Impact of AgBiS2/CuO Nanocomposite on Barley (Hordeum vulgare L.): Phytotoxicity, Genotoxicity, and Photosynthesis via Interfacial Charge Transfer.

Engineered nanomaterials are increasingly used in agriculture. Accordingly, understanding their interactions with soil-plant systems became essential to ensure environmental safety. This study investigates the rational synthesis and characterization of a novel AgBiS2/CuO nanocomposite and evaluates its phytotoxic and genotoxic impacts on barley (Hordeum vulgare L.). Structural and surface analyses were performed using XRD, FTIR, XPS, and SEM-EDX. The interfacial charge transfer was studied by optical analyses and photoluminescence quenching. The biological effects were evaluated by measuring the photosynthetic activity (Fv/Fm, NPQ, Y(II), and ETR), genomic alterations through RAPD-PCR analysis, and in vitro cytotoxicity assays. Analyses identified a high-purity biphasic architecture with efficient interfacial charge transfer modulating reactive oxygen species (ROS) generation. Optical analyses also showed significant quenching of photoluminescence intensity in the nanocomposite compared to pristine components. The prepared nanocomposite showed good biocompatibility, although high concentrations (≥ 2000 mg L-1) caused dose-dependent growth retardation and photosynthetic activity inhibition. Importantly, no genotoxic changes in barley DNA were seen through the RAPD-PCR analysis. Additionally, the viability of cells was still over 80% at doses up to 125 μg mL-1. These results indicate that the heterojunction interface mostly stabilizes the material against DNA damage and prevents acute genomic instability. The experiments of in vitro cytotoxicity demonstrated the great biocompatibility of the prepared nanocomposite, thus validating its safety profile. The outcomes of this study establish that the interfacial engineering of metal sulfide/oxide composites may decrease environmental concerns and provide opportunities for the design of high-performance nanomaterials or nanocomposites with low toxicity to agricultural crops and soil health.