“By employing optical photothermal infrared (OPTIR) spectroscopy, we achieved submicron spatial resolution, enabling precise localization and chemical identification of PE, PS and PET particles, surpassing the spatial limitations of conventional infrared microscopy.”
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Reporting in Scientific Reports, researchers at Medical University Vienna and the Research Center for Non-Destructive Testing established a clinically compatible method for detecting microplastic particles in routinely processed human tissue samples. Microplastic pollution represents a critical environmental and public health concern, with emerging evidence indicating accumulation in human organs. However, detecting these particles in formalin-fixed paraffin-embedded (FFPE) tissue—the standard format for clinical pathology—has been challenging due to particle size, chemical composition, and the loss of spatial information inherent to conventional tissue digestion methods.
The team employed optical photothermal infrared (OPTIR) spectroscopy to analyze deparaffinized FFPE human colon tissue sections from three patients. Using an optimized workflow, researchers identified regions of interest based on tissue architecture, then performed chemical analysis at characteristic wavenumbers targeting specific polymer types. The method detected 21 predominantly spherical polyethylene particles (3–6 μm) across two tissue regions in one sample, plus single polystyrene and polyethylene terephthalate particles in two additional samples. Full spectral analysis validated particle identity through comparison with reference spectra. Following OPTIR analysis, identical sections underwent hematoxylin and eosin staining, revealing inflammatory features including lymphocytic infiltration and neural hyperplasia in proximity to the identified microplastic particles.
OPTIR spectroscopy achieved lateral resolution of approximately 500 nm, representing a 30-fold improvement over conventional FTIR microscopes and enabling detection of submicron structures within complex tissues. The non-destructive technique preserves tissue architecture, permitting subsequent histopathological analyses without requiring specialized substrates or altered sample preparation. The method maintains compatibility with standard clinical workflows and enables retrospective analysis of archived pathology specimens, offering a scalable approach for investigating microplastic burden across patient cohorts.
This represents the first demonstration of a diagnostic workflow enabling combined infrared spectroscopic and histopathological analysis of microplastics in routinely processed human FFPE tissue. The integration of high-resolution chemical characterization with preserved spatial information provides a promising avenue to elucidate the role of microplastic accumulation in human disease and supports investigation into potential mechanistic links between microplastic exposure and inflammatory processes.
Authors:
Elisabeth S. Gruber, Verena Karl, Kristina Duswald, Mukund S. Bhamidipalli, Michaela Schlederer, Tanja Limberger, Verena Kopatz, Béla Teleky, Lukas Kenner & Markus Brandstetter
