Material-dependent physiological and biochemical responses of marine microalga Tisochrysis sp. to three model nanoplastics.

The physiological responses of microalgae to nanoplastics remain poorly understood, as research has focused almost exclusively on polystyrene nanospheres, limiting insight into the impacts of other polymers at the nanoscale. To address this knowledge gap, this study evaluated laboratory-generated nanoplastics (<200 nm) from polyethylene terephthalate (PET), polyvinyl chloride (PVC), and residual photopolymerisable 3D resin (PU/PA), and their effects on the physiology of Tisochrysis sp. over a 10-day exposure at 5μg/mL. Cell growth dynamics, biochemical composition, photosynthetic pigment content, cell dimensions, reactive oxygen species, superoxide dismutase and catalase activity were assessed, and principal component analysis (PCA) was used to integrate the dataset. The results revealed material-dependent physiological effects, whereas PCA revealed two distinct physiological response patterns: PET and PVC-exposed cells showed a photosynthetic pigment reorganisation that was associated with particle exposure, whereas PU/PA-Nps induced a stronger initial growth inhibition (up to 50%) that was not sustained, accompanied by a shift toward lipid accumulation reflecting a dynamic modulation of cellular redox homeostasis.