载银纳米氧化钛涂层抗菌性能的初步研究

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

目的探讨载银纳米氧化钛生物陶瓷涂层的制备和表征，以期获得具抗菌作用的植入物涂层材料。方法将等离子体喷涂纳米氧化钛涂层浸入1％、5％、9％的硝酸银溶液中载银，通过背散射电镜和能谱仪考察各自载银量和银分布，选择合适的载银工艺。对以该工艺制备的载银涂层进行银离子缓释、成骨细胞毒性和体外抗菌性能试验。结果5％硝酸银溶液使得涂层载银量适中，银分布均匀。载银纳米氧化钛涂层的银离子爆发性释放明显，快速释银时间持续12d；释银后涂层表面形貌较原始氧化钛涂层无明显改变。第1、3、5天时成骨细胞在载银前后的涂层表面对阿尔玛蓝染料的还原率[（18．3±1．8）％／（24．8±2．5）％；（21．8±3．7）％／（25．0±1．5）％；（34．0±1．5）％／（34．8±3．5）％]的差异无统计学意义（P〉0．05）；同时测定的成骨细胞在载银前后的涂层表面碱性磷酸酶的分泌量[（20．0±0．6）U／L／（20．0±1．0）U／L；（21．0±0．6）U／L／（20．0±0．6）U／L；（20．0±1．0）U／L／（20．0±0．0）U／L]差异无统计学意义（P〉0．05）；抑菌环直径最为（3．81±0．8）mm。抑菌环持续达12d，菌落数试验抗菌率100％。结论以5％硝酸银溶液制备载银纳米氧化钛涂层经济而高效。载银未改变纳米氧化钛原有的理化特性和生物相容性，且使其具备了良好的体外抗菌性能。

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.