Dual targeting improves microbubble contrast agent adhesion to VCAM-1 and P-selectin under flow.
To improve ultrasound contrast agents targeted to the adhesion molecules P-selectin and VCAM-1 for the purpose of molecular imaging of atherosclerotic plaques, perfluorocarbon-filled phospholipid microbubble contrast agents were coupled by a polyethylene glycol-biotin-streptavidin bridge with mAb MVCAM.A(429), a sialyl Lewis(x) polymer (PAA-sLe(x)), or both (dual). Approximately three hundred thousand antibody molecules were coupled to the surface of each microbubble. Recombinant mouse P-selectin and/or VCAM-1 coated on flow chambers showed saturation of binding at approximately 15 ng/microl, resulting in 800 and 1200 molecules/microm(2) for P-selectin and VCAM-1, respectively. Dual substrates coated with equal concentrations of P-selectin and VCAM-1 had site densities between 50 and 60% of single substrates. When microbubbles were perfused through flow chambers at 5 x 10(6) microbubbles/ml (wall shear stress from 1.5 to 6 dyn/cm(2)) dual-targeted microbubbles adhered almost twice as efficiently as single-targeted microbubbles at 6 dyn/cm(2). The present study suggests that dual-targeted contrast agents may be useful for atherosclerotic plaque detection at physiologically relevant shear stresses.
Ferrante
E A
EA
Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA. eaf4z@virginia.edu
Pickard
J E
JE
Rychak
J
J
Klibanov
A
A
Ley
K
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism*; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000378:metabolism; D001710:Biotin / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry / Q000378:metabolism*; D005466:Fluorocarbons / Q000737:chemistry / Q000378:metabolism*; D007457:Iodine Radioisotopes; D051379:Mice; D045423:Microbubbles; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D019007:P-Selectin / Q000378:metabolism*; D010477:Perfusion; D010743:Phospholipids / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D000080506:Sialyl Lewis X Antigen; D019809:Streptavidin / Q000737:chemistry; D013314:Stress, Mechanical; D014463:Ultrasonography; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D003287:Contrast Media; D005466:Fluorocarbons; D007457:Iodine Radioisotopes; D009844:Oligosaccharides; D019007:P-Selectin; D010743:Phospholipids; D011994:Recombinant Proteins; D000080506:Sialyl Lewis X Antigen; D019010:Vascular Cell Adhesion Molecule-1; D011092:Polyethylene Glycols; D001710:Biotin; D019809:Streptavidin