Engineered antifouling microtopographies: the role of Reynolds number in a model that predicts attachment of zoospores of Ulva and cells of Cobetia marina.

A correlation between the attachment density of cells from two phylogenetic groups (prokaryotic Bacteria and eukaryotic Plantae), with surface roughness is reported for the first time. The results represent a paradigm shift in the understanding of cell attachment, which is a critical step in the biofouling process. The model predicts that the attachment densities of zoospores of the green alga, Ulva, and cells of the marine bacterium, Cobetia marina, scale inversely with surface roughness. The size and motility of the bacterial cells and algal spores were incorporated into the attachment model by multiplying the engineered roughness index (ERI(II)), which is a representation of surface energy, by the Reynolds number (Re) of the cells. The results showed a negative linear correlation of normalized, transformed attachment density for both organisms with ERI(II) x Re (R(2) = 0.77). These studies demonstrate for the first time that organisms respond in a uniform manner to a model, which incorporates surface energy and the Reynolds number of the organism.