Chitosan-confined selenium-silver nanohybrids enable redox-modulated mitochondrial apoptosis and survival improvement...

Polymer-confined multi-metal nanostructures offer a strategy to modulate tumor redox balance with improved selectivity. Here, we engineered chitosan-stabilized selenium-silver (Se-Ag) nanohybrids as redox-regulating agents for hepatocellular carcinoma (HCC). The nanocomposite was synthesized via green routes, combining phytochemical reduction of silver nanoparticles from Allium cepa extract with ascorbic acid-reduced selenium nanoparticles, followed by confinement within a low-molecular-weight chitosan matrix. Transmission electron microscopy revealed discrete metallic nanodomains (45-205 nm) embedded in a continuous polymer scaffold, while inductively coupled plasma optical emission spectroscopy confirmed reproducible elemental loading (Se: 50.0 ± 2.5 mg L^-1; Ag: 6.0 ± 0.3 mg L^-1) and buffer stability. In a diethylnitrosamine-induced murine HCC model, treatment significantly improved survival, reduced tumor burden, and preserved hepatic architecture. Preferential hepatic accumulation (liver : kidney ratio 5.8 : 1) was observed. Mechanistically, the nanohybrids restored redox balance, reduced lipid peroxidation, enhanced glutathione and superoxide dismutase activity, and activated intrinsic mitochondrial apoptosis via the p53-BAX-caspase-9 pathway. Apoptosis was selectively localized to tumor tissue. These results establish a structure-function relationship in which chitosan-mediated confinement regulates metal release, dual-metal integration amplifies tumor-specific oxidative stress, and hepatic targeting enhances therapeutic index, supporting Se-Ag nanohybrids as a materials-driven platform for redox-based liver cancer therapy.