Department of Chemical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA; Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA.
Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA.
J Colloid Interface Sci. 2023 Dec 15;652(Pt B):1867-1877. doi: 10.1016/j.jcis.2023.08.136. Epub 2023 Aug 26.
Some very effective antimicrobial coatings exploit copper or cuprous oxide (CuO) as the active agent. The aim of this study is to determine which species is the active antimicrobial - dissolved ions, the CuO solid, or reactive oxygen species. Copper ions were leached from CuO into various solutions and the leachate tested for both dissolved copper and the efficacy in killing Pseudomonas aeruginosa. The concentration of copper species leached from CuO into aqueous solution varied greatly with the composition of the aqueous solution. For a range of solution buffers, killing of P. aeruginosa was highly correlated with the concentration of copper in the leachate. Further, 10 µL bacterial suspension droplets were placed on CuO coatings, with or without a polymer barrier layer, and tested for bacterial kill. Killing occurred without contact between bacterium and solid, demonstrating that contact with CuO is not necessary. We therefore conclude that soluble copper species are the antimicrobial agent, and that the most potent species is Cu. The solid quickly raises and sustains the concentration of soluble copper species near the bacterium. Killing via soluble copper ions rather than contact should allow copper coatings to kill bacteria even when fouled, which is an important practical consideration.
一些非常有效的抗菌涂层利用铜或氧化铜 (CuO) 作为活性物质。本研究旨在确定哪种物质是具有抗菌活性的——溶解的离子、CuO 固体还是活性氧。将氧化铜中的铜离子浸出到各种溶液中，并测试浸出液中溶解铜的含量及其对铜绿假单胞菌的杀菌效果。从氧化铜中浸出到水溶液中的铜物种的浓度随水溶液的组成而有很大差异。对于一系列溶液缓冲液，铜绿假单胞菌的杀灭率与浸出液中铜的浓度高度相关。此外，将 10 μL 细菌悬浮液滴放在 CuO 涂层上，有或没有聚合物阻挡层，并测试其杀菌效果。即使没有细菌和固体之间的接触，也会发生杀菌作用，这表明接触 CuO 不是必需的。因此，我们得出结论，可溶性铜物种是抗菌剂，而最有效的物种是 Cu。固体迅速提高并维持细菌附近可溶性铜物种的浓度。通过可溶性铜离子而不是接触进行杀菌可以使铜涂层即使在受到污染时也能杀死细菌，这是一个重要的实际考虑因素。
