Peptidyl Biomimetic Adhesives via Sequential Isomerism-Dictated Physical Condensation and Underwater Adhesion

Physical condensation of oligopeptides provides a reductionist platform for probing the underwater adhesion of marine adhesive proteins. The link between peptide sequence and adhesion remains unclear at the molecular level. Using cationic peptide isomers and anionic H₄SiW₁₂O₄₀ (SiW) clusters, we explored how sequence isomerism governs the adhesion of the peptide/SiW condensates via regulating the layout of two lysine residues within the peptide isomers. On stainless steel (SS), one-end-on isomers with lysine residues at one terminal exhibited adhesion strengths of 43.1-54.2 kPa; end-side-on isomers with lysine residues at both terminals and midsite yielded adhesion of 64.1-67.8 kPa; while double-end-on isomers with lysine residues at both termini achieved adhesion strength of 74.4-87.1 kPa. Furthermore, introducing one glutamic acid residue enables protonation-/deprotonation-driven charge redistribution and adhesion regulation. This work establishes a design principle, whereby the adhesion of peptide condensates can be controlled by optimizing binding site arrangements in peptide sequences.