Effect of Pretrapping of Microbubbles in Sonoporation Using N-Isopropylacrylamide Gel Flow Channel Phantom

Abstract

It is considered that sonoporation, which produces small pores through a cell membrane, is a sophisticated tool for improving the efficacy of ultrasonic-wave-irradiated drug delivery systems. However, neither the precise mechanism of pore production nor the optimum conditions of insonation have been clarified yet. In this study, the microscopic observation of micron size hollows produced on the wall of an optical transparent gel by bubble cavitation is performed in order to evaluate sonoporation. As a gel phantom, we adopted N -isopropylacrylamide (NIPA) gel, which has almost the same acoustic properties as soft tissue and is optically transparent below the metastasis temperature. Using the gel phantom, the effect of the pretrapping of microbubbles, which is carried out immediately before irradiating a high-intensity ultrasonic wave to prepare the bubble conditions required for sonoporation, is evaluated.