The antimicrobial properties of copper are well-known but maintaining a low oxidation state of Cu in particles is difficult. Herein, antimicrobial Cu_xP particles were synthesized through phosphorization of Cu(OH)₂, to lock copper in its monovalent state (as Cu₃P). We found that the phosphorization could be achieved at temperatures as low as 200°C, with stable surface presence of Cu(I) on the resulting Cu_xP particles. Cu(I) can act as a one-electron reducing agent for molecular oxygen, to generate the highly reactive hydroxyl radical. In this study, Cu_xP displayed antibacterial activities on the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, with minimum inhibitory concentrations of 32 mg/L for the highest temperature particles (350°C) on both model bacteria. The evident membrane damage is consistent with the intended hydroxyl radical bacterial targeting mechanism. Low-temperature Cu_xP, although exhibiting lower antibacterial efficacies than those of the higher temperature variant, still showed competitive growth inhibiting activities when compared to other reported antimicrobial copper-based particles. The present work showcases advancements in particle technology that can lead to the development of a more robust antimicrobial agent, presenting a potent additive for self-disinfection applications.

中文翻译：

---

用于抗菌应用的羟基自由基生成单价铜颗粒

铜的抗菌性能是众所周知的，但很难在颗粒中保持铜的低氧化态。在此，抗菌 Cu _{x P 颗粒通过 Cu(OH) 2}的磷化合成，以将铜锁定在其单价状态（作为 Cu ₃ P）。_{我们发现磷化可以在低至 200°C 的温度下实现，并且在所得 Cu x} P 颗粒上稳定存在 Cu(I) 表面。Cu(I)可以作为分子氧的单电子还原剂，产生高活性的羟基自由基。在这项研究中，Cu _x P 对革兰氏阳性金黄色葡萄球菌和革兰氏阴性大肠杆菌表现出抗菌活性, 对两种模型细菌的最高温度颗粒 (350°C) 的最低抑制浓度为 32 mg/L。明显的膜损伤与预期的羟基自由基细菌靶向机制一致。低温 Cu _x P，虽然表现出比高温变体更低的抗菌功效，但与其他报道的抗菌铜基颗粒相比，仍显示出竞争性的生长抑制活性。目前的工作展示了粒子技术的进步，这些进步可以导致开发更强大的抗菌剂，为自我消毒应用提供有效的添加剂。