Bacteria Pattern Spontaneously on Periodic Nanostructure Arrays
Entry by Emily Redston, AP 225, Fall 2011
Work in progress
Bacteria Pattern Spontaneously on Periodic Nanostructure Array by A. I. Hochbaum, J. Aizenberg. Nano Lett. 10, 3717-3721 (2010)
Bacterial biofilms naturally form on many surfaces, usually at the solid-liquid or liquid-air interface. Biofilms are composed of many cells embedded within a polymeric organic matrix. While biofilm formation is a concern for many industries, they are especially harmful in the medical community, where they cause extensive damage by triggering the human immune response, releasing harmful endotoxins and exotoxins, and clogging indwelling catheters. Hospital-acquired, or nosocomial, infections affect roughly 10% of patients in the United States, and they are responsible for nearly 100,000 deaths. These infections are difficult to treat because the biofilm protects the cells from antibiotic attack. Developing biomedical materials that are resistant to biofilm formation has been a hot topic in research since it would significantly reduce the rate of nosocomial infections and the costs associated with treating them.
In this regard, many people have attempted to use surface chemistry to prevent biofilm formation. Unfortunately, persistently bacteria-resistant materials are difficult to achieve using surface chemistry alone. Even if the bacteria are unable to attach to a substrate directly, nonspecific adsorption of proteins or secreted surfactants to the surface eventually masks the underlying chemical functionality.
On the other hand, the effects of topographical features on bacterial adhesion and subsequent biofilm formation are poorly understood. However, recent studies have shown that the behavior of mammalian cells can be manipulated using only spatial and mechanical clues. Biofilms contain a diversity of microbial phenotypes and form spatial patterns through cooperative organization at the macroscopic and microscopic level. They develop anisotropically in response to surrounding environmental factors. Topographical features can influence the arrangement and the resulting behavior of cells on surfaces. Some bacteria rely on physical interactions between neighboring cells for communication. Therefore, disrupting the natural packing arrangement of cells within biofilms may influence some of the cooperative functions of these microbial populations. Following this train of thought, in this paper, the authors present a very exciting, alternative approach to preventing biofilm formation. They show that periodic arrays of high-aspect-ratio nanostructures can direct the large-scale spontaneous patterning behavior of bacteria.