Method of making biochips and the biochips resulting therefrom

Abstract

Methods for preparing a biochip are provided herein wherein the biomolecular probe to be used with the biochip is alternatively bound to a hydrogel prepolymer prior to or simultaneously with polymerization of the prepolymer. In particularly preferred embodiments, a polyurethane-based hydrogel prepolymer is derivatized with an organic solvent soluble biomolecule, such as a peptide nucleic acid probe in aprotic, organic solvent. Following derivatization of the prepolymer, an aqueous solution, for example sodium bicarbonate, preferably buffered to a pH of about 7.2 to about 9.5, is added to the derivatized prepolymer solution to initiate polymerization of the hydrogel. Alternatively, a water soluble biomolecule, such as DNA or other oligonucleotide, is prepared in an aqueous solution and added to the polyurethane-based hydrogel prepolymer such that derivatization and polymerization occur, essentially, simultaneously. While the hydrogel is polymerizing, it is microspotted onto a solid substrate, preferably a silanated glass substrate, to which the hydrogel microdroplet becomes covalently bound. Most preferably the hydrogel microdroplets are at least about 30 &mgr;m thick, for example about 50 &mgr;m to about 100 &mgr;m thick. The resulting biochips are particularly useful for gene discovery, gene characterization, functional gene analysis and related studies.