Key Parameters in Phototherapy with Gold Nanorods Using Continuous Near Infrared Radiation

Abstract

Abstract As nanoparticle formulations move toward human clinical trials in photothermal cancer therapy (PTT), the influence of individual key parameters on the heating efficacy must be thoroughly assessed. This work reports a systematic study on the heating performance of gold nanorods during exposure to near‐infrared radiation, evaluating the influence of nanorods concentration, total volume, laser output power, and spot area. Interestingly, the lowest concentration tested (24 µg mL−1) shows the most promising results with a SAR (Specific Absorption Rate) value of 24.6 kW gAu−1 for the highest laser power (0.8 W), spot area (0.4 cm2), volume (1 mL). The laser output power and concentration proved to be the key parameters in global heating of the sample. The cuvette's optical path length also proves to be an important parameter given that there is a threshold concentration value beyond which no significant improvement will be observed, and the higher gold mass will play a detrimental role suppressing SAR values. It is experimentally demonstrated that the multi‐parameter exploration can lead to a finer control of the performance in PTT, opening a pathway for efficient heating of low nanoparticle concentrations.

Keywords

• continuous laser
• gold nanorods
• oncology
• phototherapy