Conductive hydrogel material and preparation method and application thereof

Abstract

The application discloses a conductive hydrogel material and a preparation method and application thereof. The preparation method comprises the following steps: subjecting a first high polymer compound and a second high polymer compound to a Michael addition reaction and a cross-linking reaction to prepare a hydrogel precursor; and subjecting the hydrogel precursor to compression mixing with a conductive carbon-based material in a mold, standing, demolding, and preparing the conductive hydrogel material. The preparation method mixes the conductive carbon-based material with the hydrogel precursor in the mold, improves the conductivity of the carbon-based conductive hydrogel prepared by a traditional method, and makes the carbon-based conductive hydrogel have a wider application space in the field of biosensing. Meanwhile, the conductive hydrogel material prepared by the application has good mechanical properties and certain adhesion, the hydrogel components are safe and have good biocompatibility, the conductive hydrogel material can better simulate a cell growth environment as a biological scaffold material, and the cell growth can be regulated through external stimulation; and the material has good mechanical properties and good pressure sensitivity, and is suitable for being used as a flexible biosensing electrode material.

Description

Technical Field

[0001] This invention relates to a hydrogel material, and more particularly to a conductive hydrogel material, its preparation method, and its application, belonging to the field of nanomaterials technology. Background Technology

[0002] Hydrogels are flexible materials with a three-dimensional network structure, formed by the cross-linking of polymers containing hydrophilic groups through intermolecular covalent bonds and hydrogen bonds, using water as a medium. Carbon-based materials, due to their high conductivity and large specific surface area, have become ideal conductive fillers for conductive hydrogels. Hydrogel scaffold materials can mimic natural tissues in structure and function, providing cell adhesion sites and three-dimensional growth space, facilitating intercellular communication and the transport of nutrients and metabolites. Simultaneously, hydrogel scaffold materials possess good biocompatibility, highly mimicking the in vivo microenvironment, maintaining cell phenotype, and promoting the formation of neural tissue. Furthermore, flexible wearable sensors fabricated using hydrogel materials offer greater flexibility, extensibility, and smaller size compared to traditional rigid electronic sensors, capable of converting pressure and deformation into recordable electronic signals. Conductive hydrogels combine the properties of both conductive materials and hydrogels, making them applicable in tissue engineering materials, biosensing, and other fields.

[0003] CN113308148A discloses a method for preparing a conductive hydrogel ink, wherein the conductive hydrogel components include polyvinyl alcohol, carbon nanotubes, sodium carboxymethyl cellulose, etc. The mechanical strength of the hydrogel is improved by a cyclic freeze-thaw process. CN110746615B discloses a method for preparing a pH-responsive high-strength conductive hydrogel and its applications. The hydrogel prepared by this method has high strength and can be safely used as a drug carrier. However, the conductive hydrogels prepared by the above methods all have low conductivity, which limits their applications to some extent. CN114349980A discloses a conductive hydrogel, its preparation method, and its applications. The conductive hydrogel is composed of sodium alginate, unsaturated monomers, and metal ions. The conductive hydrogel prepared by this invention has good conductivity, ductility, and high sensitivity, and can be used to prepare sensors. However, its gelation and curing time is long, and the presence of metal ions makes its biocompatibility poor, which limits its application in biosensing to some extent.

[0004] In summary, most current research focuses on crosslinking conductive polymers with other polymeric materials using physical or chemical methods to create conductive composite hydrogel scaffolds. While this gives the conductive composite scaffolds the unique properties of both biopolymers and conductive polymers, the drawbacks of conductive hydrogel scaffolds, such as low conductivity, simple structure, poor flexibility, and poor biocompatibility, are difficult to overcome to meet the needs of tissue engineering applications. Therefore, providing a conductive hydrogel material that combines high conductivity, good biocompatibility, and rich spatial structures is an urgent problem to be solved. Summary of the Invention

[0005] The main objective of this invention is to provide a conductive hydrogel material and its preparation method to overcome the shortcomings of the prior art.

