We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
How do the characteristics of polystyrene microplastics regulate their combined toxicity with nano ZnO? - Mechanism analysis based on Saccharomyces cerevisiae as a model
Summary
Microplastics don't just pollute on their own, this study found that when tiny plastic particles team up with zinc oxide nanoparticles (common in sunscreens and cosmetics), they become more toxic together than either one alone, damaging cells by causing oxidative stress and letting more zinc leak into cells. The type of surface chemistry on the plastic and its size both mattered: smaller particles and certain chemical coatings made the combo more dangerous, suggesting that as microplastics mix with other pollutants in our environment, their health risks could be worse than current safety testing, which usually looks at one pollutant at a time, might sugg
Owing to the distinct physicochemical properties and strong adsorption capacity of microplastics (MPs), they can influence the environmental fate and toxicity of both themselves and coexisting contaminants. This study systematically investigated the combined toxicity of polystyrene microplastics (PS-MPs), with different functional groups (-COOH/-NH 2 ) and particle sizes in combined with zinc oxide nanoparticles (ZnO-NPs) toward Saccharomyces cerevisiae . FTIR analysis revealed that the adsorption of ZnO-NPs on PS-MPs underwent chemisorption, hydrogen bonding and coordination complexation. Dissolution kinetics further demonstrated that both PS-COOH MPs and PS-NH₂ MPs promoted ZnO-NPs dissolution, with PS-COOH MPs exhibiting a stronger effect. The toxicological study showed that PS-MPs and ZnO-NPs exhibited a synergistic toxicity toward Saccharomyces cerevisiae . Compared to the larger-sized PS-MPs, smaller-sized PS-MPs exerted stronger toxicity via their larger specific surface area. When PS-COOH MPs coexist with ZnO-NPs, PS-COOH MPs facilitated yeast cell adsorption via Zn 2+ -mediated charge neutralization, leading to morphological deformation. In contrast, PS-NH₂ MPs enhanced membrane permeability through electrostatic and hydrogen-bonding interactions, promoting Zn 2+ influx and exacerbating cytological damage. Co-exposure significantly inhibited the activities of superoxide dismutase (SOD) and catalase (CAT), elevated malondialdehyde (MDA) levels, and induced oxidative damage in the cells. Notably, PS-COOH had a minor effect on intracellular Zn accumulation, whereas PS-NH₂ significantly enhanced it. The Zn accumulation showed a negative correlation with the particle size of PS-NH₂ MPs and a positive correlation with their dosage. This study elucidates the functional group-dependent toxicity mechanisms of PS-MPs and ZnO-NPs toward microorganisms, providing a theoretical basis for assessing the combined toxic effects of composite pollutants.