A multimodal imaging platform with Raman spectroscopy to disentangle the health risks of nanoplastic

Microscopic plastic particles and fibres ('microplastic'), originating from the degradation and wear of plastic materials, are a widespread pollutant in air, drinking water, food, and soils. There is potential for plastic to release even smaller particles - 1000 to 100,000 times smaller than a millimetre ('nanoplastic') - but this has not been confirmed in the environment due to a lack of available technology capable of such measurements. Nanoplastic is believed to be a greater public health threat than microplastic because it can enter cells and cause toxicity. Furthermore, nanoplastic will have longer lifetimes in air and water, before settling, and is therefore susceptible to long range transport, potentially around the globe. However, we have no idea on whether and how much occurs, or what it can do in environmental and biological contexts. We cannot understand what we cannot measure. This proposal aims to advance the analytical capacity in the UK, enabling the detection and characterisation of nanoplastic particles through the acquisition of a highly specialised imaging and microscopy platform. This will be achieved by two types of integrated microscopies, Atomic Force and Scanning Nearfield Optical Microscopy. Such a platform will also improve the detection of micro- and nanoplastic in samples, by exploiting plastic-specific properties through different types of light microscopy to highlight potential micro- and nanoplastic, thereby shortcutting where to direct further analysis. There are only a few platforms in Europe which integrate all these capabilities, none for the application of micro- and nanoplastics. This will be used to answer scientific questions on the prevalence, types, and toxicity of nanoplastics in air, human tissues, experimental cell models, and on the interactions between contaminants, microbes, cells, and micro- and nanoplastic. The data generated on the platform will impact industry and government, by indicating problem plastics for targeting innovative solutions and policy. The level of micro- and nanoplastic pollution is predicted to increase as plastic production continues to do so. It is therefore critical to start filling the huge gaps in our understanding of the impacts on health.

Plastic materials readily shed microscopic fragments (particles and fibres) known as microplastic. These have been detected in digested human stool, gut, and lung tissue, and plastic signatures have recently been detected in the blood of healthy volunteers, indicating bioaccumulation and distribution of inhaled and ingested microplastic in vivo. Combined with their ubiquitous presence in the environment, there is growing concern about their potential health impacts, although most measurements have been spatially limited to >1 um. Of great concern are the nanoscopic particles experimentally shown to be released under mechanical wear, as there is a greater likelihood for cellular interactions/toxicity and distribution beyond the gut and lung upon exposure. However, there is no available instrumentation with high enough spatial resolution and chemical sensitivity to measure nanoplastic. To maintain the UK's competitive edge, an enhanced capacity to do so is urgently required, to advance understanding of: 1) the pathogenicity of plastic in situ in the context of tissues and histology, and 2) population-level exposures through robust measurements in air and drinking water. We propose a unique imaging platform integrating Raman spectroscopy for chemical specificity with modal functionalities to expand the optical contrast of target micro-/nanoplastic in a sample, reducing analysis time from >5 h to ~2 h. Integrated near-field Atomic Force Microscopy and Scanning Nearfield Optical Microscopy will improve spatial resolution from ~1 um down to 200 nm and lower (~60 nm), respectively. The unique capability of the equipment - only offered from WITec - would be one of a few in Europe, the first in the UK. The configuration has been chosen for nanoplastic detection, but its applications are much broader. This maps to the core MRC research themes Population and systems and Molecular and cellular medicine, as well as the cross-cutting Population and public health sciences theme.