Cells and Materials


Platelet structural changes such as spreading and cytoskeletal reorganization that occur upon contact with synthetic surfaces have been well documented . Structural changes such as spreading will vary depending on the substrate involved . Although platelet structural changes following adhesion have been recorded , the cellular mechanisms including changes in intracellular calcium flux underlying these platelet responses are less well understood. In this study, video microscopy was used to image platelet adhesion and spreading while simultaneously imaging intracellular free Ca2+ levels in individual Fura-2 loaded human platelets. This was accomplished using fluorescence video microscopy coupled with video enhanced asymmetric illumination contrast (AIC) to image Ca2+ transients and correlative electron microscopy to image associated structural changes in individual platelets contacting glass and polyvinyl formal , formvar, substrates. Three main points were concluded from this study: 1) Intracellular Ca2+ levels increase with surface- induced activation on either formvar or glass. 2) In partially spread or fully spread platelets, intracellular Ca2+ decreases to a steady state value. 3) Plateletplatelet contact leads to intracellular Ca2+ transients.