Mechanisms controlling increased vascular cell adhesion to nano-structured polymer films

Previous research has shown that increasing the nanometer surface roughness of poly(lactic-co-glycolic acid) (PLGA) films promotes vascular endothelial and smooth muscle cell adhesion. The goal of this in vitro research was to understand the mechanism(s) behind these observed responses. In order to elucidate the adhesive factors for vascular cell adhesion on nano-structured PLGA, substrates of various surface feature dimensions were exposed to serum-containing media overnight. The adsorbed proteins were then desorbed using a stripping buffer and the amount, as well as type, of proteins initially adsorbed were analyzed. Furthermore, cellular adhesion studies were preformed in order to correlate the link between specific protein adsorption and subsequent cellular response. Results showed that nano-structured PLGA adsorbed significantly more vitronectin and fibronectin when compared to conventional PLGA. Additionally, vascular cell adhesion studies demonstrated that both vascular smooth muscle cell and endothelial cell density increased on vitronectin and fibronectin pre-adsorbed onto nano-structured (compared to conventional) PLGA. In combination, these results provide insights into the mechanism(s) of increased vascular cell adhesion on nano-structured PLGA important for tissue engineering applications.