[0006] Another object of the present invention is to provide applications of the conductive hydrogel material.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] This invention provides a conductive hydrogel material, which is made by Michael addition reaction and cross-linking reaction of a first polymer compound and a second polymer compound, followed by doping with a conductive carbon-based material.

[0009] In some embodiments, the first polymeric compound includes any one or a combination of two or more of collagen, hyaluronic acid, and gelatin, but is not limited thereto.

[0010] In some embodiments, the second polymeric compound includes any one or a combination of two of polyethylene glycol and polyvinyl alcohol, but is not limited thereto.

[0011] This invention also provides a method for preparing a conductive hydrogel material, comprising:

[0012] A hydrogel precursor was prepared by subjecting the first polymer compound and the second polymer compound to Michael addition and cross-linking reactions.

[0013] Conductive carbon-based materials and hydrogel precursors are compressed and mixed in a mold, left to stand, and then demolded to obtain conductive hydrogel materials.

[0014] This invention also provides a conductive hydrogel material prepared by the aforementioned method.

[0015] The embodiments of the present invention also provide applications of the aforementioned conductive hydrogel materials in fields such as biomaterials, biosensors, or wearable devices.

[0016] Accordingly, embodiments of the present invention also provide a conductive hydrogel electrode material, which includes the aforementioned conductive hydrogel material.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The method for preparing conductive hydrogel materials provided by this invention involves mixing conductive carbon-based materials with a hydrogel precursor solution in a mold, which improves the conductivity of carbon-based conductive hydrogels prepared by traditional methods, thus expanding their application scope in the field of biosensing. Simultaneously, the conductive hydrogel material prepared by this invention exhibits good mechanical properties and certain adhesion, and its hydrogel composition is safe and biocompatible, making it a better bioscaffold material for mimicking the cell growth environment and enabling the regulation of cell growth through external stimuli. Furthermore, the conductive hydrogel material prepared by this invention has good mechanical properties and high pressure sensitivity, making it suitable as a flexible biosensing electrode material. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1a This is the NMR spectrum of HA in Embodiment 1 of the present invention;

[0021] Figure 1b This is the NMR spectrum of thiolated hyaluronic acid (HA-SH-DPA) in Example 1 of this invention;

[0022] Figure 1c This is the NMR spectrum of the double-bond modified polyvinyl alcohol (PVA-AC) in Example 1 of this invention;

[0023] Figure 2 This is a morphological diagram of the conductive hydrogel in a typical embodiment of the present invention;

[0024] Figure 3 This is a morphological diagram of the ring-shaped conductive hydrogel prepared in Example 1 of the present invention;

[0025] Figure 4a This is a scanning electron microscope image of the conductive hydrogel material prepared in Example 1 of the present invention;

[0026] Figure 4b This is a scanning electron microscope image of carbon nanotubes in the conductive hydrogel material prepared in Example 1 of the present invention;

[0027] Figure 5 This is a rheological test diagram of the conductive hydrogel material prepared in Example 1 of the present invention;

[0028] Figure 6This is a compression test diagram of the conductive hydrogel material prepared in Example 1 of the present invention;

[0029] Figure 7 This is a swelling test diagram of the conductive hydrogel material prepared in Example 1 of the present invention;

[0030] Figure 8 This is a test diagram of the induced electromotive force generated in Embodiment 1 of the present invention;

[0031] Figure 9 This is a biocompatibility test diagram of the conductive hydrogel material prepared in Example 1 of the present invention;

[0032] Figure 10 This is a diagram showing the proliferation morphology of neural stem cells in conductive hydrogel material in Embodiment 1 of the present invention;

[0033] Figure 11 This is a biosensing attempt of the conductive hydrogel material prepared in Example 1 of the present invention. Detailed Implementation

[0034] In view of the deficiencies of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles. However, it should be understood that within the scope of this invention, the above-mentioned technical features of this invention and the technical features specifically described below (exemplary embodiments) can be combined with each other to constitute new or preferred technical solutions. Due to space limitations, they will not be described in detail here.

[0035] As one aspect of the technical solution of the present invention, a conductive hydrogel material is involved, which is formed by cross-linking two polymers. Specifically, it is made by Michael addition reaction and cross-linking reaction of a first polymer compound and a second polymer compound, followed by doping with a conductive carbon-based material.

