The effect of topography of polymer surfaces on platelet adhesion

In this study, the effect of surface topography on fibrinogen and platelet adsorption was investigated. High aspect ratio surface features, in the submicron to nanometer range, were constructed on the poly- (lactic-co-glycolic-acid) (PLGA) films. The topographic surfaces were fabricated by solvent-mediated polymer casting on a master template. Fibrinogen adsorption and platelets adhesion on these topographic surfaces were quantified by enzyme linked immunosorbent assay (ELISA) and lactate dehydrogenase (LDH) assay respectively, while the activation of platelets was quantified by flow cytometric analysis using fluorescein isothiocyanate (FITC) tagging. The lowest fibrinogen adsorption amount and platelet activity was observed on surfaces with specific topographical features in the submicron range with a significant reduction in adhesion when compared to the pristine PLGA films. The topographical parameters found to induce low levels of fibrinogen adsorption and platelet response were high aspect ratio structures (>3:1) with reduced interspacing (<200 nm) or high density. The results signify that topographical manipulation of thrombogenic surfaces of biodegradable polymers is a feasible approach for reducing their thrombogenicity.