Substrate-Specific Formation of Barnacle Adhesive

It is very well known that the type into which a cell is differentiated is determined by the interaction of the cell surface with its (macro) molecular environment (e.g.. Refs. [19, 20]). It is shown below that the supramolecular structure of barnacle adhesive, which is an extracellular matrix, is also formed through surface interactions. 

Barnacles usually produce an even base plate that nestles against the substrate surface. However, barnacles that were loosely attached to PDMS coatings produced cup- or funnel-shaped base plates filled with a hydrated adhesive plaque. Cross-sections through the barnacle base viewed with a light microscope revealed that the adhesive plaque was a multilayered system, in which the density of the adhesive layers decreased consecutively toward the substrate (Fig. 10.2). 

However, the barnacles were not able to crack the PDMS coating. It was assumed that the adhesion strength was too weak to hold the barnacles in place while the parietal plates exerted downward pressure onto the substratum [2]. Consequently, the loosely attached barnacles were lifted, and due to the horizontal and downward apposition of lime the base plates grew into cup shapes. 

If a barnacle lifted itself, the freshly released adhesive would consequently flow into the emerging space. A series of such events would cause the adhesive to be built up layer by layer (see the scheme in Fig. 10.4 for the deformation of the barnacle base and the location of adhesive secretion). 

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