In situ protein synthesis on glass substrate with acoustic microdroplet ejector with air-cavity lens formed by micromachined silicon

This paper describes protein synthesis with 200 pL peptide droplets that are ejected onto a glass substrate by a new acoustic droplet ejector based on Fresnel lens of air cavities formed through micromachined silicon. The ejector uses a newly developed Fresnel air-cavity lens made with micromachined silicon. The new design simplifies the fabrication process, and has a better yield than the parylene-based air-cavity lens. With the fabricated ejector, synthesis of glycine was demonstrated using fmoc chemistry resulting in 96% stepwise coupling yield and 70% net efficiency for 9-mer-long peptide. Usage of acoustic droplet ejector increases the density of protein array on a chip.