Non-photoaging and eco-corona reinforce nanoplastics-root engagement via root exudates in the rhizosphere.

How non-photoaging alters the binding of rhizosphere nanoplastics to root exudates (eco-corona) and subsequent root surface interactions remains unclear. Here, polystyrene nanoplastics (PSNPs) were subjected to Fenton and sulfidation aging. Spectroscopic analyses showed that root exudates formed distinct eco-coronas on pristine and aged PSNPs via non-covalent interactions. Aging shifted the binding mode from weak hydrophobic adsorption on pristine PS to hydrogen-bonding interactions with organic acids on aged PS. Consequently, colloidal behaviors differed, with hydrodynamic sizes increasing to 400 nm (pristine), > 600 nm (Fenton-aged), or fluctuating markedly (sulfide-aged). Confocal imaging showed that aging reduced PSNP adsorption on root protoplasts, whereas eco-corona formation decreased adsorption of pristine PS but markedly enhanced that of aged PS. Mechanistically, the corona masked hydrophobic sites on pristine PS, while carboxyl groups with residual Fe²⁺/Fe³⁺ promoted electrostatic/cation bridging on Fenton-aged PS, and carboxyl-rich exudates together with surface radicals enhanced punctate clustering and endocytosis on sulfide-aged PS. Root exposure experiments further showed that sulfide-aged PS exhibited an "easy adsorption, easy elution" pattern, mainly accumulating in the root elongation zone with a thin mucus layer. These findings demonstrate that aging reshapes nanoplastic surface chemistry, thereby regulating eco-corona formation and reprogramming interactions with the root surface and plasma membrane.