Optical, Chemical, and Biological Detection Methods of Microplastics and Nanoplastics

Microplastics and nanoplastics (MNPs) are pervasive environmental contaminants with major impacts on ecosystems and human health. This raises the need to accurately detect and characterize MNPs to understand their sources, transport, fate, and biological effects. However, MNP sensing remains challenging due to their small size, chemical diversity, and complexity of environmental matrices. Here, we review recent advances in optical, chemical, and biological detection methods for MNPs as of Jan 2026 while comparing their strengths and limitations. Optical approaches, such as light microscopy, electron microscopy, and light scattering techniques, provide insights into size and morphology. Next, chemical detection, including FTIR, Raman spectroscopy, and mass spectrometry, enables quantitative and qualitative assessments of polymer types. Lastly, emerging biological strategies employ microbial biosensors and biomolecular probes for cost-effective, rapid, and in situ MNP detection. We also explore novel MNP-sensing methods and propose future directions for integrated and standardized MNP detection frameworks to support environmental monitoring and risk assessment.