It is well established that micro- and nanoplastics (MNPs) are present in the environment, but knowledge gaps remain regarding their abundance in humans. Therefore, reliable methods to characterize MNP presence, morphology and chemistry in complex media such as human tissues are needed.
On July 11, 2025 Laura M. Zoutendijk from Utrecht University, the Netherlands, together with other AURORA scientists published a new study in the peer-reviewed journal Environmental Toxicology and Chemistry responding to that need. The researchers report the development and validation of a pre-processing protocol for the analysis of micro- and nanoplastics (MNPs) in human placental tissue.
In their workflow, the authors spiked human placental samples with fluorescent polystyrene beads of four sizes (200 nm, 500 nm, 1 µm and 10 µm) and systematically tested eight enzymatic digestion treatments, ranging from single-enzyme protocols to enzyme cocktails, across four buffer systems differing in pH and ionic strength. For each enzyme–buffer combination, tissue clarity, residual organic debris and the integrity of the particles were assessed to determine suitability for downstream analysis.
The optimal protocol achieved near-complete digestion of the placental tissue while maintaining the integrity of all tested particle sizes. Post-digestion samples were compatible with fluorescence microscopy for rapid localization of MNPs, scanning electron microscopy (SEM) for high-resolution imaging, and micro-spectroscopy for chemical fingerprinting. Recovery rates were quantified for each size class, demonstrating that the protocol minimizes particle loss during processing.
By providing a standardized sample-preparation method tailored to human placental tissue, this work could enable inter-laboratory comparability in exposomic and toxicokinetic studies of MNPs. Researchers could apply the protocol to investigations of maternal-fetal transfer, accumulation patterns, and potential health impacts of MNPs during pregnancy.
Reference
Zoutendijk, L. M., et al. (2025). “Development of a reliable preprocessing protocol for fluorescent micro- and nanoplastic analysis in human placental tissue.” Environmental Toxicology and Chemistry. DOI: 10.1093/etojnl/vgaf177
