LAUSR

Abstract Purpose: The aim of the present study was the in vivo assessment of the effects of gold nanorod (AuNR)-mediated laser ablation (LA) of flank xenograft tumours. We investigated: the differences between intra-tumoural (TIT) and surface tumoural temperature (TS); the influence of AuNRs concentration and laser power (P) on both these temperatures and on tumour regression. Lastly, experimental data were used to validate a theoretical model developed to predict the effects of AuNR-mediated LA. Materials and methods: Thirty-two nude mice were treated using near-infra-red light at two P, 3 d after injecting increasing AuNR doses. TIT and TS were recorded during the procedure by two thermocouples, one located within the tumour and the other one on the skin adjacent to the tumour. Tumour regression was assessed 2 d after near-infra-red exposure via Xenogen imaging. A three-dimensional temperature map was obtained by finite element modelling. Results: TIT and TS difference is substantial when AuNRs are injected. Moreover, the maximum temperature reached is strongly influenced by both P and AuNR concentration. Tumours heated above 55 °C experienced regression. Good agreement between experimental and theoretical TIT was found (maximum difference of 4 °C). Conclusions: Data show significant influence of P and AuNR concentration on the temperatures reached during AuNR-mediated LA of solid tumours. TS and TIT difference increases with AuNRs concentration. Simulated temperatures agree quite well with experimental data. Together, these results represent the first step towards a rationally designed strategy to select the most promising laser settings and AuNRs concentration to improve solid tumour treatment outcomes.