Mimotope receptors and inhibitors employ peptide mimics that mimic the shape and function of natural receptors and ligands, thus providing synthetic binding sites for ligands and receptors. Receptor mimics can be attached to carriers, such as liposomes, to act as synthetic platelets, for example, by providing binding sites for binding to other (natural or synthetic) platelets or to the endothelium. Synthetic platelets would have virtually limitless shelf life and would not require disease screening prior to transfusion, thereby providing a solution to the perpetual platelet shortages, as well as the safety and storage issues associated with natural blood platelets. Mimotope inhibitors (either free-molecule receptors or ligands) can act as antithrombotics by inhibiting platelet-platelet or platelet-endothelium interactions. Ligand mimics are preferably D-peptides that resist proteolytic degradation. Furthermore, these ligand mimics can also be attached to carriers for resisting excretion, thus forming the basis for a new class of antithrombotic drugs.