[0036] In some embodiments, the first polymer compound and the second polymer compound are chemically modified according to the desired structure of the natural polymer.

[0037] Furthermore, considering the good biocompatibility of natural polymers, natural polymers are preferred for modification.

[0038] In some preferred embodiments, the first polymeric compound may include any one or a combination of two or more of collagen, hyaluronic acid, gelatin, etc., but is not limited thereto. The first polymeric compound is a modified polymeric compound derivative. The hydrogel's adhesiveness arises from modification of the polymeric compound with at least one of dopamine (DOPA), tannic acid (DA), etc.

[0039] In some preferred embodiments, the second polymeric compound includes any one or a combination of two of polyethylene glycol (PEG), polyvinyl alcohol (PVA), etc., but is not limited thereto. The second polymeric compound is a modified polymeric compound derivative, and the hydrogel adhesiveness originates from modification of the polymeric compound with at least one of acrylic acid, methacrylic acid, butenoic acid, etc.

[0040] In some more preferred embodiments, considering that mussel-like polydopamine and its derivatives contain abundant catechol and o-quinone groups, they exhibit strong adhesion to various substrate materials. This is mainly because phenolic and quinone chemical groups interconvert through semiquinone groups, thereby achieving a combination of multiple chemical reactions, endowing PDA with strong adhesion and ease of secondary functionalization of substrate materials. Dopamine modification is preferred, to prepare dopamine-modified thiolized hyaluronic acid.

[0041] In some more preferred embodiments, considering the polymer's water retention and the presence of functional groups capable of click chemistry reactions such as Michael addition reactions, which enable chemical crosslinking, polyvinyl alcohol is preferably modified to obtain polyvinyl alcohol with C-C double bonds.

[0042] In some preferred embodiments, the conductive carbon-based material includes any one or a combination of two or more of carbon nanotubes, graphene oxide, graphene, and nanographene, but is not limited thereto.

[0043] Furthermore, the carbon nanotube is preferably a multi-walled carbon nanotube, the outer diameter of the multi-walled carbon nanotube is preferably less than 2 nm, and the length of the multi-walled carbon nanotube is preferably 5 to 30 μm.

[0044] In some preferred embodiments, the conductive carbon-based material content in the conductive hydrogel material is 10–40 wt%.

[0045] In some preferred embodiments, the conductivity of the conductive hydrogel material reaches 5 to 20 S / m.

[0046] Furthermore, the conductive hydrogel material prepared by this invention also possesses a certain degree of adhesion. The source of the hydrogel's adhesion is the modification of the polymer compound with at least one of the following: dopamine (DOPA), dopamine (DA), tannic acid (TA), etc.

[0047] Another aspect of the present invention provides a method for preparing a conductive hydrogel material, comprising:

[0048] A hydrogel precursor was prepared by subjecting the first polymer compound and the second polymer compound to Michael addition and cross-linking reactions.

[0049] Conductive carbon-based materials and hydrogel precursors are compressed and mixed in a mold, left to stand, and then demolded to obtain conductive hydrogel materials.

[0050] As one of the preferred embodiments, the preparation method includes:

[0051] A first solution containing a first polymer compound and a second solution containing a second polymer compound are mixed, and the first polymer compound and the second polymer compound undergo Michael addition reaction and cross-linking reaction to obtain a hydrogel precursor solution.

[0052] The conductive carbon-based material is compressed in a mold, then mixed with a hydrogel precursor solution, left to stand, and then demolded to obtain the conductive hydrogel material.

[0053] Furthermore, the reactions in this invention include a combination of Michael addition reactions and crosslinking reactions.

[0054] The types of the first polymer compound, the second polymer compound, and the conductive carbon-based material are as specified above and will not be repeated here.

[0055] As one of the preferred options, the mass ratio of the first polymer compound to the second polymer compound is 1:1 to 3:1.

