Open Access

The topic of micro- and nanoplastics received significant attention in recent decades due to increasing environmental exposure, strong public perception, and emerging health concerns. While knowledge regarding detection and material characteristics has improved, the understanding of impact on cells remained unclear. As biological effects are initially caused by molecular interactions, consequently direct interactions with biomolecules, such as enzymes, are of particular relevance. In this occasion, effects may vary depending on the plastic type and particle properties. The specific aim of this study was to characterize the direct molecular interactions by means of selected model proteins and a variety of different nanoplastic particles. Therefore, the aim of the study was to exemplarily characterize α-amylase’s (as a model enzyme) interactions with different nanoplastics and the resulting effects on enzyme structure and function, as well as cellular responses. The properties of the α-amylase–nanoplastic mixtures were analyzed using dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), fluorescence spectroscopy, and Phadebas amylase activity test. Additionally, Caco-2 cells were used as a model system for the human intestinal barrier and exposed to these complexes to evaluate cellular uptake through flow cytometry, microscopy, and viability testing. All applied nanoplastics interacted with α-amylase, forming complexes with adsorption affinities that depended on the particle type (PP ≫ PE > PET ≫ PLA). FTIR and fluorescence analyses showed particle-specific structural changes. Despite these differences in structural response, concentration-dependent enzyme inhibition was measurable, depending on the particle type. Uptake studies on Caco-2 cells indicated no internalization or cytotoxicity. These findings suggest that nanoplastics influence the enzyme structure and function based on their chemical properties, offering new insights into direct enzyme–nanoplastics interactions and their potential impacts on enzymes and cells.

Growing production and use of plastics have led to significant environmental pollution including the formation and accumulation of plastic nanoparticles (PNPs). Due to their small size, PNPs easily enter the human food chain; however, humans are also exposed to plastics through other consumer pathways, such as the use of cosmetic products. Despite considerable efforts to investigate the potential adverse effects of plastics, their impact on human health is not yet fully understood. In particular, endocrine disruption has emerged as a potential mechanism underlying reported reproductive and hormonal effects of micro- and nanoplastics. We applied an OECD-aligned in vitro test guidelines (TGs) to a factorial panel of eight PNPs spanning four common polymers (polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET)) with size-resolved materials and polymer-matched mixtures. Thus, estrogen receptor a (ERα) transactivation (TG 455), androgen receptor (AR) transactivation (TG 458, antagonist mode), and H295R steroidogenesis (TG 456) assays were performed using HeLa-9903, AR-EcoScreen GR KO M1, and NCI-H295R cell models, respectively. Across 0.1–10 mg L⁻¹, no cytotoxicity was observed. PENPs (350 nm) and PPNPs (180 nm) acted as ER agonists, whereas PPNPs (50 and 180 nm) and PENPs (350 nm) antagonized AR; PSNPs and PETNPs showed no activity when tested individually. Notably, several mixtures elicited ER and AR responses even when constituent singles were inactive, indicating mixture-dependent potentiation. In contrast, the H295R assay did not meet the OECD decision rule for altered steroidogenesis: sporadic shifts in pathway intermediates did not propagate to estradiol or testosterone. Altogether, the data support a surface- and polymer-dependent, receptor-proximal mode of action for PNPs and highlight mixture effects as a critical, underappreciated driver. These results move endocrine hazard evaluation beyond polystyrene surrogates and provide decision-useful guidance on which polymers/sizes and mixture contexts merit priority in exposure monitoring and risk assessment.

Microplastic (MP) analysis relies on complex, multi step analytical workflows in which methodological choices made at early stages directly affect quantitative resu lts. Evidence from the literature indicates that the predominant source of variability stems from insufficient method validation and harmonisation of analytical procedures. MP measurements arise from a sequence of interdependent steps, including sampling, sample pre treatment, extraction and filtration, polymer identification, quantification and data processing. Variations in these steps — such as digestion efficiency, filter retention behaviour, contamination control and spectral parameter selection — systematically lead to non comparable datasets across laboratories and analytical techniques. Without explicit control of these factors, MP data frequently lack cross study consistency, limiting their interpretation in exposure assessment studies and their applicability in regulatory contexts requiring harmonised, validated and traceable measurements. Evidence from interlaboratory and cross technique studies, including comparisons between different IR based systems and Raman spectroscopy, demonstrates that differences in sample preparation, filtration and analytical parameter selection can outweigh instrumental performance in determining MP results. This work presents a workflow oriented framework for MP analysis that identifies critical control points and defines the methodological elements required to control them. For each key analytical step, the role of Standard Operating Procedures (SOPs) in defining operational boundaries is addressed, together with the use of fit for purpose reference materials (RMs) that mimic to assess recovery and performance across the analytical workflow. The implementation of systematic quality assurance and quality control (QA/QC) measures, the establishment of reporting limits (RLs), and the role of interlaboratory comparison studies (ILC) are discussed as essential components for ensuring reproducible, traceable and standardisation MP measurements, providing a practical basis for improving cross‑laboratory and cross‑technique comparability in regulatory‑relevant applications.

This talk shows first results of the VAMAS interlaboratory comparison for nanoplastic polyproplene particles in water suspension. The aim was to determine the variability of different instrumental techniques in the field of nanoplastic analytics. The particles had a mean diameter of around 180 nm and were broad size distributed. Various techniques were applied, e.g. mass-based techniques (Py-GC/MS and TED-GC/MS) and scattering techniques (DSL, MADSL) as well es PTA and FFF-MADSL. Data treatment was done according to ISO 5725-2. Up to 16 labs participated per technique.

While the temptation to apply for synchrotron beamtime for your experiment may be high, there are significant downsides to doing experiments there. Limited measurement time, beam damage due to high flux, and long delays between application, decision and actual experiments being just a few of these. A friendly neighbourhood laboratory instrument may provide data that is as good or even better than what the synchrotron will provide, and can even provide more comprehensive experimental support. This presentation discusses the advantages and disadvantages of either facility, and provides a range of common and uncommon examples of experiments that may be done at a laboratory facility.