Mechanics of biofilm adhesion to ultra-thick polymer brushes*

Intractable biofilms cause tremendous problems in health and industrial settings. This work explores whether and how fluid-like interfaces conferred by ultra-thick polymer brushes have the potential to limit biofilm adhesion. We explore the hypothesis that the lack of sizable mechanical cues to adhering bacteria prevents the bacteria from entering a biofilm state and hence, limits biofilm formation and attachment to the substrate. While polymer brushes have been used in previous studies to minimize biofilm attachment, the mechanism relied upon the physiochemical properties of densely grafted, antifouling polymers. The giant tunable hyaluronan polymer brushes used in this investigation can be grown to be up to 10-100 times thicker than those previously used and have distinct mechanical properties that alter the physical cues provided to bacteria. In this study, we quantify bacterial adhesion and biofilm state while varying the mechanical properties of the brushes by manipulating their grafting density, growth conditions, and post-growth chemical modification, allowing for the creation of brushes of varying height and stiffness. This study will offer insight into a possible new way to thwart biofilm formation and guidance for the design of future surface coatings.