A Universal Polyelectrolyte‐Locking Strategy: From Common Proteins to Stable Unfolded Protein‐Based Adhesives for Rapid and Robust Tissue Sealing

Marine protein adhesives present robust wet adhesion by mediating interfacial interactions through surface-exposed hydrophobic domains/adhesive groups and maintaining cohesive networks via intrinsically disordered protein structures. Replicating these capabilities in common protein systems remains challenging, especially in stabilizing hydrophobic residues at interface and improving cohesive properties. Here, we developed unfolded protein-based adhesives via a universal strategy of locking with polyelectrolytes that have flexible long chains and high charge density. These polyelectrolytes simultaneously stabilize exposed hydrophobic residues on the unfolded proteins and reinforce cohesion properties via chain entanglement with electrostatic/hydrogen bonding interactions. The unfolded bovine serum albumin (UBSA) and polyacrylic acid (PAA) are integrated to prepare a representative tissue adhesive (UBSA-PAA), exemplifying the polyelectrolyte-locking strategy. The UBSA-PAA adhesive demonstrated interfacial hydrophobicity (water contact angles >90°) and excellent adhesion performance on wet tissue. In severe liver and femoral artery hemorrhage models, this adhesive significantly reduced blood loss compared to commercial fibrin glue, while maintaining comparable biocompatibility. This polyelectrolyte-locking molecular engineering strategy provides a universal framework for designing protein-based adhesives with excellent wet adhesion performance.