(86d) Effects of Microtopographic Patterns On Escherichia Coli Biofilm Formation On Polydimethylsiloxane Surfaces

Biofilms are involved in 80% of human bacterial infections and are up to 1000 times more tolerant to antibiotics than their planktonic counterparts. To better understand the mechanism of bacteria-surface interaction, polydimethylsiloxane (PDMS) surfaces with microtopographic patterns were tested to study the effects of surface topography on bacterial adhesion and biofilm formation. The patterned PDMS surfaces were prepared by transferring complementary surface topography from a silicon wafer etched via photolithography to introduce 10 µm tall square-shape features. The dimension of protruding square features and the distance between adjacent features were systematically varied. Escherichia coli RP437/pRSH103 (with constitutive expression of red fluorescence protein) was found to preferably attach and form biofilms in valleys between protruding features even when the dimension of plateaus (top of the square features) is considerably larger than valleys. In addition, significant adhesion of E. coli RP437/pRSH103 cells on plateaus was only observed for 20 µm × 20 µm and larger plateaus. These findings suggest that surface topography has significant influence on bacterial biofilm formation and a threshold dimension may be essential for biofilm formation on flat surfaces.