Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Amherst, Massachusetts 01003, United States.
ACS Appl Mater Interfaces. 2022 Aug 3;14(30):34342-34353. doi: 10.1021/acsami.2c05936. Epub 2022 Jul 20.
Bacteria are keenly sensitive to properties of the surfaces they contact, regulating their ability to form biofilms and initiate infections. This study examines how the presence of flagella, interactions between the cell body and the surface, or motility itself guides the dynamic contact between bacterial cells and a surface in flow, potentially enabling cells to sense physicochemical and mechanical properties of surfaces. This work focuses on a poly(ethylene glycol) biomaterial coating, which does not retain cells. In a comparison of four strains with different flagellar expressions and motilities, cells with substantial run-and-tumble swimming motility exhibited increased flux to the interface (3 times the calculated transport-limited rate which adequately described the non-motile cells), greater proportions of cells engaging in dynamic nanometer-scale surface associations, extended times of contact with the surface, increased probability of return to the surface after escape and, as evidenced by slow velocities during near-surface travel, closer cellular approach. All these metrics, reported here as distributions of cell populations, point to a greater ability of motile cells, compared with nonmotile cells, to interact more closely, forcefully, and for greater periods of time with interfaces in flow. With contact durations of individual cells exceeding 10 s in the window of observation and trends suggesting further interactions beyond the field of view, the dynamic contact of individual cells may approach the minute timescales reported for mechanosensing and other cell recognition pathways. Thus, despite cell translation and the dynamic nature of contact, flow past a surface, even one rendered non-cell arresting by use of an engineered coating, may produce a subpopulation of cells already upregulating virulence factors before they arrest on a downstream surface and formally initiate biofilm formation.
细菌对其接触的表面特性非常敏感，能够调节其形成生物膜和引发感染的能力。本研究探讨了鞭毛的存在、细胞体与表面的相互作用或运动本身如何指导细菌细胞在流动中与表面的动态接触，从而使细胞能够感知表面的物理化学和机械特性。这项工作集中在一种聚乙二醇生物材料涂层上，该涂层不会保留细胞。在比较具有不同鞭毛表达和运动能力的四个菌株时，具有大量跑滚游泳运动能力的细胞表现出向界面的通量增加（是充分描述非运动细胞的计算传输限制速率的 3 倍），更多比例的细胞参与动态纳米级表面关联，与表面接触的时间延长，逃脱后返回表面的可能性增加，并且由于在近表面运动期间的速度较慢，细胞接近度增加。所有这些指标（这里报告为细胞群体的分布）表明，与非运动细胞相比，运动细胞能够更紧密、更有力地与流动中的界面相互作用更长时间。在观察窗口内单个细胞的接触持续时间超过 10 秒，并且趋势表明在视场之外还有进一步的相互作用，单个细胞的动态接触可能接近机械感应和其他细胞识别途径报道的分钟时间尺度。因此，尽管存在细胞平移和接触的动态性质，但即使是使用工程涂层使表面不具有细胞截留能力的流动，也可能会产生一个亚群的细胞，在它们在下游表面上停止并正式开始生物膜形成之前，已经上调了毒力因子。
