Factors affecting the 13.56-MHz radio-frequency-mediated heating of gold nanoparticles

ABSTRACTThe use of radio-frequency (RF) energy for the thermal activation of tumor-targeted nanoparticles (NPs) is a promising non-invasive hyperthermic treatment because RF waves penetrate deep through tissue. Nonetheless, while the approach has been demonstrated using gold (Au) and iron oxide NPs, the RF-mediated heating mechanism of AuNPs has been controversial. A part of the reason is that measuring and modeling the heating of AuNPs in an RF field is a complex endeavor that depends on the chemical and physical properties of the AuNPs, interfacial phenomena involving AuNP coatings and the sample medium, and the antenna design and characteristics of the RF field. Herein, the mechanisms and factors affecting the 13.56-MHz RF-mediated heating of AuNPs are reviewed, a new factor concerning the thermal isolation of RF antennae is presented, and the ability of a new water-free cooling system to thermally isolate samples from the heat generated by metal RF-induction coils is demonstrated.