School of Life Sciences, Ludong University, Yantai 264025, China.
School of Life Sciences, Ludong University, Yantai 264025, China.
Colloids Surf B Biointerfaces. 2023 Apr;224:113207. doi: 10.1016/j.colsurfb.2023.113207. Epub 2023 Feb 12.
A new type of vancomycin (Van)-modified carbon nanodots (CNDs@Van) with pH-responsive surface charge switchable activity was successfully developed by covalently cross-linking Van on the surface of carbon nanodots (CNDs). Polymeric Van was formed on the surface of CNDs by covalent modification, which enhanced the targeted binding of CNDs@Van to vancomycin-resistant enterococci (VRE) biofilms and effectively reduced the carboxyl groups on the surface of CNDs to achieve pH-responsive surface charge switching. Most importantly, CNDs@Van was free at pH 7.4, but assembled at pH 5.5 owing to surface charge switching from negative to zero, resulting in remarkably enhanced near-infrared (NIR) absorption and photothermal properties. CNDs@Van exhibited good biocompatibility, low cytotoxicity, and weak hemolytic effects under physiological conditions (pH 7.4). Regarding targeted binding to VRE bacteria, CNDs@Van self-assembled in a weakly acidic environment (pH 5.5) generated by VRE biofilms, giving enhanced photokilling effects in in vitro and in vivo assays. Therefore, potentially, CNDs@Van can be used as a novel antimicrobial agent against VRE bacterial infections and their biofilms.
成功制备了一种新型的万古霉素（Van）修饰的碳纳米点（CNDs@Van），其表面电荷具有 pH 响应型开关活性。通过将 Van 共价交联到碳纳米点（CNDs）表面，制备了具有聚合 Van 的 CNDs@Van，这增强了 CNDs@Van 对万古霉素耐药肠球菌（VRE）生物膜的靶向结合能力，并有效减少了 CNDs 表面的羧基基团，从而实现了 pH 响应型表面电荷转换。最重要的是，在 pH 7.4 时，CNDs@Van 是游离的，但在 pH 5.5 时由于表面电荷从负到零的转换而发生组装，从而导致近红外（NIR）吸收和光热性能显著增强。在生理条件（pH 7.4）下，CNDs@Van 表现出良好的生物相容性、低细胞毒性和弱溶血作用。在针对 VRE 细菌的靶向结合方面，CNDs@Van 在由 VRE 生物膜产生的弱酸性环境（pH 5.5）中自组装，在体外和体内实验中产生了增强的光杀伤效果。因此，CNDs@Van 有望作为一种新型的抗 VRE 细菌感染及其生物膜的抗菌剂。
