A marine antifouling conductive hydrogel, its preparation method and application

Abstract

This invention relates to a marine antifouling conductive hydrogel, its preparation method, and its applications, belonging to the fields of multifunctional materials platforms for biomedical engineering and soft bio-integrated electronics technology. A method for preparing a marine antifouling conductive hydrogel includes dissolving zwitterionic monomers, N-hydroxysuccinimide acrylate, and tannic acid in a polyaniline:polystyrene sulfonic acid aqueous dispersion, adding a hydrophobic crosslinking agent, and magnetically stirring at room temperature to obtain a pregel solution; adding an initiator to the pregel solution, stirring until homogeneous, and then carrying out a polymerization reaction to obtain the marine antifouling conductive hydrogel. This invention constructs a hydrated and electron-permeable interpenetrating network structure through a one-step in-situ gelation method, integrating antifouling activity, anti-swelling ability, cross-substrate wet adhesion, and stable signal transmission, and further spanning a wide salinity window in seawater, making it widely applicable in intelligent marine bioelectronics.

Description

Technical Field

[0001] This invention relates to a marine antifouling conductive hydrogel, its preparation method, and its application, belonging to the fields of biomedical engineering multifunctional material platform and soft biointegrated electronics technology. Background Technology

[0002] Seawater presents a series of rigorous and highly coupled challenges to hydrogel bioelectronics. Biofouling induces rapid nonspecific adsorption and biofilm evolution, while high salinity accelerates osmotic imbalance and expansion, collectively disrupting the material's microstructure and electroosmosis. These intertwined effects lead to significant impedance drift and phase noise, ultimately compromising long-term signal reliability. Overcoming these intertwined failure modes is a prerequisite for achieving stable marine bioelectronics.

[0003] Hydrogels, with their tissue-like compliance, inherent biocompatibility due to high water content, and ion-electron coupling signal transduction properties, have become cornerstone materials for flexible bio-integrated electronic components. These properties enable a wide range of bioelectronic applications, including wearable health monitoring, implantable therapies, and soft robotics, where conformal contact and long-term signal fidelity are crucial. However, extending hydrogel-supported bioelectronics from traditional operating environments to marine environments is still far from sufficient, as existing marine antifouling coatings lack the capability to cope with extreme marine conditions.

[0004] Hydrogels suitable for marine applications need to simultaneously inhibit early adsorption and biofilm formation, maintain dimensional and interfacial stability in high-salinity environments, and maintain drift-resistant electron transport for low-noise biosignal acquisition. However, these functions are rarely achieved simultaneously in existing integrated systems. Therefore, there is an urgent need to develop a novel material that combines strong adhesion, resistance to marine biofouling and high-salinity osmotic swelling, and multifunctional synergy to provide a better solution for physiological signal acquisition in marine environments. Summary of the Invention

[0005] To address the aforementioned technical problems in existing technologies, this invention provides a marine antifouling conductive hydrogel, its preparation method, and its applications. This invention constructs a hydrated, electron-permeable interpenetrating network structure using a one-step in-situ gelation method, which not only simulates the colloidal properties of jellyfish but also endows the hydrogel with excellent comprehensive properties.

[0006] The hydrogels of this invention are inspired by the marine organism jellyfish. The soft, hydrated bodies of jellyfish maintain minimal biofouling and continuous signal transmission while withstanding constant exposure to high salinity and microbial colonization. Their mesoglea layer possesses a highly hydrated yet mechanically stable matrix, enabling anti-stick surfaces, localized deformation control, and continuous signal transmission. This natural combination of hydration locking and antifouling behavior with mechanical and electrical stability provides an inspiring biomimetic approach for the bioelectronic engineering design of hydrogels suitable for marine environments.

[0007] A method for preparing a marine antifouling conductive hydrogel includes the following steps: dissolving zwitterionic monomers, N-hydroxysuccinimide acrylate, and tannic acid in a polyaniline:polystyrene sulfonic acid aqueous dispersion, adding a hydrophobic crosslinking agent, and magnetically stirring at room temperature to obtain a pregel solution; adding an initiator to the pregel solution, stirring evenly, and then carrying out a polymerization reaction to obtain a marine antifouling conductive hydrogel.

