Clinical infusion bypasses physiological barriers to directly deliver microplastics into human circulation

Intravenous infusion bypasses physiological barriers, directly introducing microplastics (MPs) into the bloodstream. Cleanroom simulations revealed MPs concentrations of 211 ± 34 (0.9% NaCl) and 179 ± 28 MPs/L (5% glucose), mostly < 20 µm in size, plus with 4–5 µg/L nanoplastics. Predominantly polyamide and polyvinyl alcohol, matching infusion materials. A 5-day infusion delivers > 1000 particles - equivalent to months of inhalation/ingestion exposure. This overlooked medical route necessitates safer materials and regulation.