Yamaguchi Masato, Ma Teng, Tadaki Daisuke, Hirano-Iwata Ayumi, Watanabe Yoshihiko, Kanetaka Hiroyasu, Fujimori Hiroshi, Takemoto Emiko, Niwano Michio
Tohoku Fukushi University, Sendai 989-3201, Japan.
Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai 980-8577, Japan.
Langmuir. 2021 Aug 2. doi: 10.1021/acs.langmuir.1c01578.
We investigated the bactericidal activity of bulk nanobubbles (NBs) using , a model bacterium. Bulk NBs were produced by forcing gas through a porous alumina membrane with an ordered arrangement of nanoscale straight holes in contact with water. NBs with different gas contents, including CO, O, and N, were generated and evaluated for their bactericidal effects. The survival rate of was significantly reduced in a suspension of CO-containing NB (CO-NB water). The N-NB water demonstrated a small amount of bactericidal behavior, but its impact was not as significant as that of CO-NB water. When was retained in O-NB water, the survival rate was even higher than that in pure water (PW). We investigated the generation of reactive oxygen species (ROS) in NB suspensions by electron spin resonance spectroscopy. The main ROS generated in the NB water were hydroxyl radicals and OH·, and the production of ROS was the strongest in CO-NB water, which was consistent with the results of the bactericidal effect measurements. We assumed that NB mediated by ROS would exhibit bactericidal behavior and proposed a kinetic model to explain the retention time variation of the survival rate. The results calculated based on the proposed model matched closely with the experimental results.
我们使用一种模式细菌来研究大量纳米气泡（NBs）的杀菌活性。通过迫使气体通过与水接触的具有纳米级直孔有序排列的多孔氧化铝膜来产生大量纳米气泡。生成了含有不同气体成分（包括一氧化碳、氧气和氮气）的纳米气泡，并评估了它们的杀菌效果。在含一氧化碳纳米气泡（CO-NB水）的悬浮液中，该模式细菌的存活率显著降低。N-NB水表现出少量的杀菌行为，但其影响不如CO-NB水显著。当该模式细菌保留在O-NB水中时，其存活率甚至高于在纯水（PW）中的存活率。我们通过电子自旋共振光谱研究了纳米气泡悬浮液中活性氧（ROS）的产生。纳米气泡水中产生的主要活性氧是羟基自由基和OH·，并且活性氧的产生在CO-NB水中最强，这与杀菌效果测量结果一致。我们假设由活性氧介导的纳米气泡会表现出杀菌行为，并提出了一个动力学模型来解释存活率的保留时间变化。基于所提出模型计算的结果与实验结果密切匹配。
