Patent ID: 6936472

Claim:
An improved method for repeatedly applying solutions of reactive nucleotide monomers to a particular feature on a chemically-prepared surface of a solid substrate of a molecular array in order to synthesize a substrate-bound oligonucleotide polymer within the feature having a predetermined monomer sequence, the method comprising: applying an initial volume of an initial solution of a reactive nucleotide monomer to the feature to react with reactive substrate-bound groups of the feature to produce a nascent substrate-bound oligonucleotide polymer within a region of the surface of the solid substrate in contact with the initial volume of solution; and repeatedly: applying a solution containing an activating agent to the feature in order to activate nascent oligonucleotide polymers within the feature for reaction with a subsequently applied reactive nucleotide monomer; and applying an additional covering volume of a solution of a reactive nucleotide monomer to the feature in order to chemically bind the reactive nucleotide monomer to the nascent polymers within the feature.