A comparative review of organ-on-a-chip technologies for micro- and nanoplastics versus other environmental toxicants

In recent years, organ-on-a-chip (OOC) technology has emerged as a groundbreaking platform to simulate complex physiological processes. Concurrently, the global presence of micro and nano-plastics (MNPs) in the environment and their ingestion has raised concerns about their impact on human health, specifically organs such as the lungs, liver, kidneys, and blood vessels. There is an added concern about their ability to cross even the blood-brain barrier (BBB). While numerous papers have been published assessing various environmental toxicants with OOCs, those for MNPs are relatively small. To ascertain current trends in methodologies and catalog the types of toxicants explored, we have gathered and analyzed papers that used OOCs to assess various environmental toxicants' impacts on these organs. Various platforms assessing MNPs were analyzed and compared to those for other environmental toxicants. Our results show that few articles have been published that used OOCs to assess MNPs' toxicity to human organs. Specifically, certain organs, such as the heart and skin, have little representation in this collection. OOC-based evaluation methods for MNP's toxicity have many advantages over the current methods – in vitro tests with 2D human cell cultures and animal studies – including lower cost, faster results, and greater physiological relevance. This review summarizes the current OOC techniques for assessing environmental toxicants and laboratory methods for evaluating MNPs' toxicity to humans. A systematic comparison of these methods provides a deeper understanding of the current techniques and suggests the optimized use of OOCs for assessing MNPs' and other pollutants' toxicity.