Diagnostic devices are disclosed which contain porous material. The porous material preferably comprises silica and alumina. Chemical and/or biological molecules can be bound to the porous material in high concentrations while both having high accessibility to molecules in solution, and retaining their natural conformation. Such diagnostic devices may be used for a wide array of assays including protein (e.g. ELISA) and nucleic acid (e.g. hybridization on chips or beads) detection and/or quantification methods.