脉冲电化学驱动壳聚糖原位调控制备羟基磷灰石/银复合涂层

采用脉冲电化学驱动壳聚糖原位调控制备了具有抗菌性的羟基磷灰石/银纳米复合涂层.考察了电解液中银离子浓度、钙磷盐浓度等对复合涂层的形貌及成分的影响.探讨了壳聚糖调控羟基磷灰石和银纳米粒子的形成机理,发现在本研究的较佳实验条件为电位-1.3 V,Ag~+浓度为0.06 g·L~(-1),Ca~(2+)浓度为5 mmol·L~(-1).在此基础上对复合涂层的生物活性、生理稳定性能、抗菌性能进行分析.结果表明:复合涂层呈纳米球状,由羟基磷灰石、银、壳聚糖三相组成,并且表面有一层壳聚糖覆盖.银纳米粒子和羟基磷灰石纳米粒子在复合涂层中均匀分布.将复合涂层浸泡在SCPS溶液中37°C浸泡矿化10天后,在复合涂层表面生产细针状排列整齐的羟基磷灰石,且在(002)晶面25.8°处发生显著择优生长,表明复合涂层在快速矿化液中能诱导磷灰石生成,生物活性好.将复合涂层浸泡在37°C PBS溶液中考察其生理稳定性,壳聚糖对复合涂层中Ca~(2+)和Ag~+实现双重离子释放,且降低了离子释放速度,涂层具有良好的生理稳定性.抗菌实验表明复合涂层对大肠杆菌和金黄色葡萄球菌抗菌率达到99%以上,抗菌能力强.

Pulse Electrochemical Driven Synthesis of Hydroxyapatite and Silver Composite Coatings by Chitosan Mediation

Attention has been always paid to long-term antibacterial property of biomaterial surface.In this study,the antibacterial hydroxyapatite (HA) and silver (Ag) composite coatings are prepared in situ using pulse electrochemical driven by regulation of chitosan.The influence of both Ag+ and the salt on the composition and the morphology of the composite coatings was investigated.The underlying mechanism regulated to HA and Ag nanoparticles formation by chitosan (CS) was studied.The study showed that the optimized experimental conditions were the following:potential of-1.3 V,Ag+ concentration of 0.06 g·L-1,Ca2+ concentration of 5 mmol·L-1.Under these conditions,the biological activity of the composite coatings,their antibacterial properties and physiological stability were examined.The results showed that the composite coatings were composed of nano-spherical with three-phases of HA,Ag and CS,where Ag and HA nanoparticles were uniformly distributed in the composite coatings,and covered by a layer of CS.The composite coatings were immersed in supersaturated calcium phosphate solution (SCPS) for mineralization for 10 days at 37 ℃.The biomimetic mineralization process of the surface of the composite coatings produced fine aticular neat rows of HA with preferential growth of the (002) crystal plane at 25.8℃.This indicated that the composite coatings could form apatite in the fast mineralized solution.Also,it was found that bioactivities of the composite coatings were pretty good.In order to examine the physiological stability of the composite coating,the composite coating was immersed in phosphate buffer solution (PBS) at 37 ℃.In composite coatings,the presence of CS reduced the double ion release rates of Ca2+ and Ag+,leading to good physical stability.The antibacterial testing of the composite coatings on bacterial strains,including Escherichia coli and Staphylococcus aureus,illustrated antibacterial properties with rates over 99％.