Bioinspired Hierarchical Cellulose/MXene Fibers for Integrated Capture and Ultrasensitive Detection of Microplastics in Complex Biological Matrices.

Abstract

The long-standing disconnection between enrichment and identification processes fundamentally limits the reliable tracing of microplastics (MPs) in complex aqueous and biological environments. Inspired by the synergistic structure-function design of bee leg villi, we report a bioinspired hierarchical fiber composed of tunicate nanocellulose (TNC) and PDDA-modified positively charged MXene (P-MXene) that seamlessly integrates active capture with molecular identification. Through microfluidic spinning combined with interfacial electrostatic engineering, the hierarchical fiber is endowed with a biomimetic wrinkled topology and a rationally designed positively charged architecture, enabling spontaneous sequestration of negatively charged MPs with an ultrahigh adsorption capacity of 978.9 mg/g, a 9-fold enhancement over pristine fibers. Concurrently, the MXene-functionalized surface serves as an efficient surface-enhanced Raman scattering substrate, delivering an enhancement factor of 1.2 × 10⁵ and enabling a 128-fold improvement in detection sensitivity. Benefiting from this integrated trap-and-sense mechanism, the platform effectively suppresses interference from complex biological matrices and enables trace-level detection of MPs accumulation in plant tissues, such as bean sprouts, revealing preferential retention in the root systems. This work establishes a versatile biomimetic hierarchical fiber-based material platform for detecting trace-level contaminants in realistic biological systems and beyond.