Non-invasive imaging-guided preclinical assessments reveal high performance photothermal effect of an Au-solid lipid nanomaterial

With the rising global cancer crisis, photothermal therapy (PTT) has emerged as a promising treatment for solid tumours. PTT utilizes near-infrared (NIR) photons to generate localized heat through plasmonic nanoparticles. We optimized the production of a novel PTT nanomaterial, a gold-coated solid lipid nanoparticle (Au-SLN), and characterized its functionalities using non-invasive multimodality imaging. Synthesized <i>via</i> solvent-emulsion evaporation, Au-SLNs achieved 80% photothermal conversion efficiency, surpassing that of many existing agents. The lyophilized product demonstrated high reproducibility, biocompatibility, cell permeability, and non-toxicity, which are essential for clinical translation. To evaluate <i>in vivo</i> hyperthermic potential, infrared thermography (IRT), bioluminescence imaging (BLI), NIR fluorescence (NIRF), and microCT imaging were employed using an orthotopic murine breast cancer model. IRT confirmed significant thermal elevation (<i>p</i> < 0.0001), while tomographic imaging modalities provided comprehensive insights into the primary debulking efficiency and post-treatment healing process. PTT using Au-SLNs resulted in complete remission of small tumours, but for late-stage tumours, booster dose optimization was required to deliver enhanced survival benefits. These findings underscore the therapeutic potential of Au-SLNs as an effective standalone photothermal agent for treating solid tumours. This study shows that PTT-mediated tumour debulking greatly improves post-treatment life expectancy with no visible distress symptoms, thus paving the way for its future clinical application.