[Primary study on the antibacterial property of silver-loaded nano-titania coatings].

Objective: To study the preparation and characteristics of silver-loaded nano-titania coating so as to develop a bioactive implant material with antibacterial property.

Methods: Plasma sprayed nano-titania coatings were immersed in 1%, 5%, and 9% AgNO3 solution to load silver. The loaded silver and its distribution were evaluated by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). After optimizing the preparation process, the release rate of silver from the nano-titania coating was measured in deionized water, its corresponding in vitro cytotoxicity and antibacterial activity were also examined.

Results: The loaded silver was in proper quantity and distributed evenly on the nano-titania coatings after immersion in 5% AgNO3. A burst release of the silver could be detected. The quick release of silver from the titania coatings sustained about 12 days in deionized water, which had no obvious influence on the surface morphology of titania coatings. The loaded silver did not inhibit the osteoblast proliferation (P = 0.1) and alkaline phosphatase expression (P = 0.06), however, it effectively inhibited the survival and growth of Staphylococcus aureus for 12 days: the zone of inhibition reached 3.81 +/- 0.8 mm with a bacteria killing rate of 100%.

Conclusions: It is economical and effective to prepare the silver-loaded nano-titania coatings by 5% AgNO3 solution. The loaded silver has good antibacterial function, and shows no obvious effect on the physical and biological properties of nano-titania coatings.