The goal of this project is to understand wet biological adhesion upon which to develop biologically inspired adhesives. Common experience tells us that adhesives and water do not mix: interfacial water constitutes a barrier to strong surface bonding, hampering the effectiveness of most synthetic adhesives. This is an even more serious problem for medical sealants when considering about their need in liquid stability to water or bodily fluids so that their adhesion properties are not significantly affected by fluids over the period of use. Therefore, there is an urgent desire to develop new biocompatible and water resistant adhesives for medical applications. While gluing wet surfaces or even under water remains a major challenge, mussels, on the other hand, have it worked out via a secretion of protein mixtures (byssus) to attaching firmly to underwater surfaces. Initial studies have pointed out the definite role of 3,4-dihydroxyphenyl-L-alanine (Dopa) residue during mussel adhesion process and Dopa containing polymers have been the paradigm of mussel inspired adhesives. However, interesting yet unexplored topic is the contribution from residues other than DOPA in mussel adhesion especially on different surface chemistries. Therefore, the objectives of this study were to investigate how protein-surface interaction effects are influenced by surface chemistries and how these effects combine with the protein-protein interactions upon a mussel adhesive protein to influence its structure and corresponding peptide mappings at adsorbed state. 

In this project, the amino-acid labeling/mass spectrometry (AA/Mass) technique was used to investigate the configurations of a protein at adsorbed status, especially its dominant peptide mappings on each selected surfaces including silicon and polymer. Finally, Atomic Force Microscopy (AFM) will be applied to pull a single polymer chain containing these aminoacids residues from previous mapping results on a selected surface in wet environment, using an AFM tip to measure the desorption force involved, with these findings being able to reveal direct proofs of the efficiency in wet-resistant adhesive polymer designs. Results in this project should then provide the molecular-level understandings of mussel adhesions on different surface chemistries and most importantly, to help the development of better mussel inspired adhesives.