Sonodynamic
therapy (SDT) utilizes ultrasonic excitation of a sensitizer to generate
reactive oxygen species (ROS) to destroy
tumor. Two dimensional (2D)
black phosphorus (BP) is an emerging sonosensitizer that can promote ROS production to be used in SDT but it alone lacks active targeting effect and showed low
therapy efficiency. In this study, a stable dispersion of integrated micro-nanoplatform consisting of BP nanosheets loaded and Fe3O4 nanoparticles (NPs) connected
microbubbles was introduced for ultrasound imaging guided and magnetic field directed precision SDT of
breast cancer. The targeted ultrasound imaging at 18 MHz and efficient SDT effects at 1 MHz were demonstrated both in-vitro and in-vivo on the
breast cancer. The magnetic
microbubbles targeted deliver BP nanosheets to the
tumor site under magnetic navigation and increased the uptake of BP nanosheets by inducing cavitation effect for increased cell membrane permeability via ultrasound targeted
microbubble destruction (UTMD). The mechanism of SDT by magnetic
black phosphorus microbubbles was proposed to be originated from the ROS triggered mitochondria mediated apoptosis by up-regulating the
pro-apoptotic proteins while down-regulating the
anti-apoptotic proteins. In conclusion, the ultrasound
theranostic was realized via the magnetic
black phosphorus microbubbles, which could realize targeting and catalytic sonodynamic
therapy.