[0008] This invention constructs a basic network for hydration locking and electron permeation by introducing zwitterionic monomers, hydrophobic crosslinking agents, and polyaniline:polystyrene sulfonic acid (PANI:PSS). Electron conduction replaces traditional ion transport, thereby overcoming the instability of conductivity caused by ion migration and concentration changes, resulting in a hydrogel with long-term stable high conductivity in seawater. Furthermore, tannic acid (TA) is introduced to construct a hydration-polyphenol synergistic composite network through physical entanglement. Tannic acid assembles into a polyphenol-hydration shell within the hydrogel network, which stabilizes interfacial water, reduces interfacial free energy, and endows the hydrogel with dual synergistic antifouling capabilities of repellency and scavenging. Simultaneously, N-hydroxysuccinimide acrylate (AA-NHS) is added as a suspended active ester portion. The AA-NHS active ester chain rapidly undergoes amidation / esterification reactions with -NH2 / -OH groups on the matrix or tissue surface to form covalent anchorage.

[0009] Preferably, the zwitterionic monomer is [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide.

[0010] Preferably, the hydrophobic crosslinking agent is ethylene glycol dimethacrylate.

[0011] Preferably, the initiator is ammonium persulfate.

[0012] In the method of the present invention, the mass ratio of the zwitterionic monomer, hydrophobic crosslinking agent, polyaniline:polystyrene sulfonic acid aqueous dispersion, N-hydroxysuccinimide acrylate, tannic acid, and initiator is 100 : 2~10 : 20~30 : 50~75 : 200~300 : 5~10.

[0013] Furthermore, the mass concentrations of both polyaniline and polystyrene sulfonic acid in the polyaniline:polystyrene sulfonic acid aqueous dispersion are 1~3 wt%.

[0014] Furthermore, under the above-mentioned ratio conditions, the resulting hydrogel exhibits an ideal hydration interlock ratio, which can enhance the interchain restriction and hydrogen bond network order through moderate cross-linking, convert some free water into more stable bound water, thereby reinforcing the stable hydration layer induced by zwitterionic monomers, while avoiding the weakening of the hydrogel's antifouling performance due to excessive hydrophobicity.

[0015] In the method described in this invention, after adding the initiator, it is preferable to stir rapidly at 600~1200 rpm until homogeneous.

[0016] In the method of the present invention, the polymerization reaction conditions are 70~90℃ for 0.5~2 h.

[0017] In the preparation method of the marine sewage-proof gel of the present invention, a one-pot thermally initiated free radical copolymerization reaction is adopted. In this process, the zwitterionic side groups of the zwitterionic monomers form a strongly bound hydration layer, while the introduction of the hydrophobic crosslinking agent bridges multiple polymer chains into a dense chemical crosslinking network, converting free water into confined water, thereby inhibiting the permeation and swelling of the hydrogel in seawater.

[0018] Another object of the present invention is to provide a marine antifouling conductive hydrogel prepared by the above method.

[0019] Furthermore, the surface pore size of the marine antifouling conductive hydrogel is 2~5 μm, and the internal pore size is 10~20 μm.

[0020] Furthermore, the marine antifouling conductive hydrogel has an electrical conductivity of 15~25 S / m, a wet adhesion strength of 10~60 kPa, a burst pressure ≥150 kPa, a Young's modulus of 300~900 kPa, a maximum tensile strain of 150%~220%, and a mechanical toughness of 80~180 kJ / m. 3 .

[0021] Another object of the present invention is to provide the application of the above-mentioned marine antifouling conductive hydrogel in the preparation of marine antifouling biosensor materials.

[0022] The beneficial effects of this invention are:

[0023] (1) This invention constructs a hydration-locked matrix formed by zwitterionic monomers and hydrophobic crosslinking agents through a "hydration-locked percolation" strategy, effectively converting free water into bound water, fundamentally inhibiting osmotic swelling in high-salt environments, and maintaining the dimensional stability and structural integrity of the hydrogel. Simultaneously, the introduction of tannic acid (TA) to form a polyphenol-hydration shell not only stabilizes the interfacial water to "repel" fouling organisms but also "kills" already attached organisms through metal chelation and chemical reactions, achieving a synergistic dual-effect antifouling effect. The hydrogel obtained by this invention can maintain a clean sensing interface and stable material properties in complex marine environments for a long time, achieving a unified approach to synergistic antifouling and anti-swelling, overcoming the rapid failure problem of traditional hydrogels caused by swelling and fouling, and effectively addressing the coupled challenges of high salinity and biofouling in seawater.

[0024] (2) This invention constructs a solid-state electron permeation network independent of mobile ions by introducing the PANI:PSS conductive polymer into the hydrogel network. This network is unaffected by fluctuations in external salt concentration and changes in hydrogel volume, endowing the hydrogel with a high and long-term stable conductivity of 22 S / m. Therefore, the hydrogel obtained by this invention, when used as an electrode, can achieve stable acquisition of weak physiological signals such as electromyography and electrocardiography in dynamic seawater environments with high signal-to-noise ratio and low drift, and has long-term high-fidelity signal transmission performance, providing a material basis for reliable marine bioelectronic monitoring.

