Facile synthesis of PEGylated dendritic polyurethane as unimolecular micelles for ultrasound-triggered localized drug delivery

The ultrasound-mediated approach has attracted attention for enhanced localized drug delivery in tumor chemotherapy. Here, well-defined PEGylated dendritic polyurethane (Ph-DPU-PEG) was synthesized as unimolecular micelles with a hydrophobic core via a facile one-pot method for ultrasound-triggered localized drug delivery. The chemotherapeutic drug could be encapsulated in the hydrophobic cores, and the drug-loaded micelles (DOX@Ph-DPU-PEG) were obtained as nanomedicine, which would hardly release the drug without ultrasound, regardless of the acidity of the releasing media. However, they showed an excellent ultrasound-triggered intracellular drug release performance, with a cumulative drug release of 81.6% in the simulated tumor intracellular microenvironment within 12 h. Furthermore, the ultrasound-triggered intracellular drug release was revealed with the CLSM technique and an enhanced tumor growth inhibition was achieved on the HepG2 cells compared to free DOX.