Morphological and chemical characterization of nanoplastics in human tissue

Micro- (≤ 5 mm) and nano- (≤ 1 µm) plastics have become ubiquitous resulting in inevitable human exposure. Evidence exists of mass-based accumulation of plastic in human tissues with visualization of micron-sized particles (> 1 µm). To date, there is little evidence to address accumulated nanoplastics. Understanding internalized plastic particle morphological and chemical characteristics is essential to facilitate proper design of future mechanistic and controlled exposure health effects studies to determine whether any health-related risks exist. Here we show microscopic evidence and quantitative dimensional analysis of nanoplastics in human decedent brain, kidney, and liver tissues. Mean particle lengths (nm) across the five decedents were 171.2±4.6 for brain, 124.4±3.6 for kidney, and 147.6±6.6 for liver. Mean particle widths (nm) were 45.9±1.5 for brain, 32.3±0.7 for kidney, and 36.1±1.3 for liver. When examining the aspect ratio, 78-83% consisted mostly of an elongated nanometer sized fiber morphology. The study provides isolation with physical and chemical characterization of nanoplastics in human tissues. Interestingly, differences were greater between tissues of a single decedent than across decedents. Consistently, the nanoplastics were largest in the brain. The observations overall suggest specificity with respect to systemic internalization and subsequent tissue accumulation of plastic particles less than one micron.