Nanotoxicological evaluation of biosynthesized molybdenum trioxide nanoparticles supported on rice husk silica: In vitro safety profile, ecotoxicity, and phytotoxicity.

This study evaluated the nanotoxicity of SiO2/MoO3-NPs nanocomposite, where the matrix (SiO2) was obtained from rice husk residue, and the nanoreinforcement (MoO3-NPs) was biosynthesized using Araucaria angustifolia extract. The in vitro safety profile was evaluated in VERO cells, and toxicity in soil and phytotoxicity in cabbage seeds (Brassica oleracea) were investigated. Cell viability and proliferation (MTT), oxidative stress (ROS generation), nitric oxide (NO generation), and DNA damage (dsDNA) data revealed that SiO2 was biocompatible, whereas MoO3-NPs elicited more pronounced biological responses, with anti-inflammatory effects up to 85% (100 µg mL-1 for 48 h). In terms of phytotoxicity, MoO3-NPs demonstrated a hormetic effect on photosynthetic pigments, stimulating them at 25 µg mL-1 and inhibiting root growth at high doses (50 and 100 µg mL-1). The SiO2/MoO3-NPs nanocomposite behaved in an intermediate manner, suggesting that the silica matrix had a modulating effect, decreasing the nanotoxicity of MoO3-NPs. Therefore, nanomaterial hybridization is a promising approach to minimize environmental and biological risks, enabling the safe development of sustainable nanotechnologies. Thus, nanomaterial hybridization proves to be an effective approach to minimize risks to the environment and health, ensuring safe progress in the development of sustainable nanotechnologies.