Quantifying nanoplastic cellular interactions and uptake pathways by label-free plasmonic imaging

Nanoplastics are increasingly detected in environmental and biological systems, yet quantitative understanding of their cellular interactions and uptake pathways remains limited, particularly under label-free conditions. Here, we employ surface plasmon resonance microscopy (SPRM) to investigate nanoplastic-cell interactions in real time with single-cell resolution. Using 200 nm polystyrene nanoparticles and HEK293 cells as a model system, we quantify the relative contributions of nanoplastic association with cells, including surface adsorption (8.47%), passive uptake (5.95%), and active internalization (85.58%), the latter further comprising clathrin-mediated (44.35%), caveolae-mediated (46.26%), and macropinocytosis-mediated pathways (9.39%). This study establishes SPRM as a label-free platform for quantitatively analyzing nanoplastic-cell interactions and provides a foundation for extending such analyses to more complex and environmentally relevant nanoparticle systems. SYNOPSIS: A label-free surface plasmon resonance microscopy approach quantitatively dissects nanoplastic-cell interaction pathways at the single-cell level.