Enhanced photothermal therapy using gold nanodroplets

Photothermal therapy is potentially an effective approach to treat cancer. By targeting gold nanorods (AuNRs) to specific tumor sites, laser irradiation can heat the AuNRs and elevate temperature to kill tumor cells. Concentration of AuNRs that can be delivered to tumor cells is the key factor for treatment effects. To enhance delivery, AuNRs encapsulated in perfluorocarbone nanodroplet (AuND) is of particular interest. We hypothesize that by utilizing ultrasound and laser at the same time, AuNDs will undergo liquid-to-gas phase change and the associated cavitational effects will significantly enhance AuNR delivery. To test this hypothesis, in vitro experiments were performed. Results show that the destruction ratio of AuNDs is 45% when both ultrasound and laser are applied. With gold microbubbles (AuMBs) where no liquid-to-gas phase change is present, the destruction ratio is only 35%. Furthermore, the AuNR concentration in the cells is 1.5 times higher for AuNDs than AuMBs. Thus, the combination of laser and ultrasound and the use of AuNDs have the potential to significantly enhance targeted photothermal therapy effects.