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

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 via 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 in vivo 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 (p < 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.