Silver-doped MoOx NPs with phytochemicals for photodynamic therapy application: Playing with the sequence of surface modification steps

Photodynamic therapy (PDT) is a promising strategy for cancer treatment, employing photosensitizers activated by light to induce cytotoxicity. Hybrid organic-inorganic nanocomplexes, which integrate the unique properties of plasmonic metals and organic photosensitizers, are currently under intensive investigation. In this study, we propose the development of a novel photoactive nanoplatform for PDT based on a composite system comprising molybdenum oxide, silver, and phytochemicals from Hypericum perforatum and Chelidonium majus. To evaluate how the sequence of silver and phytochemicals deposition influences the optical characteristics and photodynamic performance of the resulting heterostructures, two modification strategies were employed, differing in the order of the applied synthesis steps. Primary attachment of phytomolecules led to lower silver content (8-13 wt%) and predominance of the metallic silver phase. In contrast, primary attachment of silver resulted in higher silver content (31 wt%) but predominance of the AgCl phase. Upon irradiation at 405 nm, the highest phototoxic response was observed for the sample modified first with C. majus phytochemicals and subsequently with silver. This nanocomplex exhibited a similarly strong photoresponse at both early and late irradiation stages, reducing lung cancer cell viability to ∼10 %. These findings highlight its potential for efficient and selective PDT-based cancer therapies.