Study on ultrasound exposure conditions for sonoporation using drug-loaded microbubbles

Abstract

We have been studying sonoporation that promotes drug and gene delivery using ultrasound exposure in the presence of microbubbles. A sonoporation technique that utilizes drug-loaded microbubbles for efficient deliver is widely studied; however, their results showed low transduction rates of the technique. In this study, sonoporation phenomena under three types of exposure condition (continuous, repetitive, pulse) were observed in the presence of fluoresce dye-loaded microbubbles adjacent to cells using confocal microscopy. The results showed that different types of ultrasound exposure induce different types of membrane damage; however, the transduction was achieved only in one cell (3%), which was induced by exposure to pulsed ultrasound. In other cells, adhesion of the dye on cell membrane was frequently observed, suggesting that adhesion of bubble shell lipid to the cell bilayer lipid prevents the dye from transduction into cells. This suggests possibility for improving transduction rates by controlling affinity of microbubbles to cells.