[0025] (3) By optimizing the content of the hydrophobic crosslinking agent, this invention not only improves the anti-swelling performance of the hydrogel, but also significantly enhances its mechanical strength, toughness, and fatigue resistance. Simultaneously, by introducing AA-NHS active ester, the hydrogel can achieve firm anchoring on wet surfaces through covalent bonds. The hydrogel obtained by this invention can maintain stable and shape-preserving adhesion to substrates such as skin even under dynamic conditions such as human movement or seawater erosion, avoiding signal artifacts and acquisition failures caused by relative displacement or detachment at the interface, and exhibiting excellent mechanical and cross-substrate wet adhesion properties. Attached Figure Description

[0026] Figure 1 This is a functional schematic diagram of the marine antifouling conductive hydrogel (DTPE hydrogel) suitable for marine bioelectronics obtained in this invention.

[0027] Figure 2 The images show the scanning electron microscope (SEM) morphology of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1.

[0028] Figure 3 The diagram shows the pore size distribution of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1.

[0029] Figure 4The Fourier transform infrared spectra of the hydrogels obtained in Examples 1-5 and Comparative Example 1 are shown.

[0030] Figure 5 The graph shows the swelling rate of the hydrogels obtained in Examples 1-5 and Comparative Example 1 in seawater over time.

[0031] Figure 6 The figures show the mechanical toughness results of the hydrogels obtained in Examples 1-5 and Comparative Example 1.

[0032] Figure 7 The graph shows the Young's modulus results of the hydrogels obtained in Examples 1-5 and Comparative Example 1.

[0033] Figure 8 The stress-strain curves are for the hydrogels obtained in Examples 1-5 and Comparative Example 1.

[0034] Figure 9 The image shows the rapid wet adhesion test results of the DTPE hydrogel obtained in Example 1 to different material substrates.

[0035] Figure 10 The graph shows the rapid wet adhesion test results of the DTPE hydrogel obtained in Example 1 on different material substrates.

[0036] Figure 11 The image shows the rapid wet adhesion test results of the DTPE hydrogel obtained in Example 1 to different biological tissues.

[0037] Figure 12 The image shows the results of rapid adhesion tests of the DTPE hydrogel obtained in Example 1 to different biological tissues.

[0038] Figure 13 The images show the adhesion test results of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1 to pig skin after soaking for 7 days.

[0039] Figure 14 The images show the morphology of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1 after soaking in pig skin for 7 days.

[0040] Figure 15 The images show the adhesion test results of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1 in a simulated marine oscillation environment.

[0041] Figure 16 The burst pressure results of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1 after immersion in seawater are shown in the figure.

[0042] Figure 17 The graph shows the protein adsorption test results of the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2.

[0043] Figure 18 The graph shows the bacterial inhibition zone test results of the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2.

[0044] Figure 19 The OD values ​​of the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2 are... 600 Image showing the results of the change test (planktonic bacteria).

[0045] Figure 20 The graph shows the ATP bioluminescence test results of the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2.

[0046] Figure 21 The results of colony count (a) and fluorescence intensity (b) after co-culturing the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2 with bacteria for 5 days are shown.

[0047] Figure 22 The images are scanning electron microscope images of the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2 after co-culturing with bacteria for 5 days.

[0048] Figure 23 The graph shows the conductivity changes of the hydrogels obtained in Examples 1-5 and Comparative Example 1 under different salt concentrations.

[0049] Figure 24 The graph shows the relative resistance changes of the DTPE hydrogel obtained in Example 1 and the DTP hydrogel obtained in Comparative Example 1 under different salt concentrations and 150% strain.

[0050] Figure 25 The image shows a comparison of the contact impedance and signal-to-noise ratio (SNR) of the DTPE hydrogel obtained in Example 1.

[0051] Figure 26 This is a comparison of the electrocardiogram (ECG) signals of the DTPE hydrogel obtained in Example 1 and the commercial electrode.

