Targeting vascular endothelium with avidin microbubbles

Targeting microbubbles (MBs) to specific vascular beds enables contrast ultrasound to be used for molecular imaging. There are several methods for attaching targeting moieties to the surface of MBs. In the present study, we demonstrate that avidin (Av) can be incorporated into the shelf of perfluorocarbon -exposed sonicated dextrose albumin (PESDA) MBs (Av-PESDA-MBs) and serve as an anchor that links Av-PESDA-MBs to biotinylated monoclonal antibodies (mAbs). This novel linking strategy was used to conjugate Av-PESDA-MBs to mAbs specific for endoglin (CD105) or a control TgG. MBs targeted to CD105 specifically bound to endothelial cells, but not to fibroblasts, in vitro but Av-PESDA-MBs conjugated with the control IgG did not specifically target either cell type. We conclude that Av-PESDA-MBs represent a novel and attractive tool to conjugate MRs with biotinylated mAbs for the purposes of vascular targeting and molecular imaging. (E-mail: rolf.brekken@utsouthwestern.edu) (c) 2005 World Federation for Ultrasound in Medicine & Biology.