A Bacterial Enzymatic System Neutralizes the Impact of Silica-Magnetite Nanocomposites on ROS Levels

Abstract

This study investigates the reactive oxygen species (ROS) generation and biological activity of novel silicamagnetite nanocomposites, TA-AA-Fe3O4 and TA-HA-Fe3O4, where TA is a silicon dioxide copolymer, AA is ascorbic acid, and HA is humic acids. A key challenge in nanotoxicology is the contradictory data from complex biological systems. To address this, we employed a standardized bioluminescent enzymatic assay (bacterial luciferase/oxidoreductase) as a simple, rapid biosensor system to evaluate the nanocomposites’ effects under controlled conditions. We compared ROS activity in both non-biological (enzyme-free aqueous solutions) and biological (enzymatic system) environments, with and without model oxidative stress induced by 1,4-benzoquinone. The enzymatic system exerted a pronounced neutralizing effect on ROS content, suppressing the significant ROS fluctuations and synergistic ROS generation (up to 300%) observed in nonbiological media in the presence of the oxidizer. Additionally, the nanocomposites showed no effect on the bioluminescence intensity of the enzymatic system. This disparity between the higher reactivity in simple aqueous solutions and the neutral effect in the enzymatic system highlights the critical role of biological matrixes. The findings suggest that enzymatic environments can mitigate the radical processes driven by ironbased nanocomposites, which is crucial for predicting their biological activity and potential for applications like ferroptosis-based tumor therapy.