Initial bacterial retention on polydimethylsiloxane of various stiffnesses: The relevance of modulus (mis)match

Initial retention of the bacterium Escherichia coli on model poly(dimethylsiloxane) (PDMS) surfaces was studied as a function substrate bulk and surface mechanical stiffness values. Our reference PDMS system designed such that out parameters govern bacterial adhesion only systematically varied. This achieved by varying crosslinking density PDMS. Following crosslinking, we performed Soxhlet extraction non-crosslinked, free chains to rule their effect response. Bulk moduli were assessed dynamic analysis at 1 rad sec?1 frequency values obtained ranged between 0.03 1.8 MPa. The increase in crosslink resulted increasing modulus, measured atomic force microscopy, with ranging 0.7 9 number bacteria retained then assessed. We observed decreasing trend both stiffnesses down limit corresponding Young’s modulus cell surface. For higher than this threshold, remained constant. tentatively explain observation considering conformal overlay material surfaces.