Departmental Seminar

Hindering biofilm formation using topography

Dr William Ducker
Virginia Tech

A biofilm is a three-dimensional collection of microbial cells that is usually held together in an excreted polymeric matrix. One’s attitude to a biofilm generally depends on who you are. Bacteria find this state to be very useful for survival because they are much less susceptible to environmental pressures such as fluid flow and antibiotics. Vegemite manufacturers sometimes find the state desirable. But for people who have medical implants such as catheters, a biofilm infection is undesirable because biofilms are a leading cause of
morbidity and mortality. Hospital acquired infections are the 4th leading cause of death in the United States, and 65% of these infections are associated with implants. One solution to the problem is to make surface coatings that prevent or hinder biofilm formation. I believe that this is a significant opportunity for surface chemists to make contributions to medicine.

In this talk I will discuss our efforts to hinder the formation of biofilms by coating solids with a film that has a topography that is unattractive to bacterial cells. Our focus to date has been on the pathogenic bacterium,
Pseudomonas aeruginosa, and on topography that is created from close packed spheres (a colloidal crystal) that have dimensions commensurate with the bacterium, about 1 μm. Our results show a reduction in viable
cells by about 99%. A similar effect is found for the yeast, Candida albicans. Colloidal crystals are easy and inexpensive to prepare, and we anticipate that that their implementation should be a cost-effective adjunct to the use of chemical antifouling agents, chemical agents, and antibiotic treatments.

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