Benmamoun Zachary, Kinard Thomas, Chandar Prem, Jankolovits Joe, Ducker William A
Department of Chemical Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States.
Unilever Research & Development, Trumbull, Connecticut 06611, United States.
Biomacromolecules. 2025 Jun 9;26(6):3322-3330. doi: 10.1021/acs.biomac.4c01706. Epub 2025 May 19.
Cationic antiseptics are deployed in a variety of settings, where salinity ranges from almost pure water to hypertonic salt. Here, we examine how dissolved NaCl affects the antimicrobial action of a model antimicrobial, polydiallyldimethylammonium chloride (PDADMAC) to the bacterium (). Fluorescence microscopy is used to measure the time course of both the adsorption of PDADMAC to and the cell viability. NaCl decreases the density of adsorbed PDADMAC and diminishes its efficacy. At NaCl concentrations at or above 0.15 M, PDADMAC no longer kills bacteria but still prevents reproduction by halting the growth in cell length. Reproduction can be restarted if PDADMAC is removed. Fluorescence depolarization measurements show that PDADMAC rigidifies model membranes, but salt reduces the rigidity. We therefore attribute the halt in cell growth to reversible bridging by the polymer on the cell surface that prevents expansion of the cell membrane.
阳离子防腐剂被应用于各种环境中，这些环境的盐度范围从几乎纯水到高渗盐溶液。在此，我们研究了溶解的氯化钠（NaCl）如何影响一种模型抗菌剂聚二烯丙基二甲基氯化铵（PDADMAC）对细菌（此处原文缺失具体细菌名称）的抗菌作用。荧光显微镜用于测量PDADMAC吸附到细菌上的时间进程以及细胞活力。NaCl降低了吸附的PDADMAC的密度并削弱了其功效。在NaCl浓度达到或高于0.15 M时，PDADMAC不再杀死细菌，但仍通过阻止细胞长度增长来抑制繁殖。如果去除PDADMAC，繁殖可以重新开始。荧光去极化测量表明PDADMAC使模型膜变硬，但盐会降低这种硬度。因此，我们将细胞生长的停滞归因于聚合物在细胞表面的可逆桥连，这种桥连阻止了细胞膜的扩张。
