Well‐Aligned Hierarchical Design of High Strength Anisotropic Chitosan Fibers by Electrostatic Regulation for Absorbable Sutures

ABSTRACT Chitosan fibers prepared by conventional wet‐spinning methods result in significantly compromised wet‐state mechanical strength, attributed to hydrogen bonding that hinders molecular chain alignment. To address this critical challenge, this study develops an electrostatically regulated sacrificial micelle‐assisted alignment strategy to fabricate high‐performance anisotropic chitosan fibers for absorbable sutures. Utilizing sodium dodecyl sulfate (SDS) micelles, electrostatic regulation disrupts intermolecular hydrogen bonds in chitosan, enables uniaxial chain alignment during drawing, and reconstructs a dense hydrogen‐bonded network upon micelle removal with NaOH. The resulting pure chitosan fibers (Chit 0 ) exhibit exceptional mechanical properties, achieving a dry tensile strength of 293.6 ± 31.0 MPa and retaining 105.0 ± 17.2 MPa under wet conditions—significantly surpassing conventional wet‐spun chitosan fibers. Microscopically, the fibers exhibit aligned aggregates with reduced d‐spacings, effectively enhancing mechanical properties. The fibers demonstrate outstanding cytocompatibility, negligible in vivo inflammatory response, and controllable degradation kinetics (44% strength retention after 2‐week implantation). Animal experiments confirm accelerated wound healing with minimal scarring, outperforming commercial poly(glycolic acid) sutures in biocompatibility. This strategy offers a versatile paradigm for engineering anisotropic biopolymer fibers with balanced wet‐strength and biofunctionality.