Patterning of hydrophilic micro arrays with superhydrophobic surrounding zones

We present a simple method for the patterning of hydrophilic micro arrays with superhydrophobic surrounding zones. The hydrophilic areas with micro-pillars were obtained by standard photolithography and reactive ion etch of silicon dioxide or quartz plates, whereas the superhydrophobic microstructures were fabricated by casting poly-dimethylsiloxane on a two-level thick resist mold. It shows that the spotted water droplets can be fairly located in the hydrophilic areas because of the superhydrophobic areas repelling. We believe that such a substrate configuration will make it possible to obtain a new type of DNA chip substrates with increased signal-to-noise ratio and decreased cross contamination between the adjacent spot zones. The fabrication method proposed for the present prove-of-principle experiences is low cost and can be improved for mass production. (c) 2007 Elsevier B.V. All rights reserved.