Analysis Common visible fluorophores have not been effective for direct fluorescence imaging of proteins and nucleic acids on membranes due to high background fluorescence from the membrane. Detection on membranes at infrared wavelengths offers the distinct advantage of very low background fluorescence.
Membranes fluoresce very little at infrared wavelengths.
Low background fluorescence results in an excellent signal to noise ratio and wide dynamic range, which allows IR labeling to be used for detection of proteins and nucleic acids on membranes. Southern blot and Western blot techniques can be used, as well as a variety of other analyses. Infrared detection is as sensitive as chemiluminescence techniques, but the direct labeling method requires no amplification steps to increase signal. Detection limits are in the low zeptomole range for DNA blots and picogram range for Western Blots. Two-color fluorescence detection not only doubles the data acquired from each scan, but also enables easy comparison of two samples.