Reusable antibacterial dry electrode and assembling method thereof

Abstract

The invention belongs to the technical field of man-machine interaction dry electrode preparation, and particularly relates to a reusable antibacterial dry electrode and an assembly method thereof. According to the preparation method, a PEDOT / PSS dispersion solution is prepared at room temperature through an organic-solvent-free green chemical method for the first time, then the mass ratio of PEDOT / PSS to MPBCD is balanced, and rigid conductive polymer PEDOT / PSS is rapidly assembled into a conductive dry electrode film which is flexible, adjustable in bonding capacity and capable of being remolded for use in one step; wherein the mass ratio of PEDOT to PSS in the PEDOT / PSS dispersion liquid is 1: 3.8, the mass ratio of the PEDOT / PSS solution to the MPBCD solution is 1: 30, and the prepared dry electrode has good conductivity, can be repeatedly used for a long time, is soft and good in cohesiveness, and also has excellent regeneration and antibacterial properties. The EMG and EOG signals can be accurately measured according to the adhesion and skin compliance, and the sensor can be prepared by connecting a lead and a film, so that the sensor has a wide application prospect.

Description

Technical Field

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

[0002] At present, gel electrodes are the main electrodes for obtaining surface biopotentials in human-computer interaction clinical environments, but in long-term continuous monitoring, the signal is easily degraded due to the volatilization of the liquid in the gel electrolyte and skin irritation. Therefore, people are committed to developing skin-friendly human-computer interaction dry electrodes for biopotential measurement.

[0003] Research efforts on dry contact electrodes have focused on soft conductive polymer composites and intrinsically conductive polymers because they adapt to rough and even deformed skin. Conductive polymer composites consist 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. As a result, the electrode-skin interface impedance is several orders of magnitude higher than that of commercial gel electrodes, and a significant effect on the biopotential signal can be observed. The mismatch between dry electrodes and human skin can occur during body movements, which can be improved if the dry electrodes are adhered to human skin. Polymer composite patches with biomimetic micropillar or suction cup-like structures can be stretchable and sticky. However, their adhesion to the skin is easily affected by sweat secreted or dirt on the skin and by the aggregation or contamination of the structures. In addition, the adhesion of these structures caused by suction can cause discomfort to the patient. There are also concerns about the toxicity of the nanofillers.

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

[0005] However, most high-performance electrodes may cause skin discomfort, even inflammation and itching. In addition, considering that electrodes are good media for microbial growth due to long-term contact with human skin or unhealthy indoor air quality, antibacterial properties are important performance optimizations for electrodes to inhibit bacterial growth and prevent bacterial infection. 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 its assembly method, wherein the dry electrode has high conductivity and conforms to the stretchability of the skin, has good adhesion under dry and wet skin conditions, can generate high-quality epidermal biopotential signals, and by simply connecting wires, the film can be made into a sensor, and when directly adhered to the skin, the sensitivity and detection range are improved. Most importantly, the dry electrode shows excellent antibacterial properties and the preparation method is simple.

[0007] The technical solutions adopted are:

[0008] A reusable antibacterial dry electrode is prepared by rapidly assembling PEDOT / PSS and MPBCD (chlorhexidine diacetate) under solvent-free conditions at room temperature into a flexible, adhesively adjustable, reshapeable conductive dry electrode film, which is then connected with a wire to form a dry electrode; wherein the mass ratio of the PEDOT / PSS solution to the MPBCD solution is 1:10-50.

[0009] A method for assembling a reusable antibacterial dry electrode comprises the following specific steps:

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

[0011] (2) A certain amount of PSS was dissolved in deionized water, stirred evenly and divided into two equal parts. EDOT was added to one PSS aqueous solution and mixed. An oxidant was added to the other PSS solution and mixed. The two solutions were then mixed and added to a three-necked flask. Nitrogen was introduced at the same time and mechanically stirred at room temperature.

[0012] 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 to obtain a product in powder form, and finally the powder product was dispersed in deionized water to obtain a stable PEDOT / PSS dispersion solution;

[0013] (3) taking the PEDOT / PSS dispersed solution prepared in step (2), adding it to the MPBCD aqueous solution in step (1) and mixing until the precipitation no longer increases, centrifuging for 5 to 10 minutes, and taking out the precipitate;

[0014] (4) Place the removed precipitate into a mold to obtain a dry electrode.

