Killing of gold nanorods-loaded human cardiac fibroblasts mediated by photo-thermal activation

Cardiac fibrosis is a pathological process associated with several heart diseases, characterized by extracellular matrix deposition by cardiac fibroblasts. Photothermal therapy is a minimally invasive medical treatment that uses nanomaterials to convert external light into localized heating. On these premises, we report an innovative approach that exploits gold nanorods (AuNRs)-mediated plasmonic photothermal therapy (PPTT) for selective ablation of AuNR-loaded human cardiac fibroblasts (hCFs). Cellular uptake is confirmed by treating hCFs with AuNRs, irradiating them with an 808 nm continuous-wave (CW) laser, and performing ultrastructural electron microscopy analysis. Measurements of extinction spectra, temperature variation, and cell viability were conducted. Results show that hCFs internalize AuNRs effectively without cytotoxicity, and extinction spectra reveal a concentration-dependent redshift of the longitudinal plasmon bands. Upon laser irradiation, AuNR-loaded hCFs experience a temperature increase, leading to cell death in proportion to AuNRs concentration. In coculture systems, AuNR-loaded hCFs are ablated while the viability of surrounding nonloaded cells (fibroblasts or cardiomyocytes) remains unaffected, demonstrating that hCFs can internalize AuNRs and be effectively ablated through PPTT. Our results highlight the potential of AuNRs for targeted cardiac cell ablation with minimal impact on adjacent cells.