Rapid Identification of Microplastics in Complex Biological Matrices via High-Speed Mid-Infrared Hyperspectral Imaging

Rapid and reliable identification of microplastics in complex biological matrices remains challenging due to limited throughput or insufficient chemical specificity of existing techniques. Here, we demonstrate a high-speed and high-throughput mid-infrared hyperspectral imaging approach based on sub-cycle mid-infrared pulses. The system enables acquisition of centimeter-scale hyperspectral images covering the infrared fingerprint region with a spectral resolution of approximately 3 cm -1 within seconds. Microplastic particles composed of five common polymers—polypropylene, polystyrene, polyethylene, polyvinyl chloride, and polyethylene terephthalate—were accurately identified and spatially mapped. The method was further validated in mouse embryo tissue sections, where micrometer-scale microplastics were reliably distinguished against highly complex and spatially heterogeneous infrared backgrounds. This approach combines the intrinsic chemical specificity of infrared absorption spectroscopy with large field-of-view, high-throughput, and rapid imaging, enabling efficient in situ microplastic analysis in complex biological environments. • High-speed MIR hyperspectral imaging with sub-cycle pulses • Full MIR data cube acquired in seconds over mm-scale FOV • Reliable microplastic identification in biological matrices • Imaging-guided microscopic validation of μm-scale particles • Rapid chemical imaging workflow for microplastic screening