| Purpose: Dental implants are widely used in the repair of denture defects and missing dentures due to their high efficiency in the recovery of chewing occlusal and aesthetic functions,but the failure rate is still about 4.4% in the early stage of implantation.As inert materials,titanium and its alloy are the preferred materials for implants,but they do not have antibacterial properties and the surface is easy to gather and adhere to bacteria,thus forming bacterial biofilms and causing infection complications.The natural mucosal barrier of the body is destroyed in the process of implant implantation,and the sealing quality of the soft tissue around the neck of the implant through the skin or mucosa is closely related to the bacteria around the implant.Poor sealing of the soft tissue of the neck of the implant may lead to a large amount of plaque gathering in the neck of the implant,thus causing inflammation,and bone resorption and affecting bone integration,leading to early implant failure.Therefore,antibacterial modification on the implant surface to inhibit or kill bacteria on the material surface and surrounding environment is very important for the establishment and maintenance of a biological seal in the soft tissue around the implant.In this study,brown algal polyphenol was used as the carrier,and chlorhexidine was used as a broad-spectrum antibacterial agent.A mixed coating of brown algal polyphenol/chlorhexidine was constructed on a porous titanium surface by the liquid phase blending deposition method.By regulating the concentration of chlorhexidine,the surface was given more excellent and lasting inhibition or killing of planktonic bacteria on the surface of the titanium implant and surrounding tissues to achieve good soft tissue closure.Methods: In this study,micro/nanoporous structures were constructed on the surface of titanium using hot alkali treatment(as the control group,labeled as p Ti).Brown algae polyphenols were blended with different concentrations of chlorhexidine(the concentrations of brown algae polyphenols were 1.5mg/m L,and chlorhexidine concentrations were 0.1,1,and 5 mg/m L),and then the alkali-activated titanium sheets were soaked into the blend.the prepared experimental group samples were labeled as CHX:0.1,CHX:1,and CHX:5.Scanning electron microscope(SEM)was used to observe the surface morphology of the sample,water contact Angle measuring instrument(WCA)was used to measure the surface hydrophilicity of the sample,and X-ray photoelectron spectroscopy(XPS)was used to analyze the composition and content of elements on the surface of the sample to analyze whether the coating was successfully prepared.the particle size and zeta potential of the products in the mixture were analyzed by a particle size analyzer.the functional groups of the products were detected by Fourier infrared spectroscopy.the interaction mechanism between chlorhexidine and brown algae polyphenol was analyzed.the in vitro antibacterial ability of the sample surface was evaluated by turbidity method,bacteriostatic ring test,and SEM observation.the short-term antibacterial ability of the samples in vivo was evaluated by placing the samples under the skin for a short time.Cytotoxicity test(MTT)and fluorescence staining were used to evaluate the cytocompatibility of the samples.the in vivo use of the implant was simulated by bacteria-cell competitive adhesion to evaluate the effect of the material on cell adhesion in the presence of bacteria.the samples were implanted into the subcutaneous environment with bacteria for a long time,and tissue sections and hematoxylin-eosin(HE)staining were used to evaluate the influence of the materials on the inflammatory response of the surrounding tissues in the environment with bacteria in vivo.Results: The XPS results showed that the reduction of the Ti peak in the three experimental groups indicated that the coating was successfully constructed.The appearance of the Cl2 p peak and the enhancement of the N1 s peak indicated that chlorhexidine was successfully bound to the material surface.With the increase of chlorhexidine concentration in the mixture,the atomic percentage of Cl and N on the preparation surface increased,indicating that more chlorhexidine was present on the preparation surface.High-resolution analysis of oxygen revealed the presence of large amounts of phenolic hydroxyl and quinone groups,which proved that brown algae polyphenols were bound to the surface of the material.The results of the water contact Angle measurement showed that the surface hydrophilicity of the three experimental groups was significantly worse than that of the control group,and increased with the increase of CHX concentration.However,The hydrophilicity of CHX:1 and CHX:5 had little difference and was much higher than that of p Ti and CHX:0.1.the SEM results showed that the surface of p Ti was porous and reticular,the pores on CHX:0.1 were sporadically filled with pellets,the holes on CHX:1 were completely filled with a small number of spheres,and the holes on CHX:5 were filled with a large number of spherical particles.These results show that chlorhexidine/phlorotannins coating is successfully constructed on the surface of titanium after alkali heat treatment.Zeta potential and infrared results analysis of chlorhexidine/phlorotannins mainly through hydrogen bond interaction,and because CHX:1 and CHX:5 formed complex particles with positive charges more easily to bond with negatively charged p Ti.After 7 days and 14 days of PBS immersion,there were still large amounts of sediments on the surface of CHX:1and CHX:5,which proved that the coating had a certain stability.The results of the turbidity method and bacteriostatic cycle showed that all three experimental groups inhibited the bacterial proliferation around the samples,and the inhibitory ability increased with the increase of CHX concentration,and the inhibitory ability also decreased with the extension of the sample soaking time in PBS,but the antibacterial stability of CHX:1 was better.SEM results showed that the three experimental groups significantly inhibited the adhesion of bacteria on the sample surface,and the inhibition trend was the same as that of the surrounding bacteria.In vivo,antibacterial results showed that CHX:1 and CHX:5 had good antibacterial activity vivo.Cytocompatibility results showed that CHX:1 and CHX:5 were not conducive to cell adhesion,but their cytocompatibility was significantly improved with the release of the coating(soaked in PBS).Bacterial cell co-culture showed that the surface of CHX:1 and CHX:5 prevented bacterial adhesion and a large number of cells adhered.HE staining of the implantation site of the in vivo samples showed that CHX:1 and CHX:5 samples significantly inhibited the inflammatory response of the surrounding tissues.Conclusion: The antibacterial surface of chlorhexidine/phlorotannins was successfully prepared by liquid phase blending deposition.When chlorhexidine concentration was 1and 5mg/m L,the antibacterial performance of the prepared surface was better and more stable.In the presence of bacteria,the adhesion of cells was more effectively ensured and the inflammation caused by bacteria was inhibited.therefore,the prepared surface can effectively improve the biological sealing effect of implant neck in a bacterial environment,reduce the incidence of infectious complications,and provide an effective technology for implant surface modification. |
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