[0056] Furthermore, a solution of one polymeric compound, such as collagen, hyaluronic acid, or gelatin, and a solution of another polymeric compound, such as a polyethylene glycol (PEG) derivative or a polyvinyl alcohol (PVA) derivative, are mixed in a ratio of 1:1 to 3:1, preferably at 2.5 wt% and 2 wt%, respectively, and the mixture undergoes a Michael addition reaction between -SH and the double bond groups in the carboxyl group, as well as a cross-linking reaction between -SH groups.

[0057] Furthermore, a polymeric compound derivative includes at least one modification thereof, such as dopamine (DOPA), tannic acid (TA).

[0058] As one preferred embodiment, the pH value of the first solution or the second solution is 7.7 to 8.0. That is, the pH values ​​of the first solution containing the first polymer compound and the second solution containing the second polymer compound are each independently 7.7 to 8.0.

[0059] As one of the preferred embodiments, the preparation method includes: mixing polymer solutions with pH values ​​of 7.7 to 8.0 independently, carrying out Michael addition and cross-linking reactions, and adding the mixture into a mold containing a conductive carbon-based material to obtain the conductive hydrogel material.

[0060] More specifically, the preparation method may include: pressing the conductive carbon-based material into a mold until it is relatively compact; slowly adding a mixed solution until the solution has completely penetrated and reached saturation; stopping the addition; allowing it to stand; demolding; and obtaining the conductive hydrogel material.

[0061] As one of the preferred options, the settling time is 5 to 15 minutes.

[0062] In some more specific embodiments, the specific preparation steps of the conductive hydrogel material of the present invention are as follows:

[0063] Preparation of the hydrogel precursor solution: HA was dissolved in distilled water at a concentration of 1% (w / v). 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and NHS (N-hydroxysuccinimide) were added to the HA solution in an equimolar ratio, and the mixture was stirred for 30 minutes at pH 5.0. Dopamine hydrochloride was then added to the solution in an equimolar ratio with HA, and the mixture was stirred overnight at room temperature with 1M hydrochloric acid, maintaining a pH of 5.0. Deionized water was added, and 3,3'-dithiodipropionylhydrazine was added while stirring. The pH was adjusted to 4.75 with hydrochloric acid solution. Then, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) was added, and the pH was adjusted to 4.75 with 1M hydrochloric acid solution. Dithiothreitol (DTT) was added, and the reaction was carried out at room temperature with stirring for half an hour. Sodium hydroxide solution was added to adjust the pH to 8.5, and the reaction was stirred for 24 hours. The reaction solution was collected, adjusted to pH 3.5, and transferred to a dialysis bag. After dialysis, it was freeze-dried to obtain thiolized hyaluronic acid (denoted as: HA-SH-DPA).

[0064] Polyvinyl alcohol (PVA) was dissolved in dimethyl sulfoxide (DMSO) at a concentration of 5% (w / v). Acrylic acid (AA) was added at a ratio of 1:1.5, along with catalysts di-tert-butyl dicarbonate (Boc)₂O and 4-dimethylaminopyridine (DMAP). The reaction was carried out at room temperature for 24 hours. After dialysis, the PVA with double bonds was obtained by freeze-drying (denoted as PVA-AC).

[0065] HA-SH-DPA and PVA-AC were dissolved in phosphate buffer (PBS) solution, and the pH of each solution was adjusted to 7.7-8.0. The HA-SH-DPA solution and PVA-AC were mixed at a ratio of 1:1 to 3:1, preferably 2.5 wt% and 2 wt%, respectively. The mixture was subjected to Michael addition reaction between -SH and the double bond groups in the carboxyl group, as well as cross-linking reaction between -SH groups.

[0066] Two polymer solutions with independent pH values ​​of 7.7–8.0 were mixed to carry out Michael addition and cross-linking reactions.

[0067] 10–40 wt% (preferably 20 wt%) of carbon nanotubes are placed in a mold and pressed firmly. The mixed solution is then slowly added to the compacted carbon nanotubes. As the solution slowly penetrates, it is stopped once the solution has completely penetrated the carbon nanotubes and reached saturation. After standing for 5–15 minutes, the material is demolded to obtain a conductive hydrogel material doped with carbon nanotubes.

