Size-dependent modulation of tetracycline hydrochloride toxicity by polystyrene micro/nanoplastics in the model freshwater ciliate Paramecium tetraurelia.

Polystyrene micro/nanoplastics (50 nm and 500 nm) significantly increase tetracycline hydrochloride toxicity in Paramecium tetraurelia, with effects varying by particle size.

• Why it matters: Understanding how micro/nanoplastics influence antibiotic toxicity is crucial for ecological risk assessments, as these pollutants often co-occur in aquatic environments, posing complex threats to aquatic microorganisms.
• What they did: The study used phenotypic, physiological, fluorescence imaging, and transcriptomic analyses to examine the effects of three sizes of polystyrene micro/nanoplastics on TCH toxicity in Paramecium tetraurelia, focusing on cellular and molecular responses.
• The result: Findings reveal size-dependent modulation, with smaller particles intensifying toxicity and larger microplastics attenuating it, emphasizing the importance of particle size in ecological risk evaluations of antibiotic-plastic co-contamination.