Plasma polymer coatings to support mesenchymal stem cell adhesion, growth and differentiation on variable stiffness silicone elastomers

AbstractThe mechanical properties of the underlying substratum have previously been shown to affect a number of cellular processes including locomotion, proliferation and differentiation. Although polyacrylamide is the most studied variable‐stiffness substrate, silicone elastomers offer a more physiologically relevant range of moduli. Here, we employ plasma polymerisation to apply an acid‐containing polymer thin film to silicone elastomer substrates. This simple one‐step surface modification process renders the surfaces hydrophilic and does not require the introduction of extracellular matrix (ECM) proteins commonly used as modification agents to support cell attachment. Contact angle and XPS analysis demonstrates that the coating chemistry is consistent across all of the materials and critically, we show that the addition of this coating does not alter the underlying mechanical properties of the elastomer. The surface modification supports mesenchymal stem cell (MSC) adhesion to a level that is comparable to that seen for tissue culture polystyrene (TCPS). When used as a variable‐stiffness substrate to study cell behaviour we demonstrate that MSC proliferation is unaltered but osteogenic differentiation varies with substrate stiffness.magnified image