Abstract: Objective To investigate the reaction time influence on the antibacterial property and cytocompatibility of polydopamine/silver nanoparticles modified porous titanium. Methods A bioinspired polydopamine （PDA） layer was deposited on titanium surface by polymerization. By adjusting the response time of nanosize silver particles （15 min, 30 min, 60 min） of the modified titanium, different concentration of silver nanoparticles modified titanium coated by polydopamine were prepared. Using scanning electron microscopy （SEM）, cell adhesion, cell toxicity and sterilization rate examination to evaluate the in vitro biocompatibility and antibacterial properties of polydopamine modified titanium with load of different concentration of silver nanoparticles. Results The modified titanium surface material with the response time of 15 min in nanosize silver particles loading, showed better cell adhesion ability, lower cytotoxicity and more satisfactory antibacterial properties than the others. Conclusion By adjusting the reaction time of nano silver deposition, the silver ion release quantity is adjustable, and the polydopamine/silver nanoparticles modified porous titanium, which have good cell compatibility and strong antibacterial ability, can be gained.

Key words: Porous titanium, Polydopamine, Silver nanoparticles, Biocompatibility, Reaction time