Magnetic Nanoliposomes as in Situ Microbubble Bombers for Multimodality Image-Guided Cancer Theranostics

Nanosized drug delivery systems have offered promising approaches for cancer theranostics. However, few are effective to simultaneously maximize tumor-specific uptake, imaging, and therapy in a single nanoplatform. Here, we report a simple yet stimuli-responsive anethole dithiolethione (ADT)-loaded magnetic nanoliposome (AML) delivery system, which consists of ADT, hydrogen sulfide (H2S) pro-drug, doped in the lipid bilayer, and superparamagnetic nanoparticles encapsulated inside. HepG2 cells could be effectively bombed after 6 h co-incubation with AMLs. For in vivo applications, after preferentially targeting the tumor tissue when spatiotemporally navigated by an external magnetic field, the nanoscaled AMLs can intratumorally convert to microsized H2S bubbles. This dynamic process can be monitored by magnetic resonance and ultrasound dual modal imaging. Importantly, the intratumoral generated H2S bubbles imaged by real-time ultrasound imaging first can bomb to ablate the tumor tissue when exposed to higher acoustic intensity; then as gasotransmitters, intratumoral generated high-concentration H2S molecules can diffuse into the inner tumor regions to further have a synergetic antitumor effect. After 7-day follow-up observation, AMLs with magnetic field treatments have indicated extremely significantly higher inhibitions of tumor growth. Therefore, such elaborately designed intratumoral conversion of nanostructures to microstructures has exhibited an improved anticancer efficacy, which may be promising for multimodal image-guided accurate cancer therapy.