Evolution of Physicochemical and Toxicological Properties During Aqueous Exposition of the Nanoparticulated Food Colours E-174 and E-172: Study in Caenorhabditis elegans

Abstract

This study explores the toxicological effects of silver nanoparticles (AgNPs) and iron oxide nanoparticles (Fe₂O₃NPs), used as food colours (E-174 and E-172, respectively), upon contact with aqueous medium that simulates food matrices. Despite being authorized, the safety of these additives remains uncertain. Their effects on physicochemical and biological parameters were evaluated using the in vivo model Caenorhabditis elegans, assessing lethality, oxidative stress, cell death and movement behaviour. Physicochemical analysis showed significant property changes in the NPs upon contact with the aqueous medium. AgNPs exhibited greater stability, with zeta potential values of − 27.71 ± 0.47 mV, compared to Fe₂O₃NPs (− 10.09 ± 0.46 mV) (both at 50 µg/mL). Fe₂O₃NPs revealed increased solubilization, leading to higher toxicity, reflected in elevated lethality rates (43.54 ± 0.329% for Fe₂O₃NPs, compared to 20.00 ± 0.287% for AgNPs) and oxidative stress values (0.99 ± 0.007 for Fe₂O₃NPs and 0.98 ± 0.010 for AgNPs). Additional analysis of cell apoptosis and movement behaviour further highlighted these toxic effects, showing cell death values of 1.06 ± 0.008 for AgNPs and 1.003 ± 0.008 for Fe₂O₃NPs (all at 50 µg/mL). The results emphasized the critical role of NP physicochemical properties and their biological interactions, demonstrating that stability variations can enhance their toxic potential, when used as food additives. Findings call for comprehensive research to better understand NP behaviour in food matrices and associated health risks, ensuring consumer safety.