Poly-L-Lysine/Sodium Alginate Coating Loading Nano-Silver For Improving Antibacterial Effect Of Dental Implants

Background:In recent years,commercial Ti and its alloy implant have been applied in implantation,due to their excellent biocompatibility,low elastic modulus,lasting stability.However,lack of antibacterial capabilities will increase the chance of implant failure,which will be a major challenge for the application of titanium-based implant devices.They often need modifications to obtain antimicrobial activity.The electrostatic self-assembly is a technique which base on the successive adsorption of poly-anions and poly-cations on the surface of material through electrostatic interactions.This technique is is widely used in the preparation of biological coatings due to combine two or more charged molecules and a large number of reactive groups for further modification.There are many ways for incorporate antibacterial reagents into the titanium surface,such as coating,covalent grafting,eta.Silver and silver nanoparticles（Ag NPs）have long been used as antibacterial agents in the application of dental materials due to their antibacterial activity against a broad spectrum of bacteria and low bacterial resistance.Dopamine is an effective linking molecule for integrating antibacterial agents.It can reduce metal ions in situ to form metal elements.In addition,its ability of chelate metal ions make them become the crystallization site of the mineralization process,and quickly form a to mineralized layer.Purposes:The study prepared a coating of polycation（PLL）/polyanion（SA）multilayer films on the alkali-heat treated titanium surface,and then coated polydopamine layer.Finally,the coated-Ti plats were immersed in Ag NO₃solution to in-situ deposition of Ag NPs on the surface for obtaining antibacterial property.And which evaluated its biological performance.Methods:Prepare the antibacterial coating on the porous titanium surface to prevent infection,which was initialized by deposition of poly-L-Lysine（PLL）/sodium alginate（SA）/PLL self-assembly film,followed by dopamine deposition and then in-situ reduction for silver nanoparticles（Ag NPs）by dopamine.Surface zeta potential,SEM,XPS,UV-vis and water contact angle demonstrate that the coating after each steps was successfully prepared.The release contents of Ag⁺obtained by ICP-AES maintained more than 27 days.The biological activity of the modified titanium interact with biological environment in terms of cyto-compatibility and antibacterial property was investigated using MC3T3 and S.mutans and S.aureus strains in vitro,respectively.Result:It was proved the success of surface modification through a series of test of the surface zeta potential,water contact angle measurement,scanning electron microscope（SEM）morphology observation,XPS composition analysis and release of silver ion test.In the bacterial inhibition experiment,silver-loaded titanium was show a clear ZOI,the concentration of bacterial suspension was significantly reduced at 48h.Little green viable bacteria adhered and a number of dead cells（red）on the the surface of Ag-loaded Ti using microscopy and bacterial clumps decreased significantly,which inhibited the growth of biofilm on the surface of titanium with silver.The biological experiment showed that the coating caused a cell damaged,however good viability of cells was obtained by mineralized treatment.Conclusion:This design prepared an antibacterial and bioactive surface by a simple method,which could have potentially valuable applications in the fields of dental-and orthopedic-related.