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

Abstract

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, gold-coated solid lipid nanoparticles (Au-SLN), and characterized its functionalities using non-invasive multimodality imaging. Synthesized via solvent-emulsion evaporation, Au-SLN achieved 80% photothermal conversion efficiency, surpassing many existing agents. The lyophilized product demonstrated high reproducibility, biocompatibility, cell permeability, and non-toxicity parameters 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 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-SLN resulted in a 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-SLN as an effective standalone photothermal agent for treatment of solid tumours. The study shows PTT-mediated tumour debulking greatly improves post-treatment life expectancy with no visible distress symptoms, thus paving the way for its future clinical application.