Separation Solid-phase hybridization, in which nucleic acid stands tethered to a support bind DNA molecules from solution, underpins the modern microarray and biosensor biotechnologies now widely used for genotyping, studying gene expression and for biological detection. The molecular processes, namely sequence-specific recognition between comprementary probe and target molecules, is fairly well understood in bulk solution. We study the hybridization kinetics of surface attached DNA oligomers and present calculations based on polyelectrolyte brush theory. Then, we show a model of DNA hybridization in bulk solution.