[0068] In summary, the preparation method of the present invention, which compresses conductive carbon-based materials and mixes them with hydrogel precursor solutions in a mold, improves the conductivity of carbon-based conductive hydrogels prepared by traditional methods, thus enabling them to have a wider range of applications.

[0069] Specifically, another aspect of the present invention provides a conductive hydrogel material prepared by the aforementioned preparation method.

[0070] Specifically, another aspect of this invention provides the application of the aforementioned conductive hydrogel material in biomaterials, including but not limited to stem cell culture scaffolds, where the proliferation and differentiation of stem cells are regulated within the conductive hydrogel scaffold material. The conductive hydrogel material provided by this invention is safe in composition and has good biocompatibility. As a biological scaffold material, it better simulates the cell growth environment and can regulate cell growth through external stimuli.

[0071] The biomaterials include flexible biosensing electrode materials.

[0072] Specifically, the application of the conductive hydrogel material as a scaffold in biomaterials includes:

[0073] The two polymer solutions described above, each with a pH value of 7.7-8.0 (preferably 7.8), were mixed with neural stem cells and added to compacted carbon nanotubes. As the solutions slowly infiltrated, they crosslinked in situ to form a hydrogel / stem cell culture scaffold. Cell proliferation medium was added, and the scaffold was cultured at 37 degrees Celsius and 5% CO2 for 7 days. Cell morphology was observed. After 7 days of culture, the cells were immunofluorescence stained and observed and photographed using a laser confocal microscope. The biocompatibility of the material was detected by cell viability / death analysis.

[0074] Specifically, another aspect of the present invention provides the application of the aforementioned conductive hydrogel material in the field of bio-flexible sensing or wearable devices.

[0075] Specifically, the conductive hydrogel material prepared by this invention has good mechanical properties and good pressure sensitivity, making it suitable as a flexible biosensing electrode material.

[0076] Furthermore, the applications of the conductive hydrogel scaffold in biosensing include:

[0077] The conductive hydrogel material is attached to the part of the human body that needs to be monitored (such as finger joints, wrists, elbows, knees, etc.), preferably the wrist. Then the conductive hydrogel is connected to an electrochemical workstation, and the electrochemical workstation program is set to the working mode of it, with a voltage of 0.1-2V, preferably 0.2V. The real-time current is recorded in the discharge state, and the real-time resistance value of the flexible sensor is obtained by calculation.

[0078] Performance testing:

[0079] Conductivity test: The conductivity of the conductive hydrogel was tested using a four-probe tester. Furthermore, the conductivity of the carbon nanotube hydrogel reached 5-20 S / m.

[0080] Mechanical property testing: The storage modulus (G′) and loss modulus (G″) under different parameter settings were measured using a rotational rheometer to study the viscous, elastic, and other rheological properties of the hydrogel scaffold. Hydrogel samples with a diameter of 1 cm and a height of 8 mm were prepared. The compressive properties of the hydrogel scaffold material were tested using a universal joint analyzer with a compression rate of 1 mm / min. The change in compressive stress from 0% to 60% of the compressive strain of the carbon nanotube hydrogel was measured. The stress-strain curves of the hydrogel scaffold deformation were obtained.

[0081] Swelling rate test: The prepared conductive hydrogel scaffold was washed with PBS. The hydrogel sample was then washed and dehydrated sequentially with 0%, 25%, 50%, 75%, and 100% ethanol solutions. After drying, the weight of the hydrogel scaffold was recorded. The dried hydrogel scaffold was then re-immersed in PBS solution, and the weight of the hydrogel scaffold at different time points was recorded until the hydrogel scaffold reached swelling equilibrium. The swelling rate was then calculated.

[0082] Detection of induced current in conductive ring-shaped hydrogels: A primary coil carrying an electrical signal radio-stimulates a three-dimensional ring-shaped cell scaffold, thereby modulating the cells. Furthermore, the electrical signal is a sinusoidal alternating current signal with a frequency of 25 kHz and a current of 2 A.

[0083] Another aspect of the present invention provides a conductive hydrogel electrode material, which includes the aforementioned conductive hydrogel material.

