States in adherent platelet morphology and the processing of adsorbed protein on biomaterials

This study evaluates the range of adherent platelet morphologies and their relationship to preadsorbed protein. Fluorescently labelled protein was used so changes in its distribution could be followed along with morphological states assessed with modulation-contrast microscopy. Our particular concern was with the quantitative relationship between the platelet and the fluorescent image. The findings from this study continue to support the idea that platelets do interact with adsorbed protein so that protein redistribution occurs and that thrombin accelerates this. Evidence is also presented to support platelet shrinkage, membrane vesicle formation and destruction as a result of thrombin. The shrinking of adherent platelets causes areas free of pre-adsorbed protein to be exposed. This process will be important determining the nature of the substrate available to cells contacting surfaces along with other adsorbed protein-related processes, e.g. reversible adsorption and post-adsorptive transitions.