their descriptions in the drawings may be omitted. Therefore, it should not be construed as a limitation to the present invention.

[0031] Example 1

[0032] As Figure 1 shown, a method for assembling a reusable antibacterial dry electrode includes the following specific steps:

[0033] (1) Dilute chlorhexidine diacetate into an aqueous solution with a concentration of 100 mM;

[0034] (2) Dissolve 8.0 mL of sodium polystyrene sulfonate in 100 mL of deionized water and divide it into two equal parts. In one part of the sodium polystyrene sulfonate aqueous solution, add 2.0 mL of EDOT and mix. In the other part of the sodium polystyrene sulfonate solution, add 4.5 g of benzoyl peroxide and mix. Then mix the two solutions and add them to a three-necked flask. At the same time, introduce nitrogen and carry out mechanical stirring at room temperature for 24 hours.

[0035] Filter the obtained mixture, wash it with water, chloroform, and acetone respectively to remove unreacted substances and low molecular weight products; dry the sample at 60 °C for 24 hours to obtain a product in powder form. Finally, disperse the product in powder form in water to obtain a stable poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution; the mass ratio between poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate is 1:3.8.

[0036] (3) Take the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution prepared in step (2) and add it to the aqueous solution of chlorhexidine diacetate in step (1). The mass ratio of the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution to the aqueous solution of chlorhexidine diacetate is 1:10.

[0037] (4) After instant precipitation, take out the precipitate and place it in a mold for shaping for 1 hour. The mold can be common industrial hydrophobic materials such as polytetrafluoroethylene / silicone rubber, and different thicknesses and shapes can be customized. The mold of the present invention is customized according to the required thickness.

[0038] The dry electrode film prepared in this example has a very low yield, is not easy to form a film, the formed film is easy to crack, has no flexibility, poor adhesion ability, and poor conductivity.

[0039] Example 2

[0040] A method for assembling a reusable antibacterial dry electrode includes the following specific steps:

[0041] (1) Dilute chlorhexidine diacetate to an aqueous solution with a concentration of 100 mM.

[0042] (2) Dissolve 8.0 mL of sodium polystyrene sulfonate in 100 mL of deionized water and divide it into two equal parts. In one part of the sodium polystyrene sulfonate aqueous solution, add 2.0 mL of EDOT and mix. In the other part of the sodium polystyrene sulfonate solution, add 4.5 g of benzoyl peroxide and mix. Then mix the two solutions and add them to a three-necked flask. At the same time, introduce nitrogen and carry out mechanical stirring at room temperature for 24 hours.

[0043] Filter the obtained mixture and wash it with water, chloroform, and acetone respectively to remove unreacted substances and low molecular weight products; dry the sample at 60 °C for 24 hours to obtain the product in powder form. Finally, disperse the product in powder form in water to obtain a stable poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution; the mass ratio between poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate is 1:3.8.

[0044] (3) Take the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution prepared in step (2) and add it to the aqueous solution of chlorhexidine diacetate in step (1) and mix. The mass ratio between the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution and the chlorhexidine diacetate aqueous solution is 1:20.

[0045] (4) Put the taken precipitate into a mold to obtain a dry electrode.

[0046] The dry electrode film prepared in this example has a relatively high yield, poor flexibility after film formation, good bonding ability, and good conductivity.

[0047] Example 3

[0048] A method for assembling a reusable antibacterial dry electrode, comprising the following specific steps:

[0049] (1) Dilute chlorhexidine diacetate to an aqueous solution with a concentration of 100 mM.

[0050] (2) Dissolve 8.0 mL of sodium polystyrene sulfonate in 100 mL of deionized water and divide it into two equal parts. In one part of the sodium polystyrene sulfonate aqueous solution, add 2.0 mL of EDOT and mix. In the other part of the sodium polystyrene sulfonate solution, add 4.5 g of benzoyl peroxide and mix. Then mix the two solutions and add them to a three-necked flask. At the same time, introduce nitrogen and carry out mechanical stirring at room temperature for 24 hours.

[0051] The obtained mixture was filtered and washed with water, chloroform, and acetone respectively to remove unreacted substances and low-molecular-weight products; the sample was dried at 60 °C for 24 hours to obtain the product in powder form, and finally the product in powder form was dispersed in water to obtain a stable poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution; the mass ratio between poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate was 1:3.8.

