ABSTRACT
PurposeTo develop a novel RGD microbubbles (RGD-MBs) and to evaluate the targeted binding effect with endothelial cells in vitro.Materials and MethodsThe RGD peptide was coated onto the microbubbles through biotin-avidin linkage including 10 μg/ml and 30 μg/ml groups. The microbubbles not carrying RGD peptide were obtained as negative control. Blocking studies were performed with pre-incubation of the cells with RGD peptide for 2 hours. The microbubbleswere characterized by Accusizer 780 and optical microscope. The binding specificity of RGD-MBs withανβ3-expressing mouse endothelial cells was determined with competitive inhibition experiments in vitro. The attachment study was performed using parallel plate flow chamber to investigate the dynamic adhesion on endothelial cells at various shear stresses.ResultsThe RGD-MBs had an average diameter of (4.09±0.07) μm. The binding RGD-MBs per cell were 2.98±0.35 for 10 μg/ml RGD and 1.78±0.23 for 30 μg/ml RGD. RGD-MBs binding to mouse endothelial cells decreased 54.64% and 67.00% in the presence of RGD peptide at a concentration of 10 μg/ml and 30 μg/ml respectively. When the shear stress was under 1.5 dyne/cm2, the accumulation rate was increased with the increase of shear stress (P1.5 dyne/cm2 (P<0.05). Conclusion The RGD-MBs can specifically bind to endothelial cells, indicating its usefulness as ultrasonic molecular probe in monitoring integrinανβ3 expression during tumor angiogenesis, and is potentially valuable for in tumor early-staging and prognosis.