Resolving Non-Specific and Specific Adhesive Interactions of Catechols at Solid/Liquid Interfaces at the Molecular Scale.

Utzig, Thomas; Stock, Philipp; Valtiner, Markus

The adhesive system of mussels evolved into a powerful and adaptive system with affinity to a wide range of surfaces. It is widely known that thereby 3,4-dihydroxyphenylalanine (Dopa) plays a central role. However underlying binding energies remain unknown at the single molecular scale. Here, we use single-molecule force spectroscopy to estimate binding energies of single catechols with a large range of opposing chemical functionalities. Our data demonstrate significant interactions of Dopa with all functionalities, yet most interactions fall within the medium-strong range of 10-20 kB T. Only bidentate binding to TiO2 surfaces exhibits a higher binding energy of 29 kB T. Our data also demonstrate at the single-molecule level that oxidized Dopa and amines exhibit interaction energies in the range of covalent bonds, confirming the important role of Dopa for cross-linking in the bulk mussel adhesive. We anticipate that our approach and data will further advance the understanding of biologic and technologic adhesives.

MUSSELS; SOLID-liquid interfaces; CATECHOL; ADHESIVES; MOLECULAR physics; NANOTECHNOLOGY

Angewandte Chemie, 2016, Vol 128, Issue 33, p9676

0044-8249

Academic Journal

10.1002/ange.201601881