Figure 2.

A. Cavitation-based mechanisms by which ultrasound can enhance nanomedicine delivery, including transient disruption through stable cavitation and destructive opening through inertial cavitation (adapted from ¹⁵⁷). B. Co-injection involves simultaneous administration of microbubbles and nanoparticles with ultrasound priming to improve delivery. C-D. Application of microbubble-enhanced focused ultrasound and pre-administered liposomal doxorubicin on rat brains bearing 9L glioma xenografts results in tumor size reduction and prolonged survival compared to doxorubicin only controls (adapted from ⁷⁵). E. Conjugation encompasses both nanoparticle tethering and agent encapsulation to produce a highly co-localized platform for delivery improvement. F. The combination of doxorubicin-loaded microbubbles and ultrasound achieve enhanced therapeutic reduction in DSL6A pancreatic xenograft size compared to drug-loaded bubbles alone (adapted from ⁹⁰). G. In situ microbubble-to-nanoparticle conversion of porphyrin-lipid microbubbles upon ultrasound irradiation leads to enhanced nanoparticle delivery as measured by photoacoustic imaging (adapted from ¹⁵⁶).