School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, China.
Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, Shanghai, 200062, China.
ACS Appl Mater Interfaces. 2022 Jun 8;14(22):25042-25049. doi: 10.1021/acsami.2c00434. Epub 2022 May 31.
Bacterial infection is still a thorny problem threatening human health, and nanozymes offer a promising alternative strategy to combat the health threat posed by bacterial infection. However, the antibacterial efficacies of nanozymes are unsatisfactory because of low catalytic activity of nanozymes and their inability to trap bacteria. Herein, a multifunctional nanozyme, polydopamine (PDA)-modified copper oxide (CuO-PDA) is designed to overcome this challenge. CuO-PDA showed peroxidase-mimicking activity and the catalytic activity was enhanced upon near-infrared (NIR) irradiation. CuO-PDA was negatively charged under neutral or alkaline condition and showed no obvious peroxidase-mimicking activity. On the contrary, the surface charge of CuO-PDA can be switched to positive under acidic conditions, which can target negatively charged bacteria. More interestingly, well-dispersed CuO-PDA can aggregate rapidly under NIR irradiation, which trapped the bacteria and nanozymes together. It was found that shortening the distance between nanozyme and bacteria could improve the antibacterial effect. The obtained CuO-PDA can cause DNA degradation, lipid peroxidation, and biofilm eradication. CuO-PDA showed good antibacterial effect against two kinds of representative bacteria, (Gram-negative) and (Gram-positive). The experiment in vivo further proved favorable antibacterial activity of CuO-PDA nanozyme.
细菌感染仍然是威胁人类健康的棘手问题，纳米酶为应对细菌感染带来的健康威胁提供了一种有前景的替代策略。然而，由于纳米酶的催化活性低，并且无法捕获细菌，因此纳米酶的抗菌效果并不理想。在此，设计了一种多功能纳米酶，即聚多巴胺（PDA）修饰的氧化铜（CuO-PDA），以克服这一挑战。CuO-PDA 具有过氧化物酶模拟活性，并且在近红外（NIR）照射下其催化活性得到增强。在中性或碱性条件下，CuO-PDA 带负电荷，并且没有明显的过氧化物酶模拟活性。相反，在酸性条件下，CuO-PDA 的表面电荷可以转变为正电荷，从而可以靶向带负电荷的细菌。更有趣的是，分散良好的 CuO-PDA 在近红外照射下可以迅速聚集，从而将细菌和纳米酶一起捕获。研究发现，缩短纳米酶与细菌之间的距离可以提高抗菌效果。所得的 CuO-PDA 可以引起 DNA 降解、脂质过氧化和生物膜清除。CuO-PDA 对两种代表性细菌（革兰氏阴性菌）和 （革兰氏阳性菌）表现出良好的抗菌效果。体内实验进一步证明了 CuO-PDA 纳米酶具有良好的抗菌活性。