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

[0016] Preferably, in step (2), in one portion of the PSS aqueous solution, the volume ratio of PSS to the added EDOT is 1 to 10:1, and as a further preferred ratio, the ratio is 2:1.

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

[0018] Preferably, in step (2), the two solutions are mixed and added into a three-necked flask, and the mechanical stirring time, i.e., the reaction time, is 20 to 30 hours, preferably 24 hours.

[0019] Preferably, in step (2), the mass ratio of the obtained PEDOT to PSS is 1:2.5-5; as a further preference, the ratio is 1:3.8.

[0020] Preferably, in step (3), the mass ratio of the PEDOT / PSS dispersed solution to the MPBCD aqueous solution is 1:10-50, and the more preferred ratio is 1:30.

[0021] Compared with the prior art, the present invention is beneficial in that:

[0022] The present invention is the first to use an organic solvent-free solvent method to rapidly assemble the rigid conductive polymer PEDOT / PSS into a flexible, adhesively adjustable, reshapeable conductive dry electrode film in one step, which has good conductivity and can be used as a long-term skin dry electrode.

[0023] This invention allows the MPBCD sterilization film to be reused for a long time for the first time: the dry electrode film can be reshaped and reused after washing with water and ethanol, or after high-temperature sterilization;

[0024] The PEDOT / PSS dispersed solution obtained by the present invention has a mass ratio of PEDOT to PSS of 1:3.8, and a mass ratio of the PEDOT / PSS dispersed solution to the MPBCD aqueous solution of 1:30. The prepared reusable antibacterial dry electrode has the best mechanical properties, has good adhesion to all kinds of skin, whether wet skin or dry skin, smooth skin or hairy skin, 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, and the sensor 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 industrialized scale-up production can be easily realized. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0028] Figure 3 A comparison diagram of EMG signals generated by the dry electrode of the present invention when it is used normally and reused after being reshaped;

[0029] Figure 4 This is a comparison diagram of EOG signals generated by the dry electrode of the present invention when it is used normally and reused after being reshaped. DETAILED DESCRIPTION

[0030] The figures are only used for exemplary description; for those skilled in the art, some well-known structures and their descriptions in the figures may be omitted, and therefore, they should not be understood as limitations on the present invention.

[0031] Example 1

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

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

[0034] (2) 8.0 mL of PSS was dissolved in 100 mL of deionized water and divided into two equal parts. 2.0 mL of EDOT was added to one portion of the PSS aqueous solution and mixed. 4.5 g of benzoyl peroxide was added to the other portion of the PSS solution and mixed. The two solutions were then mixed and added to a three-necked flask. Nitrogen was introduced at the same time and mechanically stirred at room temperature for 24 hours.

[0035] The resulting 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 a product in powder form, and finally the powder product was dispersed in water to obtain a stable PEDOT / PSS dispersed solution; the mass ratio between PEDOT and PSS was 1:3.8.

[0036] (3) Take the PEDOT / PSS dispersed solution prepared in step (2), add it to the MPBCD aqueous solution in step (1) and mix the PEDOT / PSS dispersed solution to the MPBCD aqueous solution in a mass ratio of 1:10.

[0037] (4) After the precipitation is formed instantly, the precipitation is taken out and placed in a mold to be shaped for 1 hour. The mold can be made of common industrial hydrophobic materials such as polytetrafluoroethylene / silicone, and can be customized with different thicknesses and different shapes. The present invention is a mold customized according to the required thickness.

[0038] The dry electrode film prepared in this embodiment has a very low yield, is not easy to form a film, is prone to cracking, has no flexibility, has relatively poor bonding ability, and has relatively poor conductivity.

[0039] Example 2

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

[0041] (1) Dilute MPBCD into an aqueous solution with a concentration of 100 mM.

[0042] (2) 8.0 mL of PSS was dissolved in 100 mL of deionized water and divided into two equal parts. 2.0 mL of EDOT was added to one portion of the PSS aqueous solution and mixed. 4.5 g of benzoyl peroxide was added to the other portion of the PSS solution and mixed. The two solutions were then mixed and added to a three-necked flask. Nitrogen was introduced at the same time and mechanically stirred at room temperature for 24 hours.