[0052] Figure 27 This is a comparison of electromyography (EMG) signals between the DTPE hydrogel obtained in Example 1 and the commercial electrode. Detailed Implementation

[0053] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0054] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0055] Example 1

[0056] A method for preparing a marine antifouling conductive hydrogel includes the following steps:

[0057] (1) Preparation of pregel solution: 1.6 g of zwitterionic monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (DMAPS), 1 g of N-hydroxysuccinimide acrylate (AA-NHS), and 0.4 g of tannic acid (TA) were dissolved in 4 g of PANI:PSS aqueous dispersion, and hydrophobic crosslinking agent ethylene glycol dimethacrylate (EDMA) was added to make its concentration in the mixed solution 8 wt%. The mixture was magnetically stirred at room temperature to form a uniform pregel solution; wherein, the mass concentration of PANI and PSS in the PANI:PSS aqueous dispersion was 1.5 wt% each.

[0058] (2) Initiation of polymerization: Add 0.12 g of ammonium persulfate (APS) to the pregel solution as an initiator and stir rapidly at 800 rpm until homogeneous. Then, inject the liquid into the mold.

[0059] (3) Gelation and post-treatment: The mold was placed in an oven at 80°C and heated for 1 h to complete the polymerization reaction. After cooling to room temperature, it was taken out of the mold to obtain a hydrogel with an EDMA content of 8 wt%, which was denoted as DTPE hydrogel.

[0060] Example 2

[0061] The difference between this embodiment and embodiment 1 is that in step (1), the concentration of EDMA in the mixed solution is 2 wt%, and the rest of the operation is the same as in embodiment 1, so that a hydrogel with an EDMA content of 2 wt% is obtained.

[0062] Example 3

[0063] The difference between this embodiment and embodiment 1 is that in step (1), the concentration of EDMA in the mixed solution is 4 wt%, and the rest of the operation is the same as in embodiment 1, so that a hydrogel with an EDMA content of 4 wt% is obtained.

[0064] Example 4

[0065] The difference between this embodiment and embodiment 1 is that in step (1), the concentration of EDMA in the mixed solution is 6 wt%, and the rest of the operation is the same as in embodiment 1, so that a hydrogel with an EDMA content of 6 wt% is obtained.

[0066] Example 5

[0067] The difference between this embodiment and embodiment 1 is that in step (1), the concentration of EDMA in the mixed solution is 10 wt%, and the rest of the operation is the same as in embodiment 1, so that a hydrogel with an EDMA content of 10 wt% is obtained.

[0068] Comparative Example 1

[0069] The difference between this comparative example and Example 1 is that: in step (1), no hydrophobic crosslinking agent EDMA is added, and the rest of the operation is the same as in Example 1, and a hydrogel without hydrophobic crosslinking agent is obtained, which is denoted as DTP hydrogel.

[0070] Comparative Example 2

[0071] The difference between this comparative example and Example 1 is that tannic acid is not added in step (1), and the rest of the operation is the same as in Example 1, so that a hydrogel without tannic acid is obtained, which is denoted as DPE hydrogel.

[0072] The structures of the hydrogels obtained in Examples 1-5 and Comparative Example 1 were characterized, and the results are shown in the figure. Figures 2-4 After freeze-drying the hydrogel sample, the microscopic pore structure of its surface and cross-section was observed using scanning electron microscopy (SEM). Figure 2 and Figure 3 As shown, the hydrogel (DTPE hydrogel) obtained in Example 1 formed a dense gradient network structure with a surface pore size (3 μm) much smaller than the internal pore size (13 μm). This structure is beneficial for forming a stable hydration layer and limiting the rapid migration of water and ions, thereby synergistically enhancing anti-swelling and anti-fouling capabilities. At the microscopic level, the addition of EDMA directly changed the pore structure and density of the DMAPS hydrogel. The microstructure of the hydrogel was observed by SEM. The DTP hydrogel had exposed pores on its surface, a loose and rough morphology, and a sponge-like network structure in its cross-section. The pores were large and widely distributed, which was insufficient to effectively limit free water and inhibit solute transport. After the addition of EDMA, the hydrogel matrix was significantly densified, with the average pore size decreasing significantly from 43 μm to 13 μm. This indicates that the DTPE hydrogel network is more fully cross-linked, mechanically stable, and resistant to collapse. Interestingly, a dense granular structure with a pore size of 3 μm appeared on its surface, significantly smaller than that of the DTP hydrogel (37 μm). Figure 4 As shown, in the OH stretching vibration region (3200-3600 cm) -1 The pure DMAPS hydrogel (DTP, 0% EDMA) exhibited broad and prominent peaks, indicating the presence of a large number of hydrogen-bonded water molecules and fully hydrated DMAPS ionic groups in the network.

