Physicochemical mechanisms of microplastics adsorption by wheat bran insoluble dietary fiber in simulated intestinal fluid.

This study investigated wheat bran insoluble dietary fiber (WBIDF) as an edible adsorbent to mitigate intestinal microplastic (MPs) pollution. Combining in vitro simulations with in vivo mouse models, it elucidated WBIDF's adsorption mechanisms for MPs. Adsorption in simulated intestinal fluid was concentration-dependent and more effective for 1 μm versus 5 μm MPs (1.01 ± 0.05 and 0.83 ± 0.09 mg/g at a concentration of 50 mg/L, respectively), primarily via pore-filling and surface deposition. Spectral and computational analyses confirmed van der Waals interactions as dominant, with hemicellulose showing the highest affinity, with key sites involving ether bonds and hydroxyl groups in cellulose/hemicellulose, and aromatic rings in lignin via π-π stacking. In vivo intervention dose-dependently reduced intestinal MPs burden, alleviated systemic inflammation, and protected the colonic mucosal barrier in mice. The synergistic porous structure and components of WBIDF enable efficient MPs adsorption, establishing a foundation for edible strategies against gut MPs accumulation.