Generation of Simulated "Natural" Nanoplastics from Polypropylene Food Packaging as the Experimental Standard.

Current toxicology research on nanoplastics (NPs) generally uses commercial spherical NPs. However, the physicochemical characteristics of commercial NPs are significantly different from those of NPs formed under natural conditions, possibly affecting the validity of the results. In analytical chemistry, a reference sample is selected such that its physicochemical properties are as similar as possible to the target. Therefore, a simulated "natural" NP synthesized in the laboratory that closely resembles naturally derived NPs would be used as an authentic standard. Here, we established the assay of scanning electron microscope (SEM)-particle size distribution analyzer (PSDA)-surface-enhanced Raman scattering (SERS) to detect NPs and prepared simulated "natural" NPs from polypropylene food packaging material using a method that mimics natural conditions. Nanofiltration was used to isolate three sets of simulated NPs with particle sizes ranging from 50-100 nm, 100-200 nm, and 200-400 nm. These simulated "natural" NPs were more similar to naturally occurring counterparts when compared with commercial NPs. These new standard NPs, which should be scalable for large-scale use, will improve the accuracy, reliability, and translatability of toxicological studies of NPs.