[0073] The swelling properties of the hydrogels obtained in Examples 1-5 and Comparative Example 1 were tested, and the results are shown in the figure. Figure 5 The hydrogel samples to be tested were immersed in seawater and solutions with salinity ranging from 0.1 to 1.5 M, respectively. The changes in area and weight were measured periodically, and the swelling ratio was calculated. Figure 5 The swelling test results show that the hydrogel obtained in Comparative Example 1 (DTP hydrogel) exhibits significant volume expansion in seawater, with a swelling rate as high as 218% after 150 hours. As the EDMA content increases (Examples 1-5), the anti-swelling ability of the hydrogel is significantly enhanced. When the EDMA content reaches 8 wt% (Example 1), the swelling is effectively suppressed, the volume remains basically stable, and it exhibits an ideal hydration locking effect.

[0074] The mechanical properties of the hydrogels obtained in Examples 1-5 and Comparative Example 1 were tested, and the results are shown in the figure. Figures 6-8 The tensile stress-strain curves of the hydrogel were tested using a universal testing machine, and the Young's modulus, elongation at break, and toughness were calculated. Figure 6 , Figure 7 , Figure 8 As shown, the DTPE hydrogel obtained in Example 1 has the best comprehensive mechanical properties, with a Young's modulus of 731 kPa, a maximum stress of 85 kPa, a maximum strain of 206%, and a toughness of 164 kJ / m³, which is far superior to the comparative example.

[0075] In summary, the hydrogel obtained in Example 1 (DTPE hydrogel containing 8% EDMA) exhibits the best physical properties.

[0076] The adhesion properties of the hydrogels obtained in Example 1 and Comparative Example 1 were tested, and the results are shown in the figure. Figures 9-16 .

[0077] (1) Sample preparation: Cut the hydrogel to be tested into rectangular prisms of equal size for later use.

[0078] (2) Adhesion test on different material substrates: Seven common materials were selected as test substrates: metal, glass, acrylonitrile-butadiene-styrene copolymer (ABS), polyimide (Kapton), polymethyl methacrylate (acrylic) (PMMA), polydimethylsiloxane (silicone rubber) (PDMS), and polyethylene terephthalate (polyester) (PET). The hydrogel sample was attached to the surface of each substrate, and a pressure of 0.5 kPa was applied and held for 10 s. The lap shear test method was used, and the sample was stretched at a rate of 5 mm / min using a universal testing machine. The shear adhesion strength was recorded. The results are shown in […]. Figure 9 and Figure 10 .

[0079] (3) Adhesion test of different biological tissues: Seven biological tissues (freshly extracted) were selected: skin, trachea, heart, liver, kidney, spleen, and lungs. The overlap shear test was performed according to the method in step 2 to determine the adhesion strength between the hydrogel and each tissue. The results are shown in the figure. Figure 11 , Figure 12 .

[0080] (4) Wet adhesion stability test: The hydrogel sample adhered to the pigskin surface was immersed in artificial seawater for 7 days. The adhesion status was observed periodically, and the morphology of the hydrogel was observed on the 7th day. The results are shown in the figure. Figure 13 and Figure 14 Separately, hydrogel was adhered to pig skin and then attached to the surface of a small fan blade. The blade was then immersed in artificial seawater and rotated at 300 rpm for 24 hours. The results were observed to determine if the gel detached. Figure 15 .

[0081] (5) Burst pressure test: A 2 mm diameter through hole was made in the pigskin, and the hydrogel was sealed in the through hole. Pressure was slowly applied to one side of the through hole using a pressure pump, and the maximum pressure when the seal failed was recorded, which is the burst pressure. The results are shown in […]. Figure 16 .

