Thermosensitive liposome-encapsulated gold nanocage for photothermal-modulated drug release and synergistic photothermal therapy

Delivery nanosystems were popularly developed to improve chemotherapy efficacy, but the non-specific leakage of drugs was still not satisfactory. Here, using gold nanocages (AuNCs) as carrier and thermo-sensitive liposome (TSL) as protection shell, a camptothecin (CPT) loaded delivery nanosystem (AuNCs/CPT@TSL) was designed for photothermal-modulated drug release, by which the non-specific leakage of CPT was avoided, and the combination of photothermal therapy (PTT) and chemotherapy was achieved. In the simulated tumor microenvironment (pH=5.5), the TSL shell protected CPT from leakage at 37℃, and the release rate of CPT was only 11.4%. However, the release rate of CPT greatly increased to 85.4% by elevating temperature to 45℃. The photothermal conversion efficiency of AuNCs/CPT@TSL reached up to 46.1%. When the incubation temperature was 37℃, the cell survival rate was reduced to 43.6% in AuNCs/CPT, but was still above 90% in AuNCs/CPT@TSL, demonstrating the good protection of TSL shell. Under the combination of PTT/chemotherapy, the cell viability greatly decreased to 10.9%, and the tumors completely disappeared, confirming the safe and reliable antitumor effect of AuNCs/CPT@TSL.