Department of Physics, University of Texas at Austin, Austin, TX, United States of America.
Center for Nonlinear Dynamics, University of Texas at Austin, Austin, TX, United States of America.
PLoS One. 2020 Jul 28;15(7):e0236599. doi: 10.1371/journal.pone.0236599. eCollection 2020.
The increasing prevalence of carbon nanotubes (CNTs) as components of new functional materials has the unintended consequence of causing increases in CNT concentrations in aqueous environments. Aqueous systems are reservoirs for bacteria, including human and animal pathogens, that can form biofilms. At high concentrations, CNTs have been shown to display biocidal effects; however, at low concentrations, the interaction between CNTs and bacteria is more complicated, and antimicrobial action is highly dependent upon the properties of the CNTs in suspension. Here, impact of low concentrations of multiwalled CNTs (MWCNTs) on the biofilm-forming opportunistic human pathogen Pseudomonas aeruginosa is studied. Using phase contrast and confocal microscopy, flow cytometry, and antibiotic tolerance assays, it is found that sub-lethal concentrations (2 mg/L) of MWCNTs promote aggregation of P. aeruginosa into multicellular clusters. However, the antibiotic tolerance of these "young" bacterial-CNT aggregates is similar to that of CNT-free cultures. Overall, our results indicate that the co-occurrence of MWCNTs and P. aeruginosa in aqueous systems, which promotes the increased number and size of bacterial aggregates, could increase the dose to which humans or animals are exposed.
碳纳米管（CNTs）作为新型功能材料的组成部分，其在环境中的浓度不断增加，这带来了意想不到的后果。水系统是细菌的储存库，包括人类和动物病原体，可以形成生物膜。研究表明，在高浓度下，CNTs 具有杀菌作用；然而，在低浓度下，CNTs 与细菌之间的相互作用更为复杂，抗菌作用高度依赖于悬浮 CNTs 的特性。在这里，研究了低浓度多壁碳纳米管（MWCNTs）对机会性病原体铜绿假单胞菌形成生物膜的影响。通过相差和共聚焦显微镜、流式细胞术和抗生素耐受性测定，发现亚致死浓度（2mg/L）的 MWCNTs 促进了铜绿假单胞菌聚集到多细胞簇中。然而，这些“年轻”细菌-CNT 聚集体的抗生素耐受性与无 CNT 培养物相似。总的来说，我们的结果表明，MWCNTs 和铜绿假单胞菌在水系统中共存，增加了细菌聚集体的数量和大小，可能会增加人类或动物接触的剂量。
