Organic-Inorganic Hybrid Hollow Mesoporous Organosilica Nanoparticles for Efficient Ultrasound-Based Imaging and Controlled Drug Release

A novel anticancer drug delivery system with contrast‐enhanced ultrasound‐imaging performance was synthesized by a typical hard‐templating method using monodispersed silica nanoparticles as the templates, which was based on unique molecularly organic/inorganic hybrid hollow periodic mesoporous organosilicas (HPMOs). The highly dispersed HPMOs show the uniform spherical morphology, large hollow interior, and well‐defined mesoporous structures, which are very beneficial for ultrasound‐based theranostics. The obtained HPMOs exhibit excellent performances in contrast‐enhanced ultrasonography both in vitro and in vivo and can be used for the real‐time determination of the progress of lesion tissues during the chemotherapeutic process. Importantly, hydrophobic paclitaxel‐ (PTX‐) loaded HPMOs combined with ultrasound irradiation show fast ultrasound responsiveness for controlled drug release and higher in vitro and in vivo tumor inhibition rates compared with free PTX and PTX‐loaded HPMOs, which is due to the enhanced ultrasound‐triggered drug release and ultrasound‐induced cavitation effect. Therefore, the achieved novel HPMOs‐based nanoparticle systems will find broad application potentials in clinically ultrasound‐based imaging and auxiliary tumor chemotherapy.