Magnetic nanoparticle-promoted droplet vaporization for in vivo stimuli-responsive cancer theranostics

Abstract

The development of efficient strategies for in vivo stimuli-responsive cancer treatment and personalized biomedicine is a great challenge. To overcome the critical issues and limitations of traditional protocols using acoustic droplet vaporization and optical droplet vaporization in stimuli-responsive tumor treatment, we herein report a new strategy, magnetic droplet vaporization (MDV), based on nanobiotechnology, for efficient magnetic field-responsive cancer theranostics. Perfluorohexane (PFH)-encapsulated superparamagnetic hollow iron oxide nanoparticles with a high magnetic-thermal energy transfer capability quickly respond to an external alternating current (a.c.) magnetic field to produce thermal energy and raise the temperature of the surrounding tumor tissue. The encapsulated PFH, with a desirable boiling point of ~56 °C, can be vaporized to enhance the performance of ultrasound imaging of tumors, as systematically demonstrated both in vitro and in vivo. The magnetic–thermal energy transfer further ablated and removed tumors in mice tumor xenograft models. This unique MDV principle with high versatility and performance is expected to broaden the biomedical applications of nanotechnology and promote clinical translations of intelligent diagnostic and therapeutic modalities, especially for battling cancer. Hollow iron nanoparticles can enhance both the imaging and complete removal of tumours in live mice using magnetically simulated heat. Ultrasound molecular imaging is one of the safest ways to track cancerous cell growth, but its success depends on producing gas-filled microbubbles that attach to the targeted tissue. As an alternative to optical or acoustic microbubble generators, Yu Chen from the Shanghai Institute of Ceramics, Yuanyi Zheng from Shanghai Sixth People's Hospital and colleagues have used superparamagnetic iron oxide probes with an encapsulated, low-boiling-point gas inside their nanoshells. After injecting the probes into breast cancer cells, the team applied a non-intrusive alternating-current magnetic field. This stimulus generated thermal energy that raised tissue temperature slightly, releasing numerous microbubbles through vapourization. The ultrasound-guided probes could then heat tumours sufficiently to stop regrowth using longer field exposure times. A novel magnetic droplet vaporization strategy was developed for efficient magnetic field-responsive cancer theranostics. Perfluorohexane (PFH)-encapsulated superparamagnetic hollow iron oxide nanoparticles with high magnetic-thermal energy transfer capability quickly respond to external alternating current (a.c.) magnetic field to produce thermal energy and raise the surrounding temperature of tumor tissue. The encapsulated PFH with desirable boiling point of about 56 °C can be vaporized to enhance the ultrasound imaging performance for responsive imaging. Such a magnetic–thermal energy transfer can further completely ablate and remove the tumor against a mice tumor xenograft model.