Characterization of the Laser-induced Thermal Outcome of Gold Nanorods-mediated Photothermal Therapy in Breast Cancer Cells

In this study, we devised the characterization of the thermal outcome of gold nanorods (AuNRs)-mediated photothermal therapy (PTT) in triple-negative murine 4T1 cell line, employed as a model of breast cancer. After examining the characteristics of AuNRs and their internalization into 4T1 cells, we monitored in real-time the thermal effects on cells upon in vitro AuNRs-mediated PTT exploiting high-performant thermographic imaging. Multiple parameters, such as the temperature evolution, maximum temperature attained during laser exposures, normalized temperature, effective thermal enhancement (TE) and heating efficiency (HE) were derived through the analysis of the thermographic images. The cell viability values following exposure were used to evaluate the cells' biological response and compared with the results of the thermal analysis. The thermal parameters were found to correlate with the extent of cell death. With the highest concentration of AuNRs tested, a combination of AuNRs pretreatment and laser irradiation resulted in a decrease of 94% in cell viability compared to the control group, coinciding with a maximum temperature of 55 °C, TE = 37%, and HE = 1.8. The results of this work set the basis for the investigation of the thermal outcome of photothermal procedures on breast cancer cells toward the fine-tuning and responsible translation of PTT in vivo scenarios.Clinical Relevance - This work highlights it is pivotal to characterize the thermal effect induced in cancer cells and correlate it with the cell biological response to increase the therapeutic efficacy of nanoparticle-assisted PTT for a transition toward the clinical setting