Lab-on-a-chip systems for microplastic and nanoplastic sampling, detection, characterization and bioassessment

Microplastics and nanoplastics are ubiquitous environmental contaminants, with growing evidence of their ecological and human health risks. However, a clear understanding of their impacts remains limited due to challenges in isolating MPs/NPs from complex environmental and biological matrices, insufficient sensitivity at the submicron scale, lack of standardized testing protocols, and inconsistent biological outcomes arising from variability in particle properties and cell models. Lab-on-a-chip (LoC) systems offer an integrated solution by combining automated sample handling, on-chip particle enrichment, multimodal characterization, and physiologically relevant culture models under controlled microenvironments. This review first examines current analytical techniques for MPs/NPs, followed by a detailed analysis of state-of-the-art LoC strategies for particle sampling, detection, characterization, and biological impact assessments. From filtration and density-based separation for sample preparation to advanced on-chip enrichment and detection techniques such as surface-enhanced Raman spectroscopy (SERS)-coupled microfluidic platforms, we evaluate the strengths and weaknesses of each approach, identify analytical bottlenecks, and provide directions for system integration to improve sensitivity, specificity, and throughput. For biological impact evaluation, we compare 2D monolayers, co-cultures, organoids, and organ-on-a-chip models, highlighting sources of experimental variation and providing guidelines for improved reproducibility and relevance. Ultimately, we aim to outline future directions for leveraging the advantages of LoC systems to enable high-throughput, standardized and meaningful ecological analysis of MPs/NPs, advancing their potential for long-term environmental monitoring of plastic pollution as well as human toxicity screening and health impact assessment.