Replacing petroleum-based synthetic fibers with sustainable bio-derived alternatives has long been recognized as a critical pathway to mitigating global microplastic pollution, but the practical use of biomass fibers has long been limited by their insufficient mechanical performance. Now, writing in the journal Science Bulletin , a joint research team from Anhui Agricultural University and Zhejiang University presents a breakthrough solution. Their bioinspired hydrodynamic twisting strategy creates cellulose metafibers (Meta-CFs) with unprecedented strength and toughness, offering a high-performance, fully biodegradable alternative to conventional synthetic fibers.
The Performance Gap: Natural Potential vs. Practical Limits
Cellulose is the most abundant natural polymer on Earth, with crystalline domains boasting a theoretical strength exceeding 7 GPa. Yet conventional regenerated cellulose fibers suffer from an inherent trade-off between strength and toughness. Defect accumulation and disordered molecular packing during spinning typically limit their tensile strength to below 3 GPa, restricting them to low-demand textile uses rather than heavy-duty structural applications.
Bioinspired Blueprint: Engineering a Microfluidic Twist
Drawing inspiration from the twisted hierarchical keratin structure of rhinoceros horns—a natural design that delivers exceptional impact resistance—the research team developed a scalable hydrodynamic twisting spinning method. Using an asymmetric microfluidic field, the technique applies precise torque to the flowing cellulose solution, forming continuous, uniform twisted architectures on the fiber. A chemical and physical network simultaneously locks these ordered structures in place, drastically suppressing defect accumulation as the fiber solidifies.
Defect Suppression Drives Ultimate Strength and Toughness
Multiscale experiments and molecular dynamics simulations confirm that the twisted architecture drives efficient stress delocalization and cooperative load transfer across the entire fiber. Under optimized conditions, the resulting Meta-CFs achieve a maximum tensile strength of 3.29 GPa and a toughness of 349.5 MJ m –3 . This rare combination puts their strength on par with top-tier synthetic fibers and their toughness on par with natural spider silk—a performance benchmark never before reached by biomass-derived regenerated cellulose fibers.
Scaling Up: Constructing High-Load Integrated Bundles
To translate laboratory performance into real-world applications, the team developed a practical upscaling approach. By coating bundles of individual Meta-CFs with calcium alginate and cross-linking the surface, they created larger-diameter fiber bundles that retain GPa-level tensile strength while preventing inter-fiber slippage. Critically, the all-biomass composition remains fully biodegradable.
The team validated the material’s practical value by fabricating scaled-up Meta-CFs into trimmer lines for lawn and vegetation maintenance. In 30-minute cutting tests, the bio-based trimmer lines showed wear resistance comparable to commercial nylon trimmer lines, with similar mass loss during operation. The striking difference lies in environmental impact: while nylon trimmer lines shed microplastic fragments that persist indefinitely in soil, Meta-CF trimmer lines and their wear debris fully biodegrade within 49 days, leaving no lasting environmental footprint. The findings offer a viable material-level solution to agricultural microplastic pollution, and provide a generalizable framework for engineering high-performance sustainable polymer fibers.
Science Bulletin
Experimental study