Mechano-chemical control of cell behaviour by elastomer templates coated with biomimetic Layer-by-Layer nanofilms

Within the field of biomaterials, the control of cell-surface interactions is generally addressed through surface chemistry modification. In this respect, Layer-by-Layer (LbL) coatings constitute promising versatile tools. Most cells are mechanosensitive, therefore the stiffness of their microenvironment should also be considered as a crucial parameter when designing polymer-based biomaterials. Here, we report on the combination of mechanics and surface chemistry of LbL-treated polydimethylsiloxane substrates of tunable stiffness to control cell behaviour. Biomimetic LbL films consist of poly-l-lysine (PLL) and chondroitin-4-sulfate (CSA). Stiffness, surface chemistry, wettability and topography of bare and LbL-treated polydimethylsiloxane were analysed. We demonstrated that cells adhered and grew up on all the substrates with significant promotive effects of PLL-terminated films and stiffer substrates. Pre-osteoblasts differentiation was enhanced onto PLL-terminated films irrespective of stiffness and onto CSA-terminated films in a mechanical dependent manner. These results open outlooks within the field of bone tissue engineering, as they demonstrate that osteoconductive surfaces can be obtained by combining uncrosslinked biomimetic LbL films and the intrinsic mechanical properties of the substrates, that is, without any commonly used, potentially cytotoxic chemical crosslinking. © 2012 The Royal Society of Chemistry.