硬组织植入物需求量大，但依然有约10%的植入物在10~20年内就过早地失效，感染和骨整合不良是造成这类生物惰性材料植入失败的主要原因，通过表面改性使其兼具良好的抗菌性能和骨整合能力是当前的研究热点和前沿。但目前研究存在三个问题：(1)由于抗菌剂被动释放而产生的细胞毒性不利于早期骨整合，使感染的风险加大；（2）有限的携载量和无效释放导致抗菌周期较短；（3）易于产生耐药菌，抗菌效力有待提高。为此，本项目拟以具有pH值响应特性、生物相容性良好的壳聚糖基复合材料为载体，携载银/抗生素复合抗菌剂，在硬组织材料表面设计和构建细菌触发自卫型银/抗生素复合涂层，揭示载体与抗菌剂之间相互作用机制、pH响应释放和抗菌机理，从而建立细菌触发型银/抗生素复合涂层与细菌、细胞和组织之间的生物学相互作用机制及其有效调控方法，为硬组织植入物表面功能化提供科学依据，相关的研究具有重要的研究价值和应用前景。

Hard tissue implants are in great demand, about 10% of which will fail to fulfill their functions within one or two decades, with postoperative infection and poor osseointegration as major causes for those implant failures. To enable the implant surfaces with combined antibacterial properties and osteointegrative potentials has been the focuse and frontier to tackle these issues. However, there are three problems in this scenario: (1) the passive release of antibacterial agent will induce cytotoxicity, deteriorate the early osseointegration process, and increase the infection risks; (2) the limited loading amount and the invalid release of the reagent will reduce the duration of its antibacterial activity; (3) these functionalized surfaces may result in the formation of drug-resistant bacteria and their antibacterial effects remain to be improved. Therefore, in this project, a bacteria-triggered self-defensive silver/antibiotics composite coatings are designed and constructed on the surface of implant materials by using chitosan-based materials as carriers with pH responsive and biocompatible properties and exploiting silver/antibiotics as the antibacterial agents, to reveal the interaction mechanism between carriers and antibacterial agents and to study the pH responsive release behavior and the antibacterial mechanism of the agents within the coatings. This work will provide scientific basises for the surface functionalization of hard tissue implant materials, in terms of the interaction mechanisms among the proposed composite coatings, bacteria, cells and tissues with effectively controllable approaches, which show significant research values and application prospects .