[0043] The resulting 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 a product in powder form, and finally the powder product was dispersed in water to obtain a stable PEDOT / PSS dispersed solution; the mass ratio between PEDOT and PSS was 1:3.8.

[0044] (3) Take the PEDOT / PSS dispersed solution prepared in step (2), add it to the MPBCD aqueous solution in step (1) and mix them, wherein the mass ratio of the PEDOT / PSS dispersed solution to the MPBCD aqueous solution is 1:20.

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

[0046] The dry electrode film prepared in this embodiment has a 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 comprises the following specific steps:

[0049] (1) Dilute MPBCD into an aqueous solution with a concentration of 100 mM.

[0050] (2) 8.0 mL of PSS was dissolved in 100 mL of deionized water and divided into two equal parts. 2.0 mL of EDOT was added to one portion of the PSS aqueous solution and mixed. 4.5 g of benzoyl peroxide was added to the other portion of the PSS solution and mixed. The two solutions were then mixed and added to a three-necked flask. Nitrogen was introduced at the same time and mechanically stirred at room temperature for 24 hours.

[0051] The resulting 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 a product in powder form, and finally the powder product was dispersed in water to obtain a stable PEDOT / PSS dispersed solution; the mass ratio between PEDOT and PSS was 1:3.8.

[0052] (3) Take the PEDOT / PSS dispersed solution prepared in step (2), add it to the MPBCD aqueous solution in step (1) and mix them, wherein the mass ratio of the PEDOT / PSS dispersed solution to the MPBCD aqueous solution is 1:30.

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

[0054] The dry electrode film prepared in this embodiment 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 comprises the following specific steps:

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

[0058] (2) 8.0 mL of PSS was dissolved in 100 mL of deionized water and divided into two equal parts. 2.0 mL of EDOT was added to one portion of the PSS aqueous solution and mixed. 4.5 g of benzoyl peroxide was added to the other portion of the PSS solution and mixed. The two solutions were then mixed and added to a three-necked flask. Nitrogen was introduced at the same time and mechanically stirred at room temperature for 24 hours.

[0059] The resulting 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 a product in powder form, and finally the powder product was dispersed in water to obtain a stable PEDOT / PSS dispersed solution; the mass ratio between PEDOT and PSS was 1:3.8.

[0060] (3) Take the PEDOT / PSS dispersed solution prepared in step (2), add it to the MPBCD aqueous solution in step (1) and mix them, wherein the mass ratio of the PEDOT / PSS dispersed solution to the MPBCD aqueous solution is 1:50.

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

[0062] The dry electrode film prepared in this embodiment has poor strength and is too sticky, but has a good sterilization effect, which means that the more MPBCD, the better the sterilization effect, but other properties are relatively weak, and the use effect is not good.

[0063] Comparative Example 1

[0064] Pure PEDOT / PSS solution is used to prepare dry electrode films, but this method is basically unable to prepare dry electrode films.

[0065] Test Example 1

[0066] The conformality and adhesion of the PPM film were tested on normal skin, sweaty skin, hairy skin, hairy sweaty skin, and finger joint skin, and the adhesion was very good. Figure 2 As shown, the adhesion of the dry electrode film attached to these skins was tested. Even the adhesion on sweaty skin reached 0.6N / cm. The adhesion on the finger joints was the largest, and the conformal properties were very good.

[0067] Test Example 2

[0068] The used dry electrode film is regenerated, and the broken dry electrode film of the same size is soaked, regenerated, precipitated, and placed in a mold to make a new dry electrode of the same size. Figure 4 As described above, the EMG and EOG signals generated after remodeling were compared with those generated before remodeling. The signals before and after basically overlapped, and their signal intensities could not be distinguished, and the difference was very small.

[0069] Test Example 3

[0070] The products prepared in Examples 1-3 and the blank sample of Comparative Example 1 were tested for antibacterial properties. Escherichia coli, Staphylococcus aureus clones and Gram-positive bacteria in Table 1 were then contacted with dry electrode films with different MPBCD contents, and the distance between the bacterial colony and the material on the LB plate was checked to determine the bactericidal ability. I represents a blank sample, i.e., pure PEDOT / PSS (dry electrode film prepared in Comparative Example 1); II is PEDOT / PSS:MPBCD=1:10 (mass ratio, dry electrode film prepared in Example 1); III is PEDOT / PSS:MPBCD=1:20 (mass ratio, dry electrode film prepared in Example 2); IV is PEDOT / PSS:MPBCD=1:30 (mass ratio, dry electrode film prepared in Example 3).

