van Merode Annet E J, Duval Jérôme F L, van der Mei Henny C, Busscher Henk J, Krom Bastiaan P
Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands.
Colloids Surf B Biointerfaces. 2008 Jul 15;64(2):302-6. doi: 10.1016/j.colsurfb.2008.02.004. Epub 2008 Feb 15.
Initial adhesion is a determinant in the development of microbial biofilms. It is influenced, amongst others, by the surface hydrophobicity and the electrostatic characteristics of the substratum and adhering organisms. Enterococcus faecalis strains, grown in pure cultures, generally display subpopulations with different electrokinetic features, reflected in a bimodal electrophoretic mobility distribution. Here, the initial adhesion kinetics of five heterogeneous and five homogeneous E. faecalis strains were followed in a parallel-plate flow chamber. After 4h of flow, heterogeneous strains adhered in significantly higher numbers than homogeneous strains (7.3 x 10(6) and 1.9 x 10(6)cm(-2), respectively), but the initial deposition rates were not significantly influenced (740 and 600 cm(-2)s(-1), respectively). Apparently, initial deposition of bacteria is mainly governed by attractive Lifshitz-Van der Waals forces that overwhelm the electrostatic repulsion energy barrier, thus resulting in similar initial deposition rates for the various bacterial populations investigated. In contrast, during later stages of adhesion, bacteria in heterogeneous cultures likely experience a lower electrostatic repulsion from already adhering bacteria than bacteria in homogeneous cultures, thus allowing a closer proximity of the bacteria with respect to each other, which ultimately leads to increased adhesion after 4 h.
初始黏附是微生物生物膜形成过程中的一个决定因素。它受到多种因素的影响，其中包括基质和黏附微生物的表面疏水性以及静电特性。在纯培养物中生长的粪肠球菌菌株通常表现出具有不同电动特性的亚群，这反映在双峰电泳迁移率分布上。在此，在平行板流动腔中追踪了五种异质性和五种同质性粪肠球菌菌株的初始黏附动力学。流动4小时后，异质性菌株的黏附数量明显高于同质性菌株（分别为7.3×10⁶和1.9×10⁶ cm⁻²），但初始沉积速率没有受到显著影响（分别为740和600 cm⁻² s⁻¹）。显然，细菌的初始沉积主要受吸引力的里夫希茨 - 范德华力支配，这种力克服了静电排斥能垒，因此对于所研究的各种细菌群体而言产生了相似的初始沉积速率。相比之下，在黏附的后期阶段，异质性培养物中的细菌可能比同质性培养物中的细菌受到来自已黏附细菌的静电排斥更低，从而使得细菌彼此之间能够更紧密地靠近，这最终导致在4小时后黏附增加。
