The design and testing of a silica sol–gel-based hybridization array

Abstract An approach for building DNA hybridization arrays has been developed, in which silica aquogel arrays are produced using micropiezoelectric printheads. When supercritically dried, the pads in these gel arrays have a footprint size of 0.4 ± 0.1 mm in diameter in which the porous silica has a density of 0.045 g cm −3 , pore diameters ranging between a few nanometers and 0.5 μm, and internal surface areas >800 m 2 g −1 (5 × 10 −4 m 2 per pad). This enormous internal surface area, combined with reasonable accessibility to internal binding sites, makes aquogel pads ideally suited for hybridization arrays. Silanized probe DNA was immobilized within the gel pads during gelation, and hybridization was carried out with fluorescently labeled target DNA. The array sites containing probe DNA and the control sites without probes are readily distinguishable using laser-assisted fluorescent scanning.