In vitro imaging study of E-selectin receptor-targetting ultrasound contrast agent

Abstract

Objective To develop a vulnerable plaque targeting ultrasound contrast agent (UCA) and to evaluate its affinity and imaging performance in vitro. Methods E-selectin receptor-targeting UCA, which conjugated with monoclonal antibody of E-selectin, was prepared with filming-rehydration method and biotin-avidin linkage. The size and distribution of UCA were measured with particle size analyzer, the connectivity condition of microbubbles with E-selectin antibody was also detected with fluorescence analysis. The cytotoxicity from microbubble and ultrasound irradiation was evaluated through cell counting kit-8 (CCK8) assay. The adhesion effect of UCA was assessed after co-incubated with activated mouse endothelial cells (bEnd.3) and compared with that of free antibody intervention group and control group. The imaging performance of UCA at different time points was observed on an ultrasound equipment with a high-frequency transducer. Two-sample t test and one-way analysis of variance were performed to analyze the data. Results E-selectin receptor-targeting UCA was successfully prepared. The cytotoxicity result with CCK8 assay demonstrated the favorable biocompatibility of UCA. The connection amount of UCA on activated bEnd.3 cells ((6.23±0.45) bubbles/cell) was significantly higher than that of the free antibody intervention group ((1.57±0.34) bubbles/cell) and control group ((0.07±0.03) bubbles/cell; F=291.43, P 0.05). Conclusions The prepared E-selectin receptor-targeting UCA has favorable targeting and imaging capabilities. It might be a potentially ultrasound molecular imaging agent for early detection and prognosis evaluation of vulnerable plaque. Key words: E-selectin; Contrast media; Microbubbles; Ultrasonography; Endothelial cells; Mice