A novel approach to imaging and visualization of minute amounts of DNA in small volume samples

This report presents a novel approach for detecting and visualizing small to trace amounts of DNA in a sample. By utilizing both the change in emission spectrum and change in fluorescence lifetime, there is a significant increase in detection sensitivity allowing for the imaging/visualizing of a picograms amount of DNA in a microliters volume. As in the previous reports, one of the oldest DNA intercalators, Ethidium Bromide (EtBr), is employed as a model system. With this new approach, it is feasible to visualize just a few hundred picograms of DNA without the need for prior DNA amplification. The sensitivity can later be largely improved by using an intercalator that exhibits a higher affinity to DNA and a larger fluorescence change upon binding to DNA (e.g., ethidium homodimer, YOYO, or Diamond nucleic acid dyes).