| Titanium and its alloys were widely used in orthopedic and dental fields asimplants due to their excellent mechanical properties and moderate biocompatibility.Orthopedic implants failures are mainly related to poor osseointegration and/or bacterialinfection. Surface functionalization of an implant is one promising alternative forimproving osseointegration and/or reducing bacterial infection.In this study, titanium (Ti) substrates were functionalized with a polydopamine(PDOP) film as the intermediate layer for further immobilization of chitosan-lauric acid(Chi-LA) conjugate. Firstly, chitosan-lauric acid conjugate (1%,1.67%,2.5%) weresynthesized via esterification and characterized by FIRT and1HNMR, the result showedthat chitosan-lauric acid conjugate were successful synthesized. Then, scanningelectron microscopy(SEM) and water contact angle were employed to detect the changeof Ti substrates at various stages of surface modification to verify the successfuldeposition of PDOP film and immobilization of Chi-LA conjugate. Cell experiments invitro confirmed that the adhesion, viability, alkaline phosphatase activity(ALP) andmineralization of osteoblasts were remarkably enhanced by the Chi-LA immobilized Tisubstrates. In this paper, we choose two kinds of common bacteria, Staphylococcusaureus (S.aureus) and Pseudomonas aeruginosa (P. aeruginosa) for antibacterial assay.Bacteria grown onto Chi-LA modified Ti substrates surface can significantly inhibitbacterial adhesion in the early "critical period" after culture for4h. When incubation for12h, the result displayed that Chi-LA conjugate has a good short-term antibacterialperformance. Finally, spread plate method was employed to verify the long-termantibacterial rate for Chi-LA modified Ti substrates after culture for4and7d, the resultindicated that Chi-LA immobilized Ti substrates could effectively inhibit the growth ofbacteria, and showed good performance in sustained antibacterial assay. This studyprovides a promising approach for promoting osteoblasts functions and concurrentlyreducing bacteria adhesion on Ti substrates, which would be attractive for surfacemodification of titanium-based orthopedic implants. |
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