Adhesives are commonly used throughout our daily lives to glue objects together and of the many types available, there exists a category of adhesives called bioadhesives. These natural polymeric materials, such as mussel adhesive proteins, have garnered great interest because they tend to be biocompatible and can be used for biomedical applications involving skin or other tissues.

A team of researchers with the Department of Chemical Engineering at Pohang University of Science and Technology (POSTECH), led by Professor Hyung Joon Cha, has now identified the mechanism by which Dopa-Fe³⁺ complexation affects surface adhesion and cohesion of mussel adhesive proteins at the interface. Through their research on responses to microenvironment at the mussel plaque/substrate interface, they have discovered how mussels regulate Dopa functionality as a response to differing pH concentrations in order to strengthen surface adhesion and cohesion.

Depa-Fe³⁺ complexation has been known to play an important role in mussel adhesion through adhesive proteins, but its function at the plaque/substrate interface, where actual surface adhesion occurs, remained a mystery. The research team investigated the effects of Dopa-Fe³⁺ complexation on underwater cohesion and surface adhesion by measuring cohesive and surface adhesive interactions using surface forces apparatus. They discovered that the strong surface adhesion present at low pH levels—similar to the environment present during the secretion of adhesive proteins—vanishes through Dopa-Fe³⁺ complexation and alternatively, strong cohesion is generated at higher pH levels similar to seawater.

Professor Cha explained that this discovery is an important step towards a deeper understanding of the mussel adhesion mechanism. He also expressed great anticipation for applications of the findings to the development of new bioadhesives.

This research received financial support provided by the Marine Biotechnology program (Marine BioMaterials Research Center) funded by the Ministry of Oceans and Fisheries, Korea, and was recently published in Chemistry of Materials—a preeminent journal in the chemistry field.