[0084] In summary, this invention improves the conductivity of carbon-based conductive hydrogels prepared by compressing and mixing conductive carbon-based materials with hydrogel precursor solutions in a mold. Traditional methods involve mixing conductive carbon-based materials with hydrogel precursor solutions and then injecting the mixture into a mold. This invention increases the number of interconnected nodes and pathways in the carbon-based conductive materials, resulting in higher conductivity in the prepared conductive hydrogel material. Chemical modification of the polymer compounds with dopamine (DA) and other compounds further enhances the adhesion of the conductive hydrogel material.

[0085] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The implementation conditions used in the following embodiments can be further adjusted according to actual needs, and the implementation conditions not specified are generally the conditions in conventional experiments.

[0086] Example 1

[0087] Weigh 200 mg of hyaluronic acid and dissolve it in 10 ml of deionized water. Add 77 mg of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and 57 mg of NHS (N-hydroxysuccinimide) to the HA solution and stir for 30 minutes at pH 5.0. Add 100 mg of dopamine hydrochloride to the solution and stir overnight at room temperature with 1 M hydrochloric acid, maintaining the pH at 5.0. Add 10 ml of deionized water, and while stirring, add 250 mg of 3,3'-dithiodipropionylhydrazine. Adjust the pH to 4.75 with 1 M hydrochloric acid solution. Then add 210 mg of 1-ethyl-3-I3-dimethylaminopropyl-carbodiimide (IEDC), adjust the pH to 4.75 with 1 M hydrochloric acid solution, and add 1.0 g of dithiothreitol (DTT). React at room temperature with stirring for half an hour. Add 1 mol / L sodium hydroxide solution to adjust the pH to 8.5, and stir for 24 hours. Collect the reaction solution, adjust the pH to 3.5, and transfer it to an 8000-12000 kDa dialysis bag. Dialyze for three days in hydrochloric acid solution containing 100 mM sodium chloride at pH 3.5, and then for two days in dilute hydrochloric acid solution at pH 3.5. After dialysis, freeze-dry to obtain thiolated hyaluronic acid (denoted as HA-SH-DPA). The NMR spectrum of HA is shown below. Figure 1a As shown, the NMR spectrum of HA-SH-DPA is as follows: Figure 1b As shown, the preparation process is as follows:

[0088]

[0089] 1.0 g of polyvinyl alcohol (PVA) was dissolved in 20 ml of dimethyl sulfoxide (DMSO). 2.4 g of acrylic acid (AA) was added, and while stirring, 0.6 g of di-tert-butyl dicarbonate (Boc)₂O and 0.25 g of 4-dimethylaminopyridine (DMAP) were added. The reaction mixture was allowed to react at room temperature for 24 h. The reaction solution was collected, adjusted to pH 5, and transferred to a 30000-5000 kDa dialysis bag. Dialysis was performed in a solution at pH 5 for three days. After dialysis, the PVA with double bonds was obtained by freeze-drying (denoted as PVA-AC). The NMR spectrum of PVA-AC is shown below. Figure 1c As shown, the preparation process is as follows:

[0090]

[0091] HA-SH-DPA and PVA-AC were dissolved in phosphate buffer solution, with HA-SH-DPA content of 2.5 wt% and PVA-AC content of 2.0 wt%, respectively. After mixing, a hydrogel precursor solution was obtained.

[0092] Two polymer solutions, each with a pH of 7.8, were mixed to carry out Michael addition and cross-linking reactions.

[0093] 20 wt% of multi-walled carbon nanotubes with a length of approximately 20 μm and an outer diameter of 1 nm were placed in a polytetrafluoroethylene mold (preferably a ring mold as shown in the figure) and pressed firmly. The mixed solution was then slowly added to the compacted carbon nanotubes. As the solution slowly penetrated, it was stopped once the solution had completely penetrated into the carbon nanotubes and reached saturation. After standing for 8 minutes, a conductive hydrogel material doped with carbon nanotubes was obtained.

[0094] The morphology of the conductive hydrogel material obtained in this embodiment is as follows: Figure 3 As shown.