[0082] The hydrogel obtained by this invention exhibits rapid wet adhesion and long-term stability in seawater. For example... Figure 9 , Figure 10 As shown, the DTPE hydrogel obtained in Example 1 exhibits strong wet adhesion to many substrates, with adhesion strengths of 43.1, 20.1, 18.7, 22.3, 28.1, 11.4, and 20.1 kPa, respectively. Figure 11 , Figure 12 As shown, the hydrogel achieved stable wet adhesion to tissues such as skin, trachea, heart, liver, kidney, spleen, and lungs. Even with distortion at the tissue-hydrogel interface, no interfacial delamination was observed. Overlap shear tests further quantified the tissue adhesion strength, which were 54.1, 42.3, 27.7, 24.7, 11.7, 15.5, and 23.2 kPa, respectively. Figure 13 As shown, the DTP hydrogel exhibited significant volume expansion after 7 days of immersion, accompanied by the migration of PANI:PSS (decolorization of the solution). This leaching behavior reduced the effective contact area, exacerbated interfacial micro-exfoliation, and ultimately led to delamination. Figure 14As shown, the DTP hydrogel exhibited significant swelling after immersion, with large pores and irregular wrinkles appearing on its surface. In stark contrast, the DTPE hydrogel remained almost unchanged in size under the same conditions, with negligible leaching of the conductive phase, and maintained strong adhesion throughout. This further validates the long-term dynamic adhesion of the DTPE hydrogel in seawater. Figure 15 As shown, under more demanding dynamic conditions, we attached the hydrogel to a small fan blade and immersed it in seawater for high-speed rotation; after 24 hours, the DTPE hydrogel remained adhered, while the DTP hydrogel obtained in Comparative Example 1 failed due to expansion and leakage. To further investigate the superior adhesion properties of the DTPE hydrogel, its burst pressure resistance was also measured. Figure 16 As shown, the burst pressure of the DTPE hydrogel (215 kPa) exceeds that of the DTP hydrogel (89 kPa). Mechanistically, EDMA increases the node density, thereby suppressing permeation-driven volume expansion and stress relaxation in seawater. Although the high crosslinking density slightly restricts the interpenetration of fragments and leads to a slight decrease in initial adhesion, the resulting dimensional stability, impermeability, and fatigue resistance significantly improve long-term adhesion retention and dynamic peel resistance. Therefore, topologically constrained EDMA enables the hydrogel to achieve stable adhesion in seawater environments with cross-tissue and dynamic disturbances, providing a reliable guarantee for stable signal acquisition and long-term monitoring under complex marine conditions.

[0083] The synergistic antifouling performance of the hydrogels obtained in Example 1, Comparative Example 1, and Comparative Example 2 was tested, and the results are shown in [the table below]. Figures 17-22 .

[0084] (1) Sample preparation: Cut the hydrogel to be tested into thin slices of equal size, disinfect them with 75% ethanol solution, rinse them three times with sterile physiological saline, and set them aside; and select a sterile 304 SS metal sheet of the same size as the hydrogel as a blank control (Control).

[0085] (2) Protein adsorption test: The sample was immersed in bovine serum albumin (BSA) solution (concentration 1 mg / mL) and incubated at 37℃ for 24 h. The adsorbed protein on the surface was then eluted, and the BSA content adsorbed on the sample surface was measured. The protein adsorption amount per unit area was calculated. The results are shown in the figure. Figure 17 .

[0086] (3) Antibacterial performance test: Typical bacteria from the marine environment (Pseudomonas aeruginosa) were selected. P. aeruginosa Bacillus vinifera B. vietnamensis Escherichia coli E. coli Staphylococcus aureus S. aureis The prepared concentration is approximately 1×10⁻⁶. 6CFU / mL bacterial suspension; contact killing ability was assessed by bacterial inhibition zone test; optical density (OD) at 600 nm wavelength was monitored. 600 The antibacterial effect against planktonic bacteria was verified; microbial biomass was quantitatively determined using the adenosine-5-triphosphate (ATP) assay; the sustained ability of the hydrogel to inhibit biofilm formation after 5 days of long-term co-cultivation was verified by colony counting experiments; the survival rate of bacteria on the hydrogel was observed using fluorescence staining; and the integrity of the biofilm was morphologically observed using scanning electron microscopy (SEM). The results are shown in [Figure number missing]. Figures 18-22 .

[0087] In contrast, all samples coated with hydrogel showed a significant reduction in protein adsorption. Specifically, such as Figure 17 As shown, the DTPE group had the lowest BSA adhesion rate (0.04 mg / cm). 2 This confirms the remarkable effectiveness of hydrogels in inhibiting nonspecific protein blockage. Figure 18 As shown, the DPE, DTP, and DTPE groups all formed obvious antibacterial zones, with the DTPE hydrogel exhibiting the strongest inhibitory effect against all bacterial strains. Furthermore, the antibacterial durability of the hydrogel coatings was comprehensively evaluated. After 5 days of long-term co-cultivation, the optical density (OD) at 600 nm was monitored. 600 To verify its antibacterial effect against planktonic bacteria. For example... Figure 19 As shown, the OD of the DTPE group 600 The lowest value demonstrates that the hydrated polyphenol network possesses broad-spectrum and significant antibacterial activity. Microbial biomass was quantitatively determined using an adenosine-5'-triphosphate (ATP) assay. Figure 20 As shown, the lowest relative light unit (RLU) observed among all bacteria further confirms that the DTPE hydrogel possesses the best sustained antibacterial activity. Simultaneously, we verified the hydrogel's sustained ability to inhibit biofilm formation after 5 days of long-term co-cultivation using colony counting experiments. Figure 21 As shown, although both DPE and DTP groups exhibited antibacterial activity, DTPE demonstrated the strongest biofilm-killing ability. Furthermore, to directly observe the bactericidal effect of the coating on bacteria attached to the hydrogel, we used fluorescent staining to observe the bacterial survival rate on the hydrogel. Figure 22As shown, the control group had a dense bacterial layer on its surface, with bacterial cells mainly exhibiting green fluorescence, demonstrating strong bacterial survival and proliferation capabilities. In contrast, the DTPE group showed the lowest green fluorescence density, with residual bacteria mainly exhibiting red fluorescence, indicating cell membrane damage or death. This confirms that DTPE hydrogel can effectively disrupt bacterial cell walls and inhibit biofilm aggregation after prolonged exposure. Furthermore, to verify the bactericidal effect at the microscopic level, we performed morphological observation of the biofilm integrity using scanning electron microscopy (SEM). After long-term co-culture, the control group surface showed densely packed bacteria with intact morphology, demonstrating stable biofilm formation. Conversely, DTPE showed a significant reduction in bacterial numbers, with residual bacteria exhibiting obvious morphological damage (wrinkling and depressions), confirming that DTPE hydrogel exerts its bactericidal effect by disrupting bacterial cell membranes. In conclusion, DTPE hydrogel demonstrates excellent performance in both rapid sterilization and long-term inhibition of biofouling formation.

