Liquid loading of silicon-based cantilevers using electrowetting actuation for microspotting applications

An array of silicon-based cantilevers that can be actively loaded with liquid solutions was designed and fabricated for spotting applications. Each cantilever incorporates a slit and a reservoir for liquid storage, and droplet formation occurs by direct contact deposition. The loading scheme, based on the use of continuous electrowetting, was implemented either by patterning metallic electrodes inside the channel or by doping the silicon tip with phosphorus. Fabricated devices were tested using DMSO and water-glycerol solutions. DC voltage as low as 30 V was used to load the cantilevers, and matrices of 20 μm diameter droplets were successfully patterned.