Dual targeting improves microbubble contrast agent adhesion to VCAM-1 and P-selectin under flow

• Published in: Journal of controlled release 2009-12, Vol.140 (2), p.100-107
• Main Authors: Ferrante, E.A., Pickard, J.E., Rychak, J., Klibanov, A., Ley, K.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - metabolism; Arteriosclerosis; Atherosclerosis - diagnostic imaging; Atherosclerosis - metabolism; Biological and medical sciences; Biotin - chemistry; Contrast media; Contrast Media - chemistry; Contrast Media - metabolism; Controlled release; Fluorocarbons - chemistry; Fluorocarbons - metabolism; General pharmacology; imaging; Iodine Radioisotopes; Mechanical stimuli; Medical sciences; Mice; Microbubbles; Monoclonal antibodies; Oligosaccharides - chemistry; Oligosaccharides - metabolism; P-selectin; P-Selectin - metabolism; Perfusion; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Phospholipids; Phospholipids - chemistry; Polyethylene; Polyethylene Glycols - chemistry; Protein Binding; Recombinant Proteins - metabolism; Streptavidin - chemistry; Stress, Mechanical; Targeting; Ultrasonography; Ultrasound; Ultrasound contrast; vascular cell adhesion molecule 1; Vascular Cell Adhesion Molecule-1 - metabolism; VCAM-1
• ISSN: 0168-3659; 1873-4995
• DOI: 10.1016/j.jconrel.2009.08.001

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/μl, resulting in 800 and 1200 molecules/µm 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 × 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. Microbubble adhesion efficiency within a parallel plate flow chamber. Attachment efficiency (adherent microbubbles/all microbubbles passing field of view per 45 s) of dual, MVCAM.A(429)-targeted microbubbles and PAA-sLe x microbubbles as a function of shear stress. “*”, p < 0.05 from sLe x microbubbles. “+”, p < 0.05 from MVCAM.A(429) microbubbles. Error bars, SEM for n = 8. [Display omitted]