Kinetic-Locked Fiber Networks Enable Anti-Fouling, Mechanically Robust Zwitterionic Hydrogels

Zwitterionic hydrogels possess exceptional antifouling characteristics and biocompatibility, but their weak mechanical strength limits implantable applications. Existing enhancement strategies either introduce non-zwitterionic phases that compromise antifouling performance or employ zwitterionic fillers that still fall short of achieving high mechanical robustness. Here, we present a kinetic-locking strategy to fabricate strong, antifouling zwitterionic composite fibers for hydrogel reinforcement. Co-dissolving hydrophilic zwitterionic and hydrophobic polymers followed by electrospinning kinetically traps molecular entanglement via ultrafast solvent evaporation, suppressing thermodynamic phase separation. The kinetically preserved molecular entanglement maintains the antifouling properties of the zwitterionic component while enabling the hydrophobic polymer to contribute substantial mechanical strength. In addition, the entanglement and electrostatic interaction between the fibers and the zwitterionic matrix form a robust interface for efficient load transfer. This approach is broadly applicable across polymer systems, producing hydrogels that integrate high tensile strength (2.48 MPa), extreme stretchability (1040%), and remarkable fracture toughness (27.76 kJ m^-2-a three-order-of-magnitude improvement over pure zwitterionic hydrogels) without sacrificing antifouling properties. These advances support reliable long-term in vivo electromyography recording and effective sciatic nerve stimulation. The work establishes kinetic locking as a general design paradigm to overcome the strength-antifouling trade-off in zwitterionic hydrogels, advancing durable, long-term implantable bioelectronics.