为扩展纳米TiO2光谱响应范围，提高其可见光催化抗菌性能，本文以商业纳米TiO2为原料，采用Ag化学沉积，N、S非金属元素掺杂制备改性P25抑菌材料（Ag-P25、Ag-N-P25、Ag-S-P25），研究这三种材料在可见光下对大肠杆菌的抑菌效果。研究表明，三种抑菌材料对大肠杆菌均有良好的抑制效果，其抑菌率随光照时间延长而不断上升。三种材料抑菌效果的强弱顺序为：Ag-S-P25、Ag-N-P25、Ag-P25。当光照时间为100 min时，三者对大肠杆菌的抑菌率均达100%，与纯P25的抑菌率（79%）相对比，提高了21%。通过扫描电镜观察和提取菌体质粒DNA的电泳检测表明，三种材料对大肠杆菌菌体造成破坏，引起DNA泄漏，导致菌体死亡。通过研究讨论改性P25材料对大肠杆菌的灭活机理，可为具有抗菌功能的新型保鲜材料的研究开发提供理论和实验依据。

To broaden the spectral response of nanoscale TiO2 and to enhance its visible-light photocatalytic antibacterial activity, in this study, chemical deposition of silver (Ag) and the doping of nonmetal elements nitrogen (N) and sulfur (S) was performed to prepare modified P25 antibacterial materials (Ag-P25, Ag-N-P25, and Ag-S-P25) with commercial TiO2 nanoparticles as the raw material. The antibacterial effects of these three P25 materials were studied against Escherichia coli under visible light. The study showed that all the three antibacterial materials had good inhibitory effects on E. coli growth. The antibacterial rate of the modified P25 materials increased with the extension of illumination time under visible light. The antibacterial effects of the three materials were in the following order: Ag-S-P25 > Ag-N-P25 > Ag-P25. When the materials were illuminated for 100 min, the antibacterial rate of Ag-S-P25, Ag-N-P25, and Ag-P25 reached 100%, which was 21% higher than that of pure P25 material. The results from scanning electron microscopy (SEM) and electrophoresis of the bacterial plasmid DNA showed that the E. coli cells were damaged by these three materials, which also caused the leakage of plasmid DNA and led to the death of bacteria. Further study and discussion on the E. coli inactivation mechanism of modified P25 materials can provide a theoretical and experimental foundation for the development of new antibacterial materials for food preservation.

国家自然科学基金资助项目（31371855）；广州市科技项目（2014J4100150）