Poortinga AT, Bos R, Busscher HJ
Department of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV, Groningen, The Netherlands
Colloids Surf B Biointerfaces. 2001 Feb 1;20(2):105-117. doi: 10.1016/s0927-7765(00)00182-x.
Deposition to glass of Streptococcus salivarius HB-C12 and Staphylococcus epidermidis 3399 in a parallel plate flow chamber has been studied as a function of ionic strength. Electrophoretic mobility measurements revealed that S. epidermidis 3399 possesses a thick ion-penetrable layer, probably associated with its encapsulation, while S. salivarius HB-C12 has an ion-impenetrable surface. Streaming potential measurements indicated that also the glass surface was covered with a relatively thin, ion-penetrable layer. Theoretical initial deposition rates of both strains to glass were obtained by numerically solving the convective-diffusion equation, while accounting for the ion-penetrability of the interacting surfaces. Experimentally, the initial deposition rate of the ion-penetrable strain S. epidermidis 3399 was found to be higher and less dependent on ionic strength than of the ion-impenetrable S. salivarius HB-C12, in accordance with theoretical expectations. Agreement between theoretical and experimental deposition rates could be obtained when glass was considered ion-penetrable when interacting with the ion-penetrable organism S. epidermidis 3399, while glass behaved as an ion-impenetrable surface when interacting with the ion-impenetrable S. salivarius HB-C12. Probably, interaction with an ion-impenetrable strain drives the diffuse double layer charges into the limited volume of the thin ion-penetrable layer on the glass, readily filling it up and making it appear ion-impenetrable. During interaction of glass with another ion-penetrable surface, as of S. epidermidis 3399, diffuse double layer charges move into both ion-penetrable surfaces, resulting in a much lower mobile charge density in the ion-penetrable layer on the glass which consequently continues to behave as ion-penetrable.
在平行平板流动腔中，研究了唾液链球菌HB - C12和表皮葡萄球菌3399在玻璃上的沉积情况与离子强度的关系。电泳迁移率测量表明，表皮葡萄球菌3399具有一层较厚的离子可渗透层，可能与其包膜有关，而唾液链球菌HB - C12具有离子不可渗透的表面。流动电势测量表明，玻璃表面也覆盖有一层相对较薄的离子可渗透层。通过数值求解对流扩散方程，同时考虑相互作用表面的离子可渗透性，得到了两种菌株在玻璃上的理论初始沉积速率。实验发现，与离子不可渗透的唾液链球菌HB - C12相比，离子可渗透的表皮葡萄球菌3399的初始沉积速率更高，且对离子强度的依赖性更小，这与理论预期一致。当认为玻璃与离子可渗透的表皮葡萄球菌3399相互作用时是离子可渗透的，而与离子不可渗透的唾液链球菌HB - C12相互作用时玻璃表现为离子不可渗透表面时，理论沉积速率与实验沉积速率之间可以达成一致。可能是与离子不可渗透菌株的相互作用将扩散双电层电荷驱入玻璃上薄离子可渗透层的有限体积中，使其容易充满并显得离子不可渗透。在玻璃与另一个离子可渗透表面（如表皮葡萄球菌3399）相互作用时，扩散双电层电荷会进入两个离子可渗透表面，导致玻璃上离子可渗透层中的移动电荷密度低得多，因此该层继续表现为离子可渗透。
