Superparamagnetic iron oxide/drug complex-embedded droplets for Bi-model imaging and enhanced targeted therapy

Ultrasound-triggered acoustic droplet vaporization (ADV) has been reported as a mechanical and chemical theranostic strategy for tumor treatment. In this study, we incorporated superparamagnetic iron oxide nanoparticles (SPIO NPs) into acoustic droplets to allow both magnetism-assisted targeting and magnetic resonance (MR)-guided ultrasound-triggered ADV. The multi-functionality of these droplets was further increased by co-encapsulation of the chemotherapeutic drug doxorubicin (DOX) and surface conjugation of anti-vascular endothelial growth factor receptor 2 (VEGFR2) antibody. Maximum loading capacities of 7.69 mg SPIO and 1.53 mg DOX per mL were achieved. In vitro and in vivo MR imaging demonstrated the feasibility of dual modal imaging of SPIO-embedded droplets. Live C6 glioma cells was used to demonstrate a 5.4-fold improvement in targeting efficacy by magnetism-assisted targeting of the SPIO-embedded droplets, and effective disruption of cells by insonation-induced ADV, suggesting the potential of developing this system for future clinical applications.