Fundamental Studies of DNA Adsorption and Hybridization on Solid Surfaces

Arrays of DNA or oligonucleotide sequences immobilized on a solid surface are becoming important tools for identifying genetic defects, pathogens, forensic samples, gene expression profiles, etc. by hybridization to solution-phase complements. However little fundamental work has been done on such areas as solution and surface diffusion, steric hindrance due to the solid support, immobilized probe density spacer arm effects, and other parameters which can affect hybridization. Our current results include data on adsorption equilibria and desorption rates of oligonucleotide on various types of silanized surfaces, surface diffusion constants, and preliminary data on spacers and the effect of sequences on either side of the hybridization region. Surface concentrations which cause fluorescence quenching are surprisingly easy to attain, indicating close packing and revealing a potential problem which may exist in certain situations.