[0052] (3) Take the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution prepared in step (2) and add it to the aqueous solution of chlorhexidine diacetate in step (1) for mixing. The mass ratio of the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution to the aqueous solution of chlorhexidine diacetate is 1:30.

[0053] (4) Put the taken precipitate into a mold to obtain a dry electrode.

[0054] The dry electrode film prepared in this example has the highest yield, good film formation, no cracking, good flexibility, good conductivity, and antibacterial properties, and is the most preferred.

[0055] Example 4

[0056] A method for assembling a reusable antibacterial dry electrode includes the following specific steps:

[0057] (1) Dilute chlorhexidine diacetate into an aqueous solution with a concentration of 100 mM.

[0058] (2) Dissolve 8.0 mL of sodium polystyrene sulfonate in 100 mL of deionized water and divide it into two equal parts. In one part of the aqueous sodium polystyrene sulfonate solution, add 2.0 mL of EDOT for mixing. In the other part of the sodium polystyrene sulfonate solution, add 4.5 g of benzoyl peroxide for mixing. Then mix the two solutions and add them to a three-necked flask, and simultaneously introduce nitrogen, and carry out mechanical stirring at room temperature for 24 hours.

[0059] The obtained mixture was filtered and washed with water, chloroform, and acetone respectively to remove unreacted substances and low-molecular-weight products; the sample was dried at 60 °C for 24 hours to obtain the product in powder form, and finally the product in powder form was dispersed in water to obtain a stable poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution; the mass ratio between poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate was 1:3.8.

[0060] (3) Take the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution prepared in step (2) and add it to the aqueous solution of chlorhexidine diacetate in step (1) for mixing. The mass ratio of the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution to the aqueous solution of chlorhexidine diacetate is 1:50.

[0061] (4) Put the taken precipitate into a mold to obtain a dry electrode.

[0062] The dry electrode film prepared in this example has too poor strength and is too sticky, but has a good bactericidal effect. It shows that the more chlorhexidine diacetate, the better the bactericidal effect, but other properties are relatively weak and the use effect is not good.

[0063] Comparative Example 1

[0064] A dry electrode film was prepared using a pure poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate solution, but this method can basically not prepare a dry electrode film.

[0065] Test Example 1

[0066] The conformability and adhesion of the PPM film were tested and compared on ordinary skin, sweating skin (i.e., wet skin), hairy skin, hairy sweating skin, and finger joint skin. The adhesion was very good. As Figure 2 shown, the adhesion force of the dry electrode film attached to these skins was tested. Even the adhesion force on sweating skin reached 0.6 N / cm, and the adhesion force on finger joints was the largest, and the conformability was very good.

[0067] Test Example 2

[0068] The used dry electrode film was regenerated. The dry electrode films of the same size after being broken were soaked, regenerated, precipitated, and put into a mold to obtain new dry electrodes of the same size. As Figure 4 described, the EMG and EOG signals generated after reshaping were compared with those before reshaping. The signals before and after were basically overlapped, and it was impossible to distinguish their signal intensities, and the difference was very small.

[0069] Test Example 3

[0070] The antibacterial properties of the products prepared in Examples 1-3 and the blank example of Comparative Example 1 were tested. For Escherichia coli, Staphylococcus aureus clones, and Gram-positive bacteria in Table 1, and then in contact with dry electrode films with different chlorhexidine diacetate contents, the bactericidal ability was determined by checking the distance of the bacterial population from the material on the LB plate. I represents the blank sample, i.e., pure poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (dry electrode film prepared in Comparative Example 1); II is poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate:chlorhexidine diacetate = 1:10 (mass ratio, dry electrode film prepared in Example 1); III is poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate:chlorhexidine diacetate = 1:20 (mass ratio, dry electrode film prepared in Example 2); IV is poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate:chlorhexidine diacetate = 1:30 (mass ratio, dry electrode film prepared in Example 3).

[0071] Table 1 Comparison of the bactericidal ability of products with different proportions of chlorhexidine diacetate against different bacterial flora (radius of the bactericidal circle range)

[0072]

[0073]

[0074] As can be seen from Table 1, the film of pure poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate basically has no antibacterial property. The dry electrode film prepared with poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate:chlorhexidine diacetate = 1:30 has the largest antibacterial range, that is, the strongest antibacterial property.

