Revealing Trace Nanoplastics in Food Packages─An Electrochemical Approach Facilitated by Synergistic Attraction of Electrostatics and Hydrophobicity.

Most food packages are made of plastics, nanoplastics released from which can be directly ingested and induce serious damage to organisms. Therefore, it is urgent to develop an effective and convenient method for nanoplastic determinations in food packages. In this work, we present a sandwich-based electrochemical strategy for nanoplastic determination. Positively charged Au nanoparticles were coated onto a Au electrode to selectively capture negatively charged nanoplastics in an aqueous environment. Subsequently, the nanoplastics were recognized by the signal molecule ferrocene via the hydrophobic interaction and determined by differential pulse voltammetry. Our sandwich-type detection depends on both electronegativity and hydrophobicity of nanoplastics, which make the method applicable for the assays of packages made of widely commercialized polystyrene (PS), polypropylene (PP), polyethylene (PE), and polyamide (PA). The method displays different sensitivities to above four nanoplastics but the same dynamic range from 1 to 100 µg·L-1. Based on it, the nanoplastics released from several typical food packages were assayed. Teabags were revealed with significant nanoplastic release, while instant noodle boxes, paper cups, and take-out boxes release slightly. The good recoveries in nanoplastic-spiked samples confirm the accuracy and applicability of this method. This work provides a sensitive, low-cost, and simple method without complicated instruments and pretreatment, which is of great significance for the determination of nanoplastics released from food packages.

Impact of nanoplastics on Alzheimer 's disease: Enhanced amyloid-ß peptide aggregation and augmented neurotoxicity.

Nanoplastics, widely existing in the environment and organisms, have been proven to cross the blood-brain barrier, increasing the incidence of neurodegenerative diseases like Alzheimer's disease (AD). However, current studies mainly focus on the neurotoxicity of nanoplastics themselves, neglecting their synergistic effects with other biomolecules and the resulting neurotoxicity. Amyloid ß peptide (Aß), which triggers neurotoxicity through its self-aggregation, is the paramount pathogenic protein in AD. Here, employing polystyrene nanoparticles (PS) as a model for nanoplastics, we reveal that 100 pM PS nanoparticles significantly accelerate the nucleation rate of two Aß subtypes (Aß40 and Aß42) at low concentrations, promoting the formation of more Aß oligomers and leading to evident neurotoxicity. The hydrophobic surface of PS facilitates the interaction of hydrophobic fragments between Aß monomers, responsible for the augmented neurotoxicity. This work provides consequential insights into the modulatory impact of low-dose PS on Aß aggregation and the ensuing neurotoxicity, presenting a valuable foundation for future research on the intricate interplay between environmental toxins and brain diseases.