Magnetically Assisted Tracking of Micro- and Nano-Plastics: Advances in Materials and Devices for Enhanced Spatial and Temporal Resolution

The widespread use and long-term exposure of humans to micro- and nano-plastics (MNPs) drives a significant need to comprehensively understand their health impacts. MNPs have now been definitively detected in a multitude of environmental, as well as human biological samples, confirming that they do in fact enter and accumulate in the human body. However, there are still significant challenges when it comes to understanding the interaction between MNPs and human physiology. The complex combinations of particle size, shape, and chemical composition – including polymer type and additives/contaminants – and how such combinations interact with a multitude of human biological environments, makes it difficult to determine clear and precise exposure-effect relationships. Furthermore, in light of growing research showing that the identification and quantification of MNPs in vivo may have been inaccurate due to strong background signals, calls for the development and implementation of additional technologies have been emerging. In response to this, we have been exploring the possibility of utilizing magnetic nanoparticles (often in combination with fluorescent detection) to shed further light on the spatial and temporal detection of MNPs. Over the past two decades, a battery of novel technologies, that permit detection with breadth, depth, detail and completeness never explored before – have been developed, offering track-and-trace information at macro-, micro- and nano- perspectives. This review (i) provides the current status of prevalence of micro- and nano- plastics in the environment and in living organisms, (ii) gives an overview of the physiological negative impact on humans, (iii) summarizes the current detection and quantification methodologies along with the challenges and blind spots, and (iv) proposes novel techniques and instrumentation using magnetic nanoparticles that will provide unprecedented spatial- and temporal- resolution of the whereabouts of MNPs. It is our hope that through this, the MNP community will continue to have fruitful discussions on how best to attack the current problems.