INTERACTION OF RGD LIPOSOMES WITH PLATELETS

The interactions of platelets and liposomes with the tripeptide argini ne-glycine-aspartic acid (RGD) as a surface ligand (RGD liposomes) wer e 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 aque ous contents of RGD liposomes with platelets is approximately 4-9 time s and 3-4 times greater than that for unlabeled liposomes, respectivel y. Measurements of the cytoplasmic free Ca2+ concentration in platelet s, [Ca2+](i), show that the RGD liposomes have little effect on [Ca2+] (i). (C) 1996 Academic Press, Inc.