In situ real-time investigation of Staphylococcus aureus on hemisphere-patterned polyurethane films

Surface patterning is a promising approach to prevent bacterial adhesion and biofilm formation without the concerns of antimicrobial resistance. To determine the parameters of a patterned surface that can affect bacterial behavior, a sphere-like coccus (Staphylococcus aureus) was investigated on a series of polyurethane films with ordered hemisphere patterns. The bacterial retention data in a growth medium indicated that the surface patterns significantly decreased bacterial adhesion and proliferation. The most notable effects were observed with the 2 µm-pattern as well as the patterned polycaprolactone and polystyrene films, and the accessible contact area of the polyurethane films, surface wettability, and spatial confinement, did not show an influence. An optical microscope with a modified incubation cell was used for in situ real-time observations of bacterial colonization, proliferation, and migration. Based on appropriate statistical analyses, it was concluded that topographical geometry played a dominant role. In combination with the retention assessment in a nongrowth medium, it was found that pattern-mediated inhibition of biofilm formation was mainly achieved by affecting bacterial proliferation rather than adhesion. This study provides new insight for designing biofilm-resistant biomimetic materials.