Preparation and evaluation of glycyrrhetinic acid-modified and honokiol-loaded acoustic nanodroplets for targeted tumor imaging and therapy with low-boiling-point phase-change perfluorocarbon.

In this study, a multi-functional drug delivery system, which combines targeted tumor treatment with glycyrrhetinic acid-modified nanodroplets and ultrasound imaging with low-boiling-point phase-change perfluorocarbon, was proposed and validated. The obtained nanodroplets were spherical in shape with an average size of 324.8 ± 183.7 nm and a negative zeta-potential. Low-intensity focused ultrasound (LIFU) was introduced to perform targeted US imaging via acoustic droplet vaporization (ADV) both in vitro and in vivo. The in vitro cytotoxicity and cellular uptake studies conducted on HepG2 cells demonstrated that nanodroplets modified with glycyrrhetinic acid enhanced the selective delivery to cells expressing high levels of glycyrrhetinic acid receptors. Moreover, the glycyrrhetinic acid-modified nanodroplets showed significant antitumor efficacy in HepG2 cell-bearing mice with the assistance of both passive targeting via the EPR effects and active targeting ability of glycyrrhetinic acid. In conclusion, our fabricated multi-functional nanodroplets possess targeted antitumor activity and simultaneous US imaging, providing high potential for targeted tumor theranostics.