Programmable ultrasound imaging guided theranostic nanodroplet destruction for precision therapy of breast cancer.

Ultrasound-stimulated contrast agents have gained significant attention in the field of tumor treatment as drug delivery systems. However, their limited drug-loading efficiency and the issue of bulky, imprecise release have resulted in inadequate drug concentrations at targeted tissues. Herein, we developed a highly efficient approach for doxorubicin (DOX) precise release at tumor site and real-time feedback via an integrated strategy of "programmable ultrasonic imaging guided accurate nanodroplet destruction for drug release" (PND). We synthesized DOX-loaded nanodroplets (DOX-NDs) with improved loading efficiency (15 %) and smaller size (mean particle size: 358 nm). These DOX-NDs exhibited lower ultrasound activation thresholds (2.46 MPa). By utilizing a single diagnostic transducer for both ultrasound stimulation and imaging guidance, we successfully vaporized the DOX-NDs and released the drug at the tumor site in 4 T1 tumor-bearing mice. Remarkably, the PND group achieved similar tumor remission effects with less than half the dose of DOX required in conventional treatment. Furthermore, the ultrasound-mediated vaporization of DOX-NDs induced tumor cell apoptosis with minimal damage to surrounding normal tissues. In summary, our PND strategy offers a precise and programmable approach for drug delivery and therapy, combining ultrasound imaging guidance. This approach shows great potential in enhancing tumor treatment efficacy while minimizing harm to healthy tissues.