Zhu Zan, Bao Liang, Pestov Dmitry, Xu Ping, Wang Wei-Ning
Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23219, USA.
Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA 23298, USA.
Chem Eng J. 2023 Feb;453(Pt 2). doi: 10.1016/j.cej.2022.139956. Epub 2022 Oct 22.
Photocatalytic oxidative disinfection (POD) towards pathogenic bacteria has become a popular approach in public health due to its environmentally friendly antimicrobial capabilities. However, this approach is still limited by inherent fast electron-hole recombination within photocatalysts and poor interactions between bacterial cells and photogenerated reactive oxygen species (ROS) at the biointerface. Particularly, those ROS with extremely short migration distances cannot reach the bacterial cells before they deteriorate into less potent or neutral species, resulting in reduced antibacterial activities. By far, these phenomena are still poorly understood. Inspired by the fact that bacterial cells are negatively charged, we rationally designed a photocatalyst (, g-CN/MIL-125-NH) by coating a layer of positively charged quaternary ammonium compound (QAC) polymer onto the surface to enhance its affinity towards bacterial cells electrostatic attractions. This surface-modulated photocatalyst is denoted as QAC@-CN/MIL-125-NH. The visualization and quantification of the electrostatic interactions between the bacterial cells and the QAC@-CN/MIL-125-NH photocatalyst were conducted using a confocal laser scanning microscope and atomic force microscope, respectively. The results showed that the positively charged QAC layer did promote the bacteria-photocatalyst contact electrostatic attractions. Due to the cooperative effects of bacterial cell adhesion and ROS generation, the POD performance of the photocatalyst is significantly enhanced. Notably, the photocatalyst achieves 3.20 logs of inactivation efficiency for within 60 min under visible light irradiation. This work provides insights into a mechanistic understanding of bacterial adhesion and disinfection at the biointerface and sheds light on rational photocatalyst design with surface charge modulation for antibacterial applications.
光催化氧化消毒（POD）针对病原菌已成为公共卫生领域一种受欢迎的方法，因为其具有环境友好的抗菌能力。然而，这种方法仍然受到光催化剂内部固有的快速电子 - 空穴复合以及生物界面处细菌细胞与光生活性氧（ROS）之间不良相互作用的限制。特别是，那些迁移距离极短的ROS在降解为效力较低或中性的物种之前无法到达细菌细胞，导致抗菌活性降低。到目前为止，这些现象仍然知之甚少。受细菌细胞带负电荷这一事实的启发，我们通过在表面涂覆一层带正电荷的季铵化合物（QAC）聚合物来合理设计一种光催化剂（，g-CN/MIL-125-NH），以增强其对细菌细胞的亲和力——静电吸引力。这种表面调制的光催化剂被表示为QAC@-CN/MIL-125-NH。分别使用共聚焦激光扫描显微镜和原子力显微镜对细菌细胞与QAC@-CN/MIL-125-NH光催化剂之间的静电相互作用进行了可视化和定量分析。结果表明，带正电荷的QAC层确实通过静电吸引力促进了细菌 - 光催化剂的接触。由于细菌细胞粘附和ROS生成的协同作用，光催化剂的POD性能显著增强。值得注意的是，该光催化剂在可见光照射下60分钟内对达到了3.20个对数的灭活效率。这项工作为生物界面处细菌粘附和消毒的机理理解提供了见解，并为用于抗菌应用的具有表面电荷调制的合理光催化剂设计提供了启示。
