Controlling the Cassie-to-Wenzel Transition: an Easy Route towards the Realization of Tridimensional Arrays of Biological Objects

In this paper we provided the evidence that the Cassie-to-Wenzel transition can be exploited\r\nas an effective micro-fabrication strategy to obtain highly ordered three-dimensional (3D) arrays of biological\r\nobjects. To this purpose we fabricated a patterned surface wetted in the Cassie state where we deposited a\r\ndroplet containing genomic DNA.We found that, when the droplet wets the surface in the Cassie state, an array\r\nof DNA filaments pinned on the top edges between pillars are formed. Conversely when the Cassie-to-Wenzel\r\ntransition occurs, DNA can be pinned at different height between pillars. These results open the way to the\r\nrealization of 3D array of biological objects