Langmuir. 2019 May 28;35(21):7035-7042. doi: 10.1021/acs.langmuir.8b03920. Epub 2019 May 13.
Bacterial adhesion is described as a multistep process of interactions between microbes and the substrate, beginning with reversible contact, followed by irreversible adhesion. We explore the influence of substrate zeta potential on adhesion of Mycobacterium smegmatis, a nonpathogenic bacterial model for tuberculosis-causing Mycobacterium tuberculosis and a common foulant of reverse osmosis filtration systems. Substrates having a range of zeta potentials were prepared by coating silica with the polycation, poly(diallyldimethyl ammonium chloride) (pDADMAC), by adjusting the pH of alumina, a pH-responsive material, and by coating silica with a hydrophobic self-assembled monolayer coating of octadecyltrichlorosilane. Our observations using these surfaces demonstrated that adhesion of M. smegmatis increased significantly by more than 200% on the silica-pDADMAC system and more than 300% on alumina substrates, as zeta potential became less negative, and that the variation of pH did not affect adhesion on alumina surfaces. Live and heat-killed bacteria were studied to investigate the contribution of biological response to adhesion with respect to zeta potential. While approximately 60% fewer heat-killed M. smegmatis adhered to pDADMAC-coated silica substrates, the trend of significantly increasing adhesion with less negative zeta potential was still observed. These results show the influence of zeta potential on adhesion of M. smegmatis, which is a separate process from that of the biological response. Across the range of substrate surface chemistries, hydrophobicities, and zeta potentials tested, adhesion of M. smegmatis can primarily be controlled by zeta potential. The bacterial zeta potential was not changed by the various experimental conditions and was -28.3 ± 2.4 mV.
细菌黏附被描述为微生物与基质之间相互作用的多步骤过程，从可逆接触开始，然后是不可逆黏附。我们研究了基质 ζ 电位对耻垢分枝杆菌（一种非致病性结核分枝杆菌模型，也是反渗透过滤系统中常见的污染物）黏附的影响。通过用聚电解质聚二烯丙基二甲基氯化铵（pDADMAC）涂覆二氧化硅、调整 pH 值响应材料氧化铝的 pH 值以及用十八烷基三氯硅烷的疏水自组装单分子层涂覆二氧化硅来制备具有一系列 ζ 电位的基质。我们用这些表面的观察结果表明，随着 ζ 电位变得更负，耻垢分枝杆菌在二氧化硅-pDADMAC 系统上的黏附增加了 200%以上，在氧化铝基质上的黏附增加了 300%以上，而 pH 值的变化并不影响氧化铝表面的黏附。我们研究了活菌和热灭活菌，以研究生物响应相对于 ζ 电位对黏附的贡献。虽然热灭活的耻垢分枝杆菌的黏附减少了约 60%，但仍观察到随着 ζ 电位变得更负而显著增加黏附的趋势。这些结果表明 ζ 电位对耻垢分枝杆菌黏附的影响，这是一个与生物响应分离的过程。在所测试的基质表面化学、疏水性和 ζ 电位范围内，耻垢分枝杆菌的黏附主要可以通过 ζ 电位来控制。细菌 ζ 电位没有因各种实验条件而改变，为-28.3±2.4 mV。
