SYNTHESIS, CHROMATOGRAPHIC-SEPARATION, AND CHARACTERIZATION OF NEAR-INFRARED-LABELED DNA OLIGOMERS FOR USE IN DNA-SEQUENCING

Traditionally, visible fluorophores have been used as labels in DNA sequencing. They absorb and fluoresce in a region of the spectrum that is susceptible to biological interferences in sequencing samples. The increased noise level due to autofluorescence of glass, solvent, or impurities can greatly reduce the potential sensitivity of the analysis. In an attempt to increase the sensitivity, we have investigated the use of near-infrared (near-IR) fluorophores as labels in DNA sequencing. Near-IR fluorophores possess spectral properties which are observed between 700 and 1200 nm, a region with characteristically little interference by biomolecules. Therefore, the detection of near-IR dyes is not limited by noise levels, but rather detector capabilities. Near-IR dyes are also suitable for selective excitation with commercially available laser diodes which can further enhance the observed fluorescence signal. We have covalently linked functionalized near-IR dyes to modified DNA oligomers for use in DNA sequencing. We report the synthesis and chromatographic purification of near-IR-labeled DNA oligomers. We further discuss the inherent properties of the conjugates and their use in DNA sequencing procedures.