Hypothesising Systemic Resilience and Dynamic Recirculation of Nanoplastics: A Conceptual Biological Framework

The long-term biological fate of nanoplastics (NPs; <100 nm) in human tissues remains uncertain. Beyond acute toxicity, we propose a conceptual biological framework based on three interlinked pillars of host response: (1) biomolecular corona adaptation; (2) luminal biochemical–mechanical processing; and (3) a testable vascular-to-gastrointestinal (GI) recirculation hypothesis. This framework suggests that circulating NPs may undergo dynamic transit towards the GI tract, where mechanical shear and chemical degradation facilitate size reduction and surface erosion. Conversely, chronic entrapment in static compartments—such as the central nervous system parenchyma, fibrotic tissue, or atherosclerotic plaques—disrupts dynamic clearance. Luminal sequestration agents (i.e., Procambarus clarkii chitosan, PCC) represent potential exploratory proof-of-concept strategies to support elimination. This framework reframes systemic nanoplastic exposure from a static accumulation model to a dynamic physiological conversation. Specifically, we establish a conceptual biological framework that hypothesises three potential pillars of physiological response: (1) biocorona adaptability; (2) luminal chemical–mechanical processing capability; and (3) a testable vascular-to-GI recirculation hypothesis. According to this hypothesis, the migration of circulating particles in the path of the GI tract could act as an interacting physiological interface that promotes surface erosion and size reduction. This vascular-to-GI loop is proposed here as a viable hypothesis that requires quantitative mass-balance verification rather than an established physiological pathway. Conversely, this dynamic transit may be interfered with by chronic entrapment in static anatomical compartments, such as the brain parenchymal interstitium, fibrotic organ matrices, or atherosclerotic lesions.