Multipurpose high sensitivity luminescence analyzer (LUANA): use in gel electrophoresis

Many applications in molecular biology require the rapid and high-sensitivity detection of biological macromolecules. Here we describe a luminescence analyzer (LUANA), featuring xenon lamp-based illumination and a cooled CCD camera as detector. Luminescent samples (gels, membranes or microplates) are placed in a light-tight chamber, and computer software is used to control the camera and to display and analyze the images. LUANA can be used with a broad spectrum of excitation and emission wavelengths (200-1000 nm), allowing a choice of many fluorescent dyes and facilitating multicolor imaging. We show that LUANA is readily applicable to gel electrophoresis and highly sensitive; on gels we could detect < 100 fg of Cy5TM-labeled protein and 0.1 ng of plasmid DNA labeled with a fluorescent intercalator. We observed a linear response for sample concentrations differing by two orders of magnitude using a single acquisition time. This range could be further extended by using different acquisition times. We have also used LUANA in two-color imaging of DNA and for screening of antigen-antibody and peptide-protein complexes by gel bandshift.