Species-specific engineered antifouling topographies: correlations between the settlement of algal zoospores and barnacle cyprids

Abstract Abstract Novel, non-toxic antifouling technologies are focused on the manipulation of surface topography to deter settlement of the dispersal stages of fouling organisms. This study investigated the effect of the aspect ratio (feature height/feature width) of topographical features engineered in polydimethylsiloxane, on the settlement of cyprids of Balanus amphitrite and zoospores of Ulva linza. The correlation of relative aspect ratios to antifouling efficacy was proven to be significant. An increase in aspect ratio resulted in an increase of fouling deterrence for both zoospores and cyprids. The spore density of Ulva was reduced 42% with each unit increase in aspect ratio of the Ulva-specific Sharklet AF™ topography. Similarly, the number of settled cyprids was reduced 45% with each unit increase in aspect ratio. The newly described barnacle-specific Sharklet AF™ topography (40 μm feature height, aspect ratio of 2) reduced cyprid settled by 97%. Techniques have been developed to superimpose the smaller Ulva-specific topographies onto the barnacle-specific surfaces into a hierarchical structure to repel both organisms simultaneously. The results for spore settlement on first-generation hierarchical surfaces provide insight for the efficacious design of such structures when targeting multiple settling species. Keywords: Antifoulingbiofoulingsurface topographymicrotopographyalgaebarnacle Acknowledgements ABB, JAC, MEC and ASC all gratefully acknowledge the financial support of the Office of Naval Research (Contract No. #N00014-02-1-0325 to ABB, Contract No. #N00014-02-1-0521 to JAC & MEC and contract # N00014-05-1-0767 to ASC). Special thanks are to be given to Sean Royston for his technical assistance with the production and fabrication of the engineered topography and Sheelagh Conlan for assistance with cyprid culture.