Patterned, high surface area substrate with hydrophilic/hydrophobic contrast, and method of use

Nanoporous structures are constructed that have hydrophilic regions separated by hydrophobic regions. The porous, hydrophilic regions have reaction sites suitable for use in a bioassay application and have a higher density of reaction sites than that of a non-porous (2-D) surface. The structure may be made by depositing a layer of a matrix material (e.g., an organosilicate) and a porogen, and then crosslinking the matrix material to form a nanohybrid composite structure. The porogen is decomposed to form pores within the matrix material, and a reactive gas phase species (e.g., ozone) is patternwise directed onto a surface of the matrix material. Ultraviolet light (directed through a mask) activates the gas phase species to form a reactive species that then reacts with the matrix material to make it hydrophilic. The porogen may be decomposed thermally or by exposing it to an oxidizing atmosphere in the presence of ultraviolet light.