Room-Temperature UV-Induced Self-Healing Hydrogels with Antifouling and Antiscratch Surfaces for Soft Contact Lenses

In this study, a dynamic disulfide-based cross-linker was synthesized and thermally copolymerized with 2-hydroxyethyl methacrylate (HEMA) to produce a self-healing hydrogel (DS-Hydrogel). The resulting hydrogel exhibited excellent recovery efficiency (up to ∼90%) under both elevated temperature and UV irradiation, as confirmed by tensile strength measurements. Remarkably, surface scratches were effectively repaired by simple UV exposure at room temperature (RT). Furthermore, contact lenses based on this hydrogel were fabricated, and 2-methacryloyloxyethyl phosphorylcholine (MPC), a zwitterionic monomer well known for its antifouling properties, was polymerized onto the lens surface through reactions with UV-generated thiyl radicals. This photoinduced surface functionalization with pMPC imparted improved resistance to nonspecific protein adsorption and further improved antiscratch performance. The MPC-grafted surface formed a lubricious and highly hydrated layer that effectively reduced friction and mechanical damage, thereby preserving optical transparency and surface integrity during practical handling. The engineered DS-Hydrogel was successfully integrated into pHEMA-based soft contact lenses, demonstrating a combination of high self-healing capability, durable antifouling behavior, and improved scratch resistance under physiologically relevant conditions.