[0071] Table 1 Comparison of the bactericidal ability of products with different MPBCD ratios against different bacterial groups (radius of the sterilization circle)

[0072]

[0073] It can be seen from Table 1 that the pure PEDOT / PSS film has basically no antibacterial properties, and the dry electrode film prepared with PEDOT / PSS:MPBCD=1:30 has the largest antibacterial range, that is, the strongest antibacterial property.

[0074] The dry electrode film prepared in Example 3 was used on the skin in a cycle and then reshaped and then recycled. The antibacterial ability test of the dry electrode after different cycle times is shown in Table 2.

[0075] Table 2 shows the antibacterial (Gram-positive bacteria) ability of dry electrodes at different cycle times

[0076]

[0077] 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 the antibacterial performance is still very strong after being cycled 100 times and 500 times after being reshaped.

[0078] The dry electrode film prepared in Example 3 was adhered to different skin types: normal skin, sweating skin, hairy skin, hairy sweating skin, finger joints, etc. Figure 2 As shown, even on hairy, sweaty skin, the adhesion reaches nearly 0.6 N / cm.

[0079] like Figure 3As shown, it is a comparison diagram of the electromyographic potential signal (EMG) on the skin of the dry electrode film prepared in Example 3 during normal use and after remodeling. The signal is still very strong after remodeling.

[0080] like Figure 4 As shown, it is a comparison diagram of the potential signal (EOG) around the eye of the dry electrode film prepared in Example 3 during normal use and after remodeling. The signal is also very strong after remodeling.

[0081] The meanings of the English abbreviations in this application

[0082] EDOT: 3,4-ethylenedioxythiophene;

[0083] PEDOT: polymer of EDOT, poly 3,4-ethylenedioxythiophene;

[0084] MPBCD: chlorhexidine diacetate;

[0085] PSS: sodium polystyrene sulfonate;

[0086] PPM: dry electrode film assembled from PEDPT / PSS and MPBCD;

[0087] EMG: electromyographic signal;

[0088] EOG: electrooculogram.

[0089] Of course, 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 technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A reusable antibacterial dry electrode, characterized in that: At room temperature, PEDOT / PSS and MPBCD are quickly assembled under solvent-free conditions to form a flexible, adhesive-adjustable, reshapeable conductive dry electrode film, which is then connected with wires to form a dry electrode circuit; the mass ratio of PEDOT / PSS solution to MPBCD solution is 1:10-50.

2. A method for assembling a reusable antibacterial dry electrode, characterized in that: The specific steps include: (1) Dilute MPBCD into an aqueous solution with a concentration of 100 mM; (2) PSS was dissolved in deionized water, stirred evenly and divided into two equal parts. EDOT was added to one PSS aqueous solution and mixed. An oxidant was added to the other PSS solution and mixed. The two solutions were then mixed and added to a three-necked flask. Nitrogen was introduced at the same time and mechanically stirred at room temperature. 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 to obtain a product in powder form, and finally the powder product was dispersed in deionized water to obtain a stable PEDOT / PSS dispersion solution; (3) taking the PEDOT / PSS dispersed solution prepared in step (2), adding it to the MPBCD aqueous solution prepared in step (1), mixing, and then centrifuging to obtain a precipitate; (4) Place the removed precipitate into a mold to obtain a dry electrode.

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

4. The method for assembling a reusable antibacterial dry electrode according to claim 3, characterized in that: In the step (2), in one portion of the PSS aqueous solution, the volume ratio of PSS to the added EDOT is 1 to 10:

1.

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

6. The method for assembling a reusable antibacterial dry electrode according to claim 2, characterized in that: In the step (2), the two solutions are mixed and added into a three-necked flask, and the mechanical stirring time is 20 to 30 hours.

7. The method for assembling a reusable antibacterial dry electrode according to claim 2, characterized in that: In the step (2), the mass ratio of the obtained PEDOT to PSS is 1:2.5-5.

8. The method for assembling a reusable antibacterial dry electrode according to claim 2, characterized in that: In the step (3), the mass ratio of the PEDOT / PSS dispersed solution to the MPBCD aqueous solution is 1:10-50.

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