Bioactivity of mycosynthesized nanoparticles assists photothermal therapy of breast cancer cells

Chaga mushroom (Inonotus obliquus) exhibits cytotoxic effects against breast cancer cells. Mycosynthesized nanoparticles, owing to their biodegradability, biocompatibility, and low toxicity, present a promising therapeutic approach. This study explored the cytotoxic potential of gold nanoparticles synthesized using Chaga mushroom extract (AuCh-NPs) combined with Light Emitting Diode (LED) irradiation (530 nm) on human breast cancer (MCF-7) cells, aiming to develop a safe and effective sensitizer for photothermal therapy. The AuCh-NPs were characterized using UV-visible spectroscopy, FTIR, TEM, particle size analysis, and zeta potential measurements. Cytotoxicity was evaluated via MTT assay under LED irradiation with total light exposure 325.8 and 488.7 J cm^-2, alongside mechanistic studies involving wound healing, autophagy, cell cycle arrest, annexin V analysis, real-time PCR, and comet assays.TEM revealed spherical AuCh-NPs with sizes ranging from 15.4 to 28.9 nm. The MTT assay demonstrated enhanced cytotoxicity under LED irradiation, with AuCh-NPs exhibiting a lower IC50 (5.56 µM) than citrate-capped gold nanoparticles (AuCit-NPs, 7 µM). Cell cycle analysis revealed significant arrest in G0/G1 (91.68%) and S (7.55%) phases, while annexin V analysis confirmed apoptosis induction. Real-time PCR showed upregulation of the pro-apoptotic genes BAX, and the comet assay indicated increased double-strand DNA damage in MCF-7 cells treated with AuCh-NPs compared to AuCit-NPs. These findings highlight the superior selective cytotoxicity of AuCh-NPs against MCF7 cells, positioning them as a promising targeted agent for photothermal therapy in breast cancer treatment.