New Imaging Method Detects Microplastics in Intact Human Tissue

Researchers at the Medical University of Vienna have demonstrated a new way to detect microplastics inside human tissue without cutting or dissolving the sample. The work introduces a non-destructive method based on Optical Photothermal Infrared Spectroscopy (OPTIR), offering researchers the first opportunity to locate and identify plastic particles directly within intact biological structures.

A group led by Lukas Kenner at MedUni Vienna, working in partnership with RECENDT GmbH – Research Center for Non-Destructive Testing, has now shown that OPTIR can provide chemical identification of microplastics while keeping tissue fully preserved.

Duswald, K., Pichler, V., Kopatz, V., Limberger, T., Karl, V., Hennerbichler, D., Zimmerleiter, R., Wadsak, W., Hettich, M., Gruber, E. S., Kenner, L., & Brandstetter, M. (2025). Detection of Unlabeled Polystyrene Micro- and Nanoplastics in Mammalian Tissue by Optical Photothermal Infrared Spectroscopy. Analytical Chemistry, 97(31), 16714–16722. https://doi.org/10.1021/acs.analchem.4c05400

Microplastic exposure has become a central concern in environmental and biomedical research. Yet, scientists have struggled to examine where these particles reside in the body because most analytical tools require destroying tissue to detect plastics. This limitation has made it difficult to link microplastic presence to inflammation, chronic conditions, or other physiological changes.

Lukas Kenner from MedUni Vienna stated,

“In the recently published study, we were able to identify various microplastic particles in human colon tissue, including PE, PS and PET. These were found to be conspicuously frequent in areas with inflammatory changes.”

OPTIR is an emerging technique originally developed for materials science. It uses an infrared laser to heat microscopic regions of a sample. Plastics such as polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET) absorb infrared light in characteristic ways determined by their chemical structure.

A second light source measures the subtle thermal response, creating what researchers describe as an “infrared fingerprint.” This fingerprint reveals the type of polymer present without altering the surrounding biological matrix.

Unlike Raman microscopy and other spectroscopic tools, OPTIR does not rely on fluorescent labels or staining. It provides high spatial resolution and can analyze embedded particles smaller than one micrometer

One of the key achievements of the Vienna team is demonstrating that OPTIR works on FFPE (formalin-fixed, paraffin-embedded) tissue—the standard format used in pathology labs worldwide. FFPE samples are routinely archived and contain preserved tissue architecture, making them ideal for medical studies.

Using OPTIR, the researchers identified PE, PS, and PET particles in intact human colon tissue. Importantly, these particles appeared more frequently in regions showing inflammatory changes. Because the tissue remains unharmed, the optical data can be paired with histology or genetic analysis from the same sample, giving researchers a way to study potential biological interactions surrounding the microplastics.

This approach provides a path to understanding whether microplastics accumulate in damaged or stressed areas of tissue, and how their presence relates to inflammation or disease progression.

To assess detection limits, the team carried out additional experiments using mouse tissue and three-dimensional cell cultures. These controlled settings allowed them to confirm that the method can detect particles as small as 250 nanometers—about a quarter of a micrometer.

The plastics evaluated—PE, PS, and PET—represent some of the most common consumer materials, found in items including cling film, disposable bottles, food packaging, and plastic bags. Establishing reliable detection methods for such materials is essential for building a clearer picture of human exposure.

The ability to visualize microplastics directly inside intact tissue is a significant step for environmental health research. Many questions remain about how plastics move through the body, whether they accumulate in specific organs, and how they may contribute to long-term conditions.

By pairing non-destructive imaging with traditional clinical assessment, researchers can now begin to link microplastic presence to the biological environment in which it appears. This includes examining nearby inflammation, immune activity, or changes in tissue structure.

The work provides a foundation for future studies examining microplastic exposure in larger patient cohorts, evaluating correlations with chronic conditions, and developing standardized imaging protocols for clinical laboratories.