Single-molecule study of the synergistic effects of positive charges and Dopa for wet adhesion
Using AFM based single-molecule force spectroscopy, we studied the synergy between Dopa and lysine for wet adhesion on titania (TiO2) and mica surfaces. We found that the binding forces for lysine–Dopa dipeptides are significantly higher when the positive charge of lysine is unprotected on both surfaces. However, such a synergistic effect is absent when the sequence is reversed. We attribute such differential synergistic effects to their distinct structure for load distribution within the molecules, which may represent a general principle for synergistic strong adhesion.