Charge-Conversion-Induced\nComplexation Toughening\nof Adaptive and Degradable Protein Optical Fibers for Interventional\nCancer Therapy

Protein hydrogel fibers hold great promise for diverse\napplications.\nHowever, the challenge lies in developing rapid and straightforward\nmethods for the one-step fabrication of high-performance protein-based\nhydrogel optical fibers. Here, we present a general charge-conversion-induced\ncomplexation toughening (CCICT) strategy for preparing protein hydrogel\nfibers in 15 s. The in situ introduction of polyelectrolyte–micelle\ncomplexes enhances the fibers’ mechanical, antiswelling, and\nantibacterial properties. The protein components confer biocompatibility,\nenzymatic degradability, and strong tissue adhesion to the hydrogel\nfibers. Furthermore, the as-prepared fibers demonstrate excellent\noptical transmission with minimal attenuation of 0.15–0.50\ndB cm<sup>–1</sup> across various wavelengths. The hierarchical\nmultinetwork structure imparts outstanding adaptability and stability\nin mechanical and optical performance. Also, the protein fibers effectively\ndeliver light for interventional photothermal cancer therapy beneath\nthe skin of mice. Their rapid degradation in physiological environments\npromotes efficient wound healing. Therefore, this developed CCICT\napproach and these high-performance protein fibers are anticipated\nto have broad applications.