Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, United States.
School of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong 510225, P. R. China.
Langmuir. 2023 Apr 18;39(15):5426-5439. doi: 10.1021/acs.langmuir.3c00091. Epub 2023 Apr 4.
Bacterial fouling is a persistent problem causing the deterioration and failure of functional surfaces for industrial equipment/components; numerous human, animal, and plant infections/diseases; and energy waste due to the inefficiencies at internal and external geometries of transport systems. This work gains new insights into the effect of surface roughness on bacterial fouling by systematically studying bacterial adhesion on model hydrophobic (methyl-terminated) surfaces with roughness scales spanning from ∼2 nm to ∼390 nm. Additionally, a surface energy integration framework is developed to elucidate the role of surface roughness on the energetics of bacteria and substrate interactions. For a given bacteria type and surface chemistry; the extent of bacterial fouling was found to demonstrate up to a 75-fold variation with surface roughness. For the cases showing hydrophobic wetting behavior, both increased effective surface area with increasing roughness and decreased activation energy with increased surface roughness was concluded to enhance the extent of bacterial adhesion. For the cases of superhydrophobic surfaces, the combination of factors including (i) the surpassing of Laplace pressure force of interstitial air over bacterial adhesive force, (ii) the reduced effective substrate area for bacteria wall due to air gaps to have direct/solid contact, and (iii) the reduction of attractive van der Waals force that holds adhering bacteria on the substrate were summarized to weaken the bacterial adhesion. Overall, this study is significant in the context of designing antifouling coatings and systems as well as explaining variations in bacterial contamination and biofilm formation processes on functional surfaces.
细菌污染是一个长期存在的问题，它会导致工业设备/部件的功能表面恶化和失效；导致许多人类、动物和植物感染/疾病；并由于输送系统内外几何形状的效率低下而导致能源浪费。这项工作通过系统地研究具有从约 2nm 到约 390nm 粗糙度尺度的模型疏水性（甲基封端）表面上的细菌附着，获得了对表面粗糙度对细菌污染影响的新见解。此外，还开发了一个表面能积分框架来阐明表面粗糙度对细菌和基底相互作用的能量学的作用。对于给定的细菌类型和表面化学，发现细菌污染的程度随表面粗糙度的变化高达 75 倍。对于表现出疏水性润湿行为的情况，增加粗糙度会增加有效表面积，增加粗糙度会降低活化能，这两个因素都被认为会增强细菌附着的程度。对于超疏水表面的情况，包括以下因素的综合作用：（i）间隙空气中的 Laplace 压力超过细菌附着力，（ii）由于气隙使细菌壁与基底直接/固体接触而减少有效基底面积，以及（iii）减少将附着细菌固定在基底上的吸引力范德华力，都被总结为削弱细菌附着。总的来说，这项研究在设计抗污染涂层和系统以及解释功能表面上细菌污染和生物膜形成过程的变化方面具有重要意义。