[0095] The scanning electron microscope image of the conductive hydrogel material obtained in this embodiment is as follows: Figure 4a As shown, the scanning electron microscope image of carbon nanotubes in the conductive hydrogel material is as follows: Figure 4b As shown.

[0096] The inventors in this case also conducted the following performance tests on the prepared conductive hydrogel material:

[0097] Conductivity test: The conductivity of the conductive hydrogel was tested using a four-probe tester. Furthermore, the conductivity of the carbon nanotube hydrogel material reached 5-20 S / m.

[0098] Mechanical property testing: Rheological testing (see...) Figure 5 The prepared conductive hydrogel material has an elastic modulus of 5.5 kPa, exhibiting good shear resistance and linear viscoelasticity. Compression performance test results are shown below. Figure 6 This indicates that carbon nanotube hydrogels have excellent compressive strength, and can still maintain structural integrity when the compressive strain reaches 60%.

[0099] Swelling rate test: The swelling rate test results are as follows Figure 7 As time progresses, the sample reaches swelling equilibrium in about 30 hours, with an equilibrium swelling rate of 6-10, indicating that the sample has good water absorption and swelling properties.

[0100] Detection of induced current in conductive ring-shaped hydrogels: A primary coil carrying an electrical signal (a sinusoidal alternating current with a frequency of 25 kHz and a current of 2 A) radio-stimulates a three-dimensional ring-shaped cell scaffold, generating an induced electromotive force of 0.20-0.30 V in the secondary coil, resulting in an induced current of 140-160 μA. The structure is as follows. Figure 8 As shown, this indicates that the conductive hydrogel material has good electrical conductivity and is suitable as a scaffold material for regulating cell proliferation and differentiation.

[0101] Applications in biomaterials: such as Figure 9 As shown, the conductive hydrogel scaffold material prepared in this embodiment is conducive to stem cell growth. Neural stem cells grow in a spherical morphology within the scaffold, exhibiting high cell viability. The proliferation morphology of neural stem cells in the conductive hydrogel material is illustrated in the figure below. Figure 10 As shown, the conductive hydrogel scaffold material has good biocompatibility.

[0102] Therefore, the conductive hydrogel scaffold material prepared in this embodiment has high electrical conductivity, mechanical strength and viscoelasticity, and good biocompatibility.

[0103] Applications in biosensing: such as Figure 11 As shown, the above-mentioned conductive hydrogel material is attached to the human wrist with conductive tape. As the wrist moves regularly, the resistance value of the conductive hydrogel material changes regularly, realizing biosensing and achieving the purpose of monitoring human movement.

[0104] Example 2

[0105] The preparation method used in this embodiment is the same as in Example 1, except that the solid content of HA-SH-DPA and PVA-AC in the hydrogel precursor solution is 3wt%.

[0106] Example 3

[0107] The preparation method used in this embodiment is the same as in Example 1, except that the solid contents of HA-SH-DPA and PVA-AC in the hydrogel precursor solution are 4.5 wt% and 1.5 wt%, respectively.

[0108] Example 4

[0109] The preparation method used in this embodiment is the same as that in Example 1, except that the pH value of the first solution and the second solution is 7.7, and they are allowed to stand for 15 minutes to form a gel.

[0110] Example 5

[0111] The preparation method used in this embodiment is the same as that in Example 1, except that the pH value of the first solution or the second solution is 7.8 and it is allowed to stand for 8 minutes to form a gel.

[0112] Example 6

[0113] The preparation method used in this embodiment is the same as that in Embodiment 1, except that the pH value of the first solution or the second solution is 8.0, and it is allowed to stand for 5 minutes to form a gel.

[0114] Example 7

[0115] The preparation method used in this embodiment is the same as in Example 1, except that the carbon nanotube content is 10 wt%.

[0116] Example 8

[0117] The preparation method used in this embodiment is the same as in Example 1, except that the carbon nanotube content is 40 wt%.

[0118] Example 9

[0119] The preparation method used in this embodiment is the same as that in Example 1, except that: 20wt% of multi-walled carbon nanotubes with a length of about 20μm and an outer diameter of 1nm are directly mixed with the hydrogel precursor solution and then injected into a mold and allowed to stand to form a gel.

