细菌感染是严重威胁着人们生命健康的主要问题之一. 与传统抗生素疗法相比, 新型抗菌策略光热疗法(PTT)展现出可控、微创及不易使细菌产生耐药性的优良性能. 然而单模形式下PTT疗法并不理想, 且高温下通常伴随着炎性反应等副作用, 联合抗菌策略可有效解决这一问题. 本研究制备了富含羧基的氧化介孔纳米碳球(OMCN), 通过酰胺化反应, 共价接枝聚六亚甲基双胍(PHMB), 得到OMCN-PHMB纳米平台. 实验结果表明, OMCN的光热性能具有良好的浓度与近红外光照功率依赖性. 在808 nm激光照射下, OMCN-PHMB的体内外联合光热治疗效果显著优于单一模式下的其它治疗组, 且组织学分析结果表明, 该纳米平台对小鼠的主要器官没有产生明显的毒性, 具有较高的生物相容性.

Bacterial infection is one of the major problems that seriously threaten people's life and health. In recent years, photothermal therapy (PTT), which uses photothermal conversion nanomaterials to convert optical energy into thermal energy for sterilization under specific wavelength laser irradiation, has aroused wide interest of researchers. Compared with traditional antibiotic therapy, the new anti-bacterial strategy photothermal therapy shows the excellent performance of controllable, minimally invasive and less bacterial resistance. However, monomodal PTT therapy is not ideal because it is often associated with side effects such as inflammatory reaction. Therefore, it is necessary to develop novel photothermal antibacterial system with high biocompatibility and safety to fight bacterial infection. Combined antibacterial strategy can effectively solve this problem. In this work, mesoporous carbon nanospheres (MCN) were prepared and oxidized by the mixed acid to obtain carboxyl-rich oxidized mesoporous carbon nanospheres (OMCN) with high biocompatibility and photothermal properties. Then, OMCN- PHMB nano-antibacterial platform was obtained by grafting the antimicrobial agent poly(hexamethylene biguanide)hydrochlo- ride (PHMB) onto the surface of OMCN with amide covalently. The photothermal properties of the system were evaluated and the results showed that the photothermal performance of OMCN had a good dependence on the concentration and power density of near-infrared light. Similar to the OMCN, the obtained OMCN-PHMB exhibited excellent performance of photothermal controllability and photothermal stability. In vivo and in vitro antibacterial experiments showed that the therapeutic effect of OMCN-PHMB under 808 nm laser irradiation was significantly better than that of other treatment groups under the single mode, which confirmed the excellent antibacterial effect of OMCN-PHMB combined with photothermal therapy. In addition, histological analysis showed that the nanoplatform had no significant toxicity to the major organs of mice, indicating OMCN-PHMB had a high biocompatibility. To sum up, the photothermal synergistic nano-antibacterial platform constructed in this study is expected to serve as a safe and controllable biomedical platform to combat various diseases caused by bacterial infection, providing a new antibacterial strategy for clinical treatment of bacterial infection diseases.