Detection of Quadruplex DNA by Luminescence Enhancement of Lanthanide Ions and Energy Transfer from Lanthanide Chelates

Small amounts of quadruplex DNA have been detected using luminescence enhancement of aqueous lanthanide ions and energy transfer from lanthanide chelates. The 22mer human telomeric DNA, AGGG(TTAGGG)(3), was detected using europium ions at concentrations as low as 20 ppb DNA. Detection with terbium ions was not possible due to the inherent weak luminescence intensities of lanthanides. Two different terbium chelates were used to overcome this challenge. When quadruplex DNA was added to the chelates there was a change in the excited-state lifetime of the chelate with subsequent energy transfer to the DNA. Experiments showed an increase in the amount of energy transferred from the chelate to the human telomeric DNA and other quadruplex sequences increased as a function of DNA concentration.