(193e) Controlling the Adhesion of Staphylococcus Aureus to Polydimethylsiloxane Biomaterials

Bacterial adhesion and consequent biofilm formation are recurrent problems that lead to infections and death. Antibiotics, the standard but imperfect means of combatting these infections, kill bacteria while also contributing to antibiotic-resistant bacteria. In particular, the growing prevalence of infections caused by methicillin-resistant Staphylococcus aureus (MSRA) has directed our work to better understand the initial adhesion of S. aureus to medically relevant biomaterials and potentially, develop alternative approaches that can be employed to reduce bacterial adhesion. The mechanical properties and chemistry of hydrogels, such as stiffness and hydrophilicity, respectively, have been demonstrated to affect the initial rate of bacterial adhesion to different surfaces. However, more questions remain as to the attachment of microbes to polydimethylsiloxane (PDMS), a common polymeric organosilicon compound used for medical devices and coatings. PDMS was fabricated into gels that had various mechanical properties and concentrations of unreacted oligomers. Material properties of the gels, such as tackiness, viscoelasticity, homogeneity, and hydration, were quantified using rheology, Fourier-transform infrared spectroscopy, and contact angle measurements. To better understand the mechanism of attachment, the adherence of S. aureus ATCC 12600, a genome-sequenced strain, and S. aureus SH1000, a clinically-isolated strain, to the PDMS gels was assessed using a 24 hour assay. This work provides insight into the mechanism of adhesion for S. aureus to PDMS gels and potentially, also how to design bacteria-resistant surfaces for a broad range of applications, including medical implants.