Nanoplastic Translocation Across Biological Barriers (Blood-Brain, Placental, Intestinal): Transport Mechanisms, Tissue-Specific Vulnerabilities, and a Corona-Driven Barrier Selectivity Framework.
Level 5 - mechanism / opinion, no new human data
Narrative review and conceptual framework synthesizing mechanistic preclinical literature.
PubMed 42510681 · doi:10.3390/biology15141133
What was done
This narrative review synthesized literature on nanoplastic (≤1 µm) translocation across three major biological interfaces: the intestinal epithelium, the blood-brain barrier, and the placental syncytiotrophoblast. The authors categorized findings across evidence tiers (detection, association, mechanism, causality) and model systems (in silico, in vitro, ex vivo, animal, human) while introducing a conceptual model termed corona-driven barrier selectivity (CDBS).
What was found
The abstract reports no primary quantitative outcomes or pooled effect estimates. It identifies reported transport mechanisms including clathrin- and caveolin-mediated endocytosis, reactive oxygen species (ROS)-induced tight-junction breakdown with paracellular leakage, receptor-mediated transcytosis, and candidate olfactory pathways. It notes that most published mechanistic work utilizes pristine polystyrene beads at concentrations 3 to 6 orders of magnitude above plausible human exposure levels.
Why it matters
It organizes the mechanisms of nanoplastic translocation around the surface biomolecular corona rather than bare polymer chemistry, while highlighting the substantial translational gap between experimental models and real-world human toxicity.
Limits
The proposed CDBS model is theoretical and requires experimental validation. Primary studies synthesized in the review largely use uniform pristine polystyrene beads that fail to reflect complex, weathered environmental mixtures. Dose exposures in reviewed experiments exceed human exposure estimates by 1,000- to 1,000,000-fold, current detection tools substantially underestimate sub-micrometre particles in human tissue, and causal links to human clinical pathology remain unestablished.
Cited by
- supports Nanoplastics smaller than 1 micrometer can cross the blood-brain barrier.
- supports Nanoplastics can cross biological barriers and enter the systemic bloodstream.