Toughening Artificial Spider Silk via Glue-Like Nanoparticle Crosslinks

Natural spider silk achieves its exceptional performance through the synergy of rigid β-crystallite anchors and stretchable, energy-dissipating β-sheet domains. However, perfectly replicating this architecture in biomimetic systems remains a significant challenge. Here, we report the development of super-tough artificial silk fibers utilizing a hybrid covalently anchored network (CGN) architecture based on bioinspired glue-like nanoparticles (GNPs). By integrating these GNP cross-links into a stable covalent network, we created a system where adsorbed polymer chains on the GNPs form dynamic loops with substantial hidden lengths. Upon stretching, these loops unfold and dissipate massive energy via the sacrificial rupture of interfacial bonds, mimicking natural β-sheet domains. Crucially, adjusting GNP cross-link size and interfacial binding strength enables precise tuning of the fiber's mechanical balance. Furthermore, the stable covalent skeleton serves as a topological anchor, imposing entropic penalties on chain desorption. This constraint suppresses polymer detachment from the GNP surfaces, compelling chains to undergo stress-induced orientation and assemble into highly aligned nanofibrils. The resulting fibers achieve a tensile strength of 1.25 GPa and a toughness of 306 MJ m^-3, successfully reproducing the strength-toughness synergy of native silk. This approach offers a scalable pathway for engineering high-performance fibers for applications in artificial muscles and advanced actuators.