Smaller Plastics, Bigger Risks: The Invisible Threat of Nanoplastics and Microplastics in Biological and Environmental Samples Analyzed with Multimodal Submicron IR (O-PTIR) and Simultaneous Raman

Microplastic (MP) and nanoplastic (NP) contamination has become a global concern, with particles now routinely detected in air, water, soil, and food. Human and animal exposure occurs via ingestion and inhalation, and growing evidence suggests that smaller MPs and NPs can cross biological barriers, accumulate in tissues, and impact health. To assess these risks, researchers need reliable tools to detect and chemically characterize particles well below 10 µm, even submicron (NP)—the most biologically and environmentally relevant fractions.
Conventional spectroscopic approaches such as FTIR, QCL, and Raman are limited in this regime due to poor spatial resolution, scattering artefacts, fluorescence interference, or low sensitivity. As a result, MPs and NPs below ~10–20 µm have remained largely invisible to current analysis methods.
Optical Photothermal Infrared Spectroscopy (O-PTIR) overcomes these limitations by coupling infrared absorption with a visible probe beam, achieving spatial resolution 10–30× smaller than traditional IR diffraction limits. This enables label-free, non-destructive analysis of MPs and NPs down to 200 nm, free from the spectral artefacts and fluorescence issues that compromise other techniques. Importantly, O-PTIR can be automated and integrated with Raman spectroscopy, allowing high-throughput analysis of particles extracted and filtered from environmental matrices as well as those embedded in tissues or 3D cell models.
Case studies will be presented demonstrating robust chemical identification and mapping of MPs/NPs in real-world samples—including environmental extracts and biological tissues. By enabling reliable detection of polymeric particles from 200 nm upward, O-PTIR finally provides access to the size fractions that matter most for understanding exposure pathways, environmental distribution, and potential health effects.