[0075] Using the dry electrode film prepared in Example 3, it was cycled on the skin and reused after reshaping. The antibacterial ability test of the dry electrode at different cycle times is shown in Table 2.

[0076] Table 2 shows the antibacterial (Gram-positive bacteria) ability of dry electrodes at different cycle times

[0077]

[0078] As shown in Table 2, after being cycled 10 times, 50 times, 100 times, and 500 times respectively, the antibacterial ability is still very strong after being cycled 500 times. And after reshaping and being cycled 100 times and 500 times, the antibacterial property is still very strong.

[0079] The dry electrode film prepared in Example 3 was adhered to different skins respectively: normal skin, sweating skin, hairy skin, hairy and sweating skin, finger joints, etc. As Figure 2 shown, even on the hairy and sweating skin, the adhesion force reaches nearly 0.6 N / cm.

[0080] As Figure 3 shown, it is a comparison chart of the electromyogram potential signal (EMG) of the dry electrode film prepared in Example 3 on the skin during normal use and after reshaping. The signal is still very strong after reshaping.

[0081] As Figure 4 shown, it is a comparison chart of the potential signal (EOG) around the eyes of the dry electrode film prepared in Example 3 during normal use and after reshaping. The signal is also very strong after reshaping.

[0082] Meanings of English abbreviations in this application

[0083] EDOT: 3,4-ethylenedioxythiophene;

[0084] PEDOT: Polymer of EDOT, poly(3,4-ethylenedioxythiophene);

[0085] MPBCD: Chlorhexidine diacetate;

[0086] PSS: Sodium polystyrene sulfonate;

[0087] PPM: Dry electrode film assembled with PEDOT / PSS and MPBCD;

[0088] EMG: Electromyogram signal;

[0089] EOG: Electrooculogram signal.

[0090] Certainly, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the substantial scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for assembling a reusable antibacterial dry electrode, characterized in that, It includes the following specific steps: (1) Dilute chlorhexidine diacetate into an aqueous solution with a concentration of 100 mM; (2) Dissolve sodium polystyrene sulfonate in deionized water, stir evenly and divide it into two equal parts. In one part of the sodium polystyrene sulfonate aqueous solution, add 3,4-ethylenedioxythiophene and mix. In the other part of the sodium polystyrene sulfonate solution, add an oxidant and mix. Then mix the two solutions and add them to a three-necked flask, and simultaneously introduce nitrogen, and carry out mechanical stirring at room temperature; Filter the obtained mixture, wash it with water, chloroform and acetone respectively to remove unreacted substances and low molecular weight products; dry the sample to obtain a product in powder form, and finally disperse the product in powder form in deionized water to obtain a stable poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution; (3) Take the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution prepared in step (2), add it to the aqueous solution of chlorhexidine diacetate in step (1) and mix, and then centrifuge to obtain a precipitate and take it out; among them, the mass ratio of the poly(3,4-ethylenedioxythiophene) / sodium polystyrene sulfonate dispersion solution to the chlorhexidine diacetate aqueous solution is 1:10 - 50; (4) Put the taken-out precipitate into a mold to obtain a dry electrode.

2. The assembling method of a reusable antibacterial dry electrode according to claim 1, characterized in that, In step (2), the volume ratio of sodium polystyrene sulfonate to deionized water is 1:10 - 25.

3. The assembling method of a reusable antibacterial dry electrode according to claim 2, characterized in that, In step (2), in one part of the sodium polystyrene sulfonate aqueous solution, the volume ratio of sodium polystyrene sulfonate to the added 3,4-ethylenedioxythiophene is 1 - 10:

1.

4. A method for assembling a reusable antibacterial dry electrode according to claim 1, characterized in that, The oxidant in step (2) is any one or a mixture of sodium persulfate, ferric sulfate, and benzoyl peroxide.

5. The assembly method of a reusable antibacterial dry electrode according to claim 1, characterized in that, In step (2), when the two solutions are mixed and added to the three-necked flask, the mechanical stirring time is 20 - 30 h.

6. The assembly method of a reusable antibacterial dry electrode according to claim 1, characterized in that, In step (2), the mass ratio between the obtained poly(3,4-ethylenedioxythiophene) and sodium polystyrene sulfonate is 1:2.5 - 5.

7. An antibacterial dry electrode prepared by the assembly method of a reusable antibacterial dry electrode according to any one of claims 1 - 6.

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