Tang Haiying, Cao Ting, Liang Xuemei, Wang Anfeng, Salley Steven O, McAllister James, Ng K Y Simon
Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, Michigan, USA.
J Biomed Mater Res A. 2009 Feb;88(2):454-63. doi: 10.1002/jbm.a.31788.
Bacterial adhesion and colonization are complicated processes that depend on many factors, including surface chemistry, hydrophobicity, and surface roughness. The contribution of each of these factors has not been fully elucidated because most previous studies used different polymeric surfaces to achieve differences in properties. The objective of this study was to modify hydrophobicity and roughness on one polymeric surface, eliminating the confounding contribution of surface chemistry. Mechanically assembled monolayer (MAM) preparation methods (both one- and two-dimensional) were used to impart different degrees of hydrophobicity on fluoroalkylsilane (FAS)-coated silicone. Surface roughness was varied by casting the silicone to templates prepared with different abrasives. Surface hydrophobicity was determined by contact angle measurement, whereas surface roughness was determined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Bacterial adhesion and colonization were analyzed using a direct colony-counting method and SEM images. Hydrophobicity increased as a function of stretched length or width (Deltax or Deltay); it reached a maximum at Deltax = 60% with one-dimensional MAM and decreased as Deltax further increased to 80 and 100%. The same trend was observed for the two-dimensional MAM. After 12-h incubation, all the FAS/silicone surfaces had significantly reduced adherence of Staphylococcus epidermidis by 42-89%, compared to untreated silicone, and the degree of which is inversely related to surface hydrophobicity. On the other hand, surface roughness had a significant effect on bacterial adhesion and colonization only when the root-mean-square roughness was higher than 200 nm.
细菌黏附和定植是复杂的过程，取决于许多因素，包括表面化学性质、疏水性和表面粗糙度。由于之前的大多数研究使用不同的聚合物表面来实现性质差异，这些因素各自的贡献尚未得到充分阐明。本研究的目的是在一个聚合物表面上改变疏水性和粗糙度，消除表面化学性质的混杂影响。采用机械组装单层（MAM）制备方法（一维和二维）在氟代烷基硅烷（FAS）涂层的硅酮上赋予不同程度的疏水性。通过将硅酮浇铸到用不同磨料制备的模板上来改变表面粗糙度。通过接触角测量确定表面疏水性，而通过扫描电子显微镜（SEM）和原子力显微镜（AFM）确定表面粗糙度。使用直接菌落计数法和SEM图像分析细菌黏附和定植情况。疏水性随着拉伸长度或宽度（Δx或Δy）的增加而增加；在一维MAM中，当Δx = 60%时达到最大值，随着Δx进一步增加到80%和100%而降低。二维MAM也观察到相同趋势。孵育12小时后，与未处理的硅酮相比，所有FAS/硅酮表面上表皮葡萄球菌的黏附显著降低了42 - 89%，且降低程度与表面疏水性呈负相关。另一方面，只有当均方根粗糙度高于200 nm时，表面粗糙度才对细菌黏附和定植有显著影响。
