Overview
- Researchers at Tokyo University of Science engineered irregular nano-microplastic fragments from PET, PP, PE, and PS that emit in the NIR-II window after loading with dyes such as IR-1061 and Nile red.
- The particles measured about 30–300 nanometers, were water-dispersible, and retained more than 80% of their fluorescence for at least 30 days.
- In orally dosed mice, fluorescence remained confined to the stomach and intestines before fecal excretion, with no detectable signals in other organs under these conditions.
- Particle size influenced intestinal residence time, with polypropylene particles under 100 nanometers persisting longer than larger counterparts.
- In vitro tests showed mouse fibroblasts internalized the irregular tracers at concentrations as low as 2.0 µg/mL, and the authors call for longer-term and route-specific studies to translate findings to human health.