The influence of surface chemistry on the control of cellular behavior: studies with a marine diatom and a wettability gradient

The marine diatom Amphora coffeaeformis is involved in biofilm formation on most illuminated marine surfaces, including ships and sediment particles. In sediments, cells of Amphora attach to sand particles and cause them to bind together. Although studies of the adhesion of diatoms to substrata as a function of differential surface chemistries have been published, none of these have used substrata where the differential surface properties are generated by the spatial packing of a single chemical of moiety. In this study, gradients of wettability on glass surfaces are generated by the relative proximity of covalently-bound methyl groups. Amphora is not motile on surfaces where the water contact was greater than 40 degrees, although cells do attach to these surfaces. Also, it appears that diatoms can increase the wettability of a surface during the course of an experiment. Furthermore, evidence is presented that Amphora produces a factor that causes dispersal of cells over a surface. Measurement of the speed of diatoms on a surface gives a good indication of the ability of the cell motility polymer to interact with that surface. (C) 1999 Elsevier Science B.V. All rights reserved.