Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an 710049, China; Laboratory Center of Stomatology, College of Stomatology, Xi'an Jiaotong University, Xi'an 710049, China; State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi'an Jiaotong University, Xi'an 710049, China.
State Key Laboratory of Electrical Insulation and Power Equipment, Center for Plasma Biomedicine, Xi'an Jiaotong University, Xi'an 710049, China.
J Hazard Mater. 2024 Dec 5;480:135833. doi: 10.1016/j.jhazmat.2024.135833. Epub 2024 Sep 12.
Plasma-activated water (PAW) is a novel antimicrobial agent with negligible toxicity and environmental burden, holding promise as an alternative to chemical disinfectants and antibiotics. In practice, liquid disinfectants are often soaked with cotton materials before further use. Rich in reducing functional groups on the surface, cotton will inevitably react with PAW, leading to the deterioration of PAW's functions. To resolve this issue, this work proposes a new concept of "secondary activation" for retaining and enhancing PAW's bioactivity, i.e., pre-treating cotton with air plasma before soaking PAW. For the first time, we find that the PAW absorbed by raw cotton completely loses its bactericidal effect, while plasma-treated cotton (PTC) restores the disinfection capacity and prolongs its effective duration. This restoration is attributed to the absorption of plasma-generated reactive species by cotton with oxidizing and nitrifying modifications on the fiber surface. Consequently, the concentrations of aqueous species in PAW increase rather than decrease after absorption by PTC. In addition, the PTC after 28-day storage can still enable PAW to achieve a bacterial reduction of ∼3 logs. This work identifies and addresses a crucial limitation in the disinfection application of PAW and elucidates the mechanism underlying PTC production and secondary activation of PAW.
等离子体激活水（PAW）是一种新型的抗菌剂，具有极小的毒性和环境负担，有望替代化学消毒剂和抗生素。在实际应用中，液体消毒剂通常在进一步使用前用棉花材料浸泡。棉花表面富含还原性功能基团，不可避免地会与 PAW 发生反应，导致 PAW 功能恶化。为了解决这个问题，这项工作提出了“二次激活”的新概念，以保持和增强 PAW 的生物活性，即用空气等离子体预先处理棉花，然后再浸泡 PAW。我们首次发现，未经处理的棉花吸收的 PAW 完全丧失了杀菌效果，而经过等离子体处理的棉花（PTC）恢复了消毒能力并延长了有效时间。这种恢复归因于等离子体产生的活性物质被棉花吸收，从而在纤维表面发生氧化和硝化修饰。因此，PTC 吸收 PAW 后，PAW 中的水相物质浓度增加而不是减少。此外，经过 28 天储存的 PTC 仍能使 PAW 实现约 3 个对数的细菌减少。这项工作确定并解决了 PAW 消毒应用中的一个关键限制问题，并阐明了 PTC 产生和 PAW 二次激活的机制。
