Varadarajan Ramaswami

Synthesis, Characterization, and Calorimetric Studies of a Series of Novel Bioconjugates for Selective Targeting of Microbubbles to GPIIbIIIa Receptors on Vascular Thrombi

Bioconjugate ligands have been used in our laboratory to target microbubbles to glycoprotein receptors for both diagnostic and therapeutic purposes. The purpose of the bioconjugates (Figure 1) are to: 1) anchor the molecule into the microbubble membrane, 2) provide overall flexibility for the ligand to “find” its target [1], and 3) provide a ligand selective for certain receptors [2]. However, in order for ligands to effectively direct the entire microbubble to a selective receptor, the bioconjugate must remain inserted into the microbubble membrane. Failure to do so could result in “free” bioconjugates acting as competitive receptor antagonists to microbubble or liposome binding. We have thus conducted a calorimetric study to determine the efficiency of insertion of a series of bioconjugates varying only in hydrocarbon tail length.