The effect of surface topography on the retention of microorganisms

This paper reviews the effect of substratum topography on microbial retention. It is generally acknowledged that an increased substratum surface roughness affects the retention of microorganisms on that surface. However, this premise is only valid for certain feature dimensions: if the features are considerably larger than the microbial cells, then retention is not significant; if the features are of microbial dimensions, then retention may become a problem. Surface features of nano-dimensions have been shown to affect cell behaviour and increase microbial retention. If features are linear (e.g., scratches), then cocci may be trapped, but rod shaped bacteria may not-depending on cell alignment, and binding energy within or across surface features. This is also true for more well separated features, such as pits. Much work has been carried out on the effect of microbial retention on surfaces with randomly sized, orientated and shaped features. To gain a better understanding of the effect of surface roughness on microbial retention it is essential that surfaces with defined features, hydrophobicities and chemistries are used. Using this knowledge, the development of more easily cleanable, hygienic surfaces is possible.