[0120] Example 10

[0121] The preparation method used in this embodiment is the same as in Example 1, except that the two polymer mixed solutions are slowly added to the compacted graphene.

[0122] Example 11

[0123] The preparation method used in this embodiment is the same as in Example 1, except that the two polymer mixed solutions are slowly added to the compacted graphene oxide.

[0124] By comparing the mechanical properties of the conductive hydrogel scaffold materials in Examples 1, 2, and 3, it can be concluded that the conductive hydrogel material prepared in Example 1 has the best mechanical properties.

[0125] By comparing the biocompatibility of the conductive hydrogel scaffold materials in Examples 1, 7, and 8, it can be concluded that the conductive hydrogel material prepared in Example 1 has the best biocompatibility.

[0126] By comparing the conductivity of the conductive hydrogel scaffold materials in Examples 1 and 9, it can be seen that the conductivity of the conductive hydrogel material prepared by direct mixing in Example 9 is 0.5-1.9 S / m, which is much lower than the conductivity of the conductive hydrogel material prepared in Example 1.

[0127] By comparing the conductivity of the conductive hydrogel scaffold materials in Examples 1, 10, and 11, it can be seen that the conductivity of the conductive hydrogel materials prepared in Examples 10 and 11 is 0.2-4.5 S / m, which is much lower than the conductivity of the conductive hydrogel material prepared in Example 1.

[0128] In summary, the conductive hydrogel scaffold material prepared in Example 1 exhibits the best overall performance. In this example, replacing hyaluronic acid with collagen or gelatin yielded similar experimental results, as did replacing modified dopamine with dopa or tannic acid. Furthermore, replacing polyvinyl alcohol with polyethylene glycol and modifying it with acrylic acid, methacrylic acid, or methacrylic acid also resulted in similar experimental results.

[0129] The morphology of the conductive hydrogel materials prepared in other embodiments of the present invention can be referred to Figure 2 and Figure 3 As shown.

[0130] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0131] It should be understood that the examples described above are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be used to limit the scope of protection of the present invention. All equivalent transformations or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a conductive hydrogel material, characterized in that, include: A first solution containing a first polymer compound and a second solution containing a second polymer compound are mixed, and the first polymer compound and the second polymer compound are subjected to Michael addition reaction and cross-linking reaction to obtain a hydrogel precursor solution. The first polymer compound is any one or a combination of two or more of collagen, hyaluronic acid and gelatin modified with at least one of dopamine and tannic acid. The second polymer compound is any one or a combination of two of polyethylene glycol and polyvinyl alcohol modified with at least one of acrylic acid, methacrylic acid and butenoic acid. The conductive carbon-based material is compacted in a mold, then mixed with a hydrogel precursor solution, allowed to stand, and then demolded to obtain a conductive hydrogel material. The conductive carbon-based material is carbon nanotubes.

2. The preparation method according to claim 1, characterized in that: The carbon nanotubes are multi-walled carbon nanotubes with an outer diameter of less than 2 nm and a length of 5 to 30 μm.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the first polymer compound to the second polymer compound is 1:1 to 3:

1.

4. The preparation method according to claim 1, characterized in that: The pH value of the first or second solution is 7.7~8.

0.

5. The preparation method according to claim 1, characterized in that: The settling time is 5-15 minutes.

6. A conductive hydrogel material prepared by any one of claims 1-5.

7. The conductive hydrogel material according to claim 6, characterized in that: The conductive hydrogel material contains 10-40 wt% conductive carbon-based material.

8. The conductive hydrogel material according to claim 6, characterized in that: The conductivity of the conductive hydrogel material is 5~20 S / m.

9. The application of the conductive hydrogel material according to any one of claims 6-8 in the fields of biomaterials, biosensing or wearable devices.

10. The application according to claim 9, characterized in that: The biomaterials include flexible biosensing electrode materials.

11. A conductive hydrogel electrode material, characterized in that, The conductive hydrogel material includes any one of claims 6-8.

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