[0088] Multimodal bioelectrical signal acquisition tests were performed on the hydrogels obtained in Example 1 and Comparative Example 1. The results are shown in [Figure 1]. Figures 23-27 .

[0089] (1) Test samples: DTPE hydrogel in Example 1, DTP hydrogel in Comparative Example 1, and commercially available Ag / AgCl gel electrode (commercial electrode).

[0090] (2) Conductivity stability test: The hydrogel was immersed in seawater and its conductivity was monitored over a long period of time using the four-probe method. At the same time, its salt adaptability was tested in solutions with different salt concentrations (0.1-1.5 M).

[0091] (3) Sensing performance test: The relative resistance change (RRC) of the hydrogel was measured by applying different strains using a tensile testing machine, and the sensitivity (GF) was calculated. Cyclic loading-unloading test was performed to evaluate its response / recovery time and cyclic durability.

[0092] (4) Bioelectric signal acquisition test: Hydrogels were attached to the wrist and chest of the human body as electrodes. The subject was immersed in seawater and the electrocardiogram (ECG) and electromyogram (EMG) signals were recorded using a biosignal acquisition system.

[0093] The hydrogel (DTPE hydrogel) obtained in Example 1 of this invention exhibits excellent conductivity stability and sensing performance. In long-term conductivity testing, due to the infiltration of a large number of ions from seawater, the conductivity of the hydrogel (DTP hydrogel) obtained in Comparative Example 1 increased unstablely by 124% after 150 h. In contrast, as... Figure 22 As shown, the DTPE hydrogel maintains almost unchanged conductivity after being immersed in seawater for 150 h, while also retaining a high conductivity of 22 S / m. Figure 24As shown, under different salt concentrations, DTP hydrogels undergo drastic volume expansion with increasing salinity, resulting in a sharp shift in conductivity, while DTPE hydrogels exhibit minimal size change and demonstrate excellent salt-adaptive conductivity stability.

[0094] In terms of sensing performance, such as Figure 25 As shown, the DTPE hydrogel exhibits high sensitivity (GF = 6.71) and stable high linear response (R0). 2 =0.99), and GF remained almost unchanged (6.51) after being immersed in seawater for two days. In addition, it also has a fast response time (100 ms), recovery time (90 ms) and strong cycle durability (signal amplitude remained almost unchanged after 200 load-unload cycles).

[0095] In bioelectrical signal acquisition, such as Figure 26 , Figure 27 As shown, the interfacial resistance of the DTPE hydrogel (446 Ω) is significantly lower than that of the commercial electrode (1686 Ω). The DTPE hydrogel maintains a high signal-to-noise ratio (SNR) (25 dB) even after prolonged immersion in seawater, while the SNR of the commercial electrode decreases from 20 dB to 15 dB. Electrocardiograms recorded on the DTPE hydrogel show higher and more stable R-wave amplitudes, clear "PQRST" morphology, and a flat TP baseline, while the commercial electrode exhibits low-frequency drift and blurred "QRS" boundaries. In electromyography (EMG) signal testing, the DTPE hydrogel shows a near-zero resting segmental baseline with minimal high-frequency texture, while the commercial electrode exhibits significant baseline drift, interspersed with broadband noise and mechanical artifacts, with burst peaks almost completely masked by noise. These results demonstrate that the DTPE hydrogel can acquire high-quality, low-drift physiological signals in seawater.

