Biofilm-related infections are a class of notoriously difficult to treat healthcare-associated infections that frequently develop on the surface of implanted medical devices. As biofilm formation is a surface-associated phenomenon, understanding how the intrinsic properties of materials affect bacterial adhesion enables the development of structure-property relationships that can guide the future design of infection-resistant materials. Despite lacking visual, auditory, and olfactory perception, bacteria still manage to sense and attach to surfaces. For example, bacteria can detect and differentiate the surface chemistry and topography of surfaces. However, the influence of the stiffness and thickness on bacterial-surface interactions is relatively unknown. In this presentation, I will discuss the effect that the fundamental material properties of polymer hydrogels (chemistry, stiffness, and thickness) have on bacterial adhesion and the surface-associated transport of bacteria. By tuning the mechanical properties of two chemically distinct hydrogels, poly(ethylene glycol) and agar, we determined that, independent of hydrogel chemistry and incubation time, Escherichia coli and Staphylococcus aureus attachment correlated positively to increasing hydrogel stiffness. To further explore the effect that hydrogel stiffness has on bacterial adhesion, we investigated the effect of hydrogel thickness, which elucidated a new depth-dependent component to bacterial adhesion. By decoupling the effect of stiffness and thickness from hydrogel chemistry, we unlocked specific structure-property relationships that can be tailored to control the degree of bacterial adhesion and subsequently biofilm formation. In the final portion of the talk, the development and characterization of a universal surface modification that repels microbes will be discussed. When viewed together, the structure-property relationships and smart fouling-resistant zwitterionic chemistry developed in this work offer alternative approaches to mitigate the risk of bacterial infections without relying on antibiotics.

Mechanical and chemical properties of polymer hydrogels influence bacterial adhesion

255th National Meeting (2018)

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