Interaction of RGD liposomes with platelets.

The interactions of platelets and liposomes with the tripeptide arginine-glycine-aspartic acid (RGD) as a surface ligand (RGD liposomes) were studied. The results suggest that the presence of the RGD ligand on the liposomes results in receptor-mediated mixing of lipid and aqueous contents of the liposomes and platelets. Mixing of the lipid and aqueous contents of RGD liposomes with platelets is approximately 4-9 times and 3-4 times greater than that for unlabeled liposomes, respectively. Measurements of the cytoplasmic free Ca2+ concentration in platelets, [Ca2+]i, show that the RGD liposomes have little effect on [Ca2+]i.