Helical-cavity-preserving starch engineering enables root-inspired multilevel wet bioadhesion for corneal repair

Polysaccharide-based adhesives hold promise for wet tissue repair, yet their application is often limited by weak interfacial bonding and insufficient cohesive strength in hydrated environments. Here, we report a root-inspired multilevel wet bioadhesive enabled by helical-cavity-preserving starch engineering for corneal repair. Potato starch was sequentially succinylated and methacrylated under aqueous conditions to obtain methacrylate succinate diesterified starch (StaCMA), which retained the ability to form helical-cavity structures while introducing photocrosslinkable groups. When integrated with methacrylated gelatin, StaCMA formed a transparent hydrogel network that mimicked root-like anchoring through tissue-interpenetrating covalent fixation, branched-chain stress dissipation and helical-cavity-mediated polymer confinement. The optimized adhesive exhibited strong wet adhesion on human cornea, achieving a shear adhesion strength of 166 kPa and a burst pressure of 1286 mmHg, while maintaining visible-light transmittance above 90%. Iodine displacement, FTIR, NOESY, helix-denaturation controls and molecular dynamics simulations supported that starch helical cavities confined GelMA segments and promoted molecular association, thereby reinforcing both adhesion and cohesion. In ex vivo and rabbit corneal injury models, the adhesive enabled sutureless sealing of linear and irregular penetrating wounds and supported organized corneal regeneration with reduced fibrotic remodeling. This study establishes helical-cavity-preserving starch as an active carbohydrate-polymer motif for root-inspired wet bioadhesive design.