Investigation of the heating properties of platinum nanoparticles under a radiofrequency current

Purpose: For the potential application of platinum nanoparticles (PtNPs) in hyperthermia therapy, the heating efficiency of PtNPs in the presence of radiofrequency (RF) current generated by a capacitive electric transfer (CET) system was compared with that of gold nanoparticles (AuNPs). Materials and methods: PtNPs and AuNPs synthesised by citrate capping (5 nm) were exposed to an RF current of 0.35 +/- 0.05 MHz in a CET system. The temperature of the solution containing various concentrations of platinum or gold NPs was monitored for 5 min at various power ranges. Results: When both NP solutions were exposed to an RF field at a fixed power, the temperature of the NP solution increased continuously over the 5 min of measurement. In contrast, the NP-free solutions did not show any temperature change. Both PtNPs and AuNPs can be heated in a concentration-and power-dependent manner. However, PtNPs showed a higher efficiency in generating heat compared with AuNPs in both water and the physiological buffer. Conclusions: The heat generating efficiency of 5-nm PtNPs was about 50% higher than that of AuNPs when they were exposed to electric current through RF. This result suggests that PtNPs are promising nanomaterials for RF-induced hyperthermia therapy.