Effects of Physical Parameters on Structural Maturation of Marine Mussel Adhesive Plaques*

Marine mussels have evolved to produce extremely effective wet adhesives. In order to create synthetic versions of these adhesives, we would like to understand the division between the biological and physical parameters involved in their formation and structural maturation. Mussel adhesives exist as acellular, thin films, known as plaques, consisting of mussel foot proteins (mfps). In the case of Mytilus californianus, cross-linked mfps form a foam architecture that incorporates iron and calcium. The origin and role of iron and calcium, among other metals, in the structural maturation process is unknown. Using electron microscopy, inductively coupled plasma mass spectrometry, and amino acid analysis, we examine the composition, the effect of iron and calcium, and the role of pH on the time evolution of the plaque’s maturation. Our results suggest that physical, rather than biological, processes are critical to the formation of the final structure.