Abstract 358: Development of Antibody-carrying Microbubbles Based on Clinically Available Ultrasound Contrast Agent for Targeted Molecular Imaging
Background and Aim: Although antibody-conjugated microbubbles have enabled molecular ultrasound imaging in the last decade, the attachment of antibodies onto microbubbles is technically difficult. The aim of this study was to examine the feasibility of an antibody-carrying targeted-bubble preparation using commercially available microbubbles, Sonazoid.
Methods and Results: Firstly, we examined whether phosphatidylserine (PS) on the surface of Sonzoid could be detected by means of flow cytometry (FACS) using fluorescein-labeled annexin V, which binds specifically to PS. After conjugation with FITC-labeled annexin V, FITC-positive Sonazoid could be detected by FACS analysis. Secondly, we examined whether PE-labeled streptavidin could be attached to Sonazoid through the intermediation of biotinylated-annexin V. The PE-signal of Sonazoid was markedly enhanced by the avidin-biotin binding method. Finally, we examined whether attachment of Alexa488-labeled, biotinylated-IgG onto Sonazoid could be amplified using a biotinylated-annexin V and avidin-biotin binding method (Figure⇓). Significant amplification of the Alexa488 signal of IgG-attached Sonazoid was accomplished through the intermediation of biotinylated-annxin V and streptavidin.
Conclusion: Our results support the feasibility of an antibody-carrying targeted-bubbles preparation based on a commercially available contrast agent, Sonazoid. Although further study regarding the biological safety and diagnostic utility of targeted-Sonazoid should be examined, this technique of bubble preparation might be applicable for targeted molecular ultrasound imaging in clinical settings.