Barnacle adhesive properties

Bioadhesives may basically consist of proteins, polysaccharides, polyphenols, and hpids. These substances occur mostly in combination. The adhesives of the well-studied blue mussel Mytilus edulis) and of barnacles are proteinaceous materials. Other well-known proteins with adhesive properties are elastin, collagen, fibronectin, laminin, fibrinogen, and keratin. 

The consideration outlined above agrees with the assumption that substrates influence the structure formation of barnacle adhesive indirectly via properties that hold the barnacle base at a distance from the surface (e.g., fiber coatings, thick biofilm layers) or cause large interfacial gaps (e.g., PDMS coatings). These factors affect the concentration in the dispersion, and hence the position on the adsorption isotherm as compared to the micellar or hemi-micellar concentration, by impinging on the interfacial volume that needs to be filled with adhesive. 

From the evolutionary point of view, structures or mechanisms that prove a success are likely to be passed on. However, adult barnacles probably do not control the structure formation process of their cement The ability of cypris larvae to sense physical and chemical surface properties most likely vanishes after attachment and metamorphosis, for the main function of the adult is to feed and to metabolize the energy into growth and reproduction. Instead, the above observations probably suggest that the structure formation process is simply a result of water uptake increasing the effective size of the adhesive filling spaces or gaps. 

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