Effects of surface texturing on microalgal cell attachment to solid carriers

The objective of this study was to understand the role of surface texturing in microalgal cell attachment to solid surfaces. Two microalgal species, Scenedesmus dimorphus and Nannochloropsis oculata, were studied on solid carriers made of nylon and polycarbonate. Ridge, pillar and groove at micro-scale were engineered on the solid carriers. Cell response to the textured surfaces was separately described by the Cassie and Wenzel models and the contact point theory. Comparison between measured and model-predicted contact angles indicated that the wetting behavior of the textured solid carriers fell into the Wenzel state, which implied that algal cells could fully penetrate into the designed textures, but the adhesion behavior would be dependent on the size and shape of the cell. Experimental results showed that the attachment was preferred when the feature size was close to the diameter of the cell attempting to settle. Larger or smaller feature dimensions had the potential to reduce cellular attachment. The observation was found to qualitatively comply with the contact point theory.