[0096] In summary, this invention proposes a hydration-locked percolation strategy for constructing jellyfish-inspired hydrogels (DTPE). This hydrogel achieves excellent anti-swelling properties, antifouling capabilities, cross-substrate wet adhesion, and stable low drift conductivity across a wide salinity range in seawater. Notably, the hydrated polyphenol network forms a synergistic antifouling system that both repels and kills fouling organisms, fundamentally inhibiting early adsorption and biofilm evolution, thus enabling long-term operation. Simultaneously, stable interpenetrating electron channels effectively lock charge transport paths, preventing disturbances caused by salt penetration and fouling, thereby enabling long-term, low-noise, high signal-to-noise ratio acquisition of multimodal physiological signals. The results of Example 1 and its comparison with Comparative Example 1 show that, by introducing the hydrophobic crosslinking agent EDMA, the hydrogel of the present invention (Example 1) exhibits significantly greater dimensional stability and adhesion durability under long-term seawater immersion and dynamic disturbance compared to the hydrogel without EDMA (Comparative Example 1). Its burst pressure (215 kPa) is much higher than that of Comparative Example 1 (89 kPa), effectively solving the swelling and detachment problems under high-salt environments. The results of Example 1 and its comparison with Comparative Example 2 demonstrate that the hydrogel of the present invention (Example 1) forms a synergistic antifouling system through a hydration-polyphenol network, which can both repel and kill fouling organisms. Its protein adsorption capacity (0.04 mg / cm³) is [not specified in the original text]. 2 The levels were significantly lower than those in the control group (0.59 mg / cm²). 2 It exhibits the strongest broad-spectrum antibacterial and anti-biofilm formation capabilities, fundamentally inhibiting early adsorption and biofilm evolution. Example 1 and its comparison with commercial electrodes show that the hydrogel of this invention (Example 1) possesses stable interpenetrating electron channels, effectively locking the charge transport path (22 S / m), preventing disturbances caused by salt penetration and fouling. Its interface resistance (446 Ω) and signal-to-noise ratio (25 dB) are significantly superior to those of commercial electrodes (1686 Ω, 15 dB), thus enabling long-term, low-noise, and high signal-to-noise ratio acquisition of multimodal physiological signals. Therefore, this invention successfully overcomes the long-standing stability bottleneck in marine bioelectronics, opening up new avenues for long-term, high-fidelity sensing in harsh aquatic environments.

Claims

1. A method for preparing a marine antifouling conductive hydrogel, characterized in that: Amphoteric monomers, N-hydroxysuccinimide acrylate, and tannic acid were dissolved in an aqueous dispersion of polyaniline:polystyrene sulfonic acid. A hydrophobic crosslinking agent was added, and the mixture was magnetically stirred at room temperature to obtain a pregel solution. An initiator was added to the pregel solution, and after stirring until homogeneous, a polymerization reaction was carried out to obtain a marine antifouling conductive hydrogel. The zwitterionic monomer is [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide; The hydrophobic crosslinking agent is ethylene glycol dimethacrylate; The mass ratio of the zwitterionic monomer, hydrophobic crosslinking agent, polyaniline:polystyrene sulfonic acid aqueous dispersion, N-hydroxysuccinimide acrylate, tannic acid, and initiator is 100 : 2~10 : 20~30 : 50~75 : 200~300 : 5~10.

2. The preparation method according to claim 1, characterized in that: The initiator is ammonium persulfate.

3. The preparation method according to claim 1, characterized in that: The mass concentrations of both polyaniline and polystyrene sulfonic acid in the polyaniline:polystyrene sulfonic acid aqueous dispersion are 1-3 wt%.

4. The preparation method according to claim 1, characterized in that: The polymerization reaction conditions are 70~90℃ for 0.5~2 h.

5. The marine antifouling conductive hydrogel prepared by the method according to any one of claims 1 to 4.

6. The marine antifouling conductive hydrogel according to claim 5, characterized in that: The marine antifouling conductive hydrogel has a surface pore size of 2-5 μm and an internal pore size of 10-20 μm; its electrical conductivity is 15-25 S / m, wet adhesion strength is 10-60 kPa, burst pressure is ≥150 kPa, Young's modulus is 300-900 kPa, maximum tensile strain is 150%-220%, and mechanical toughness is 80-180 kJ / m. 3 .

7. The application of the marine antifouling conductive hydrogel according to claim 5 in the preparation of marine antifouling biosensor materials.

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