DIODE-LASER BASED DETECTION OF SINGLE MOLECULES IN SOLUTIONS

Using a confocal microscope we studied bursts of fluorescence photons from single dye molecules that were excited at 632 nm with a CW diode laser or helium neon laser. The measurements were performed with new r hodamine derivatives,in ethylene glycol solution. The potential of thi s method for future construction of a low-cost instrument for single-m olecule detection is pointed out. To demonstrate the utility of our ne w dyes in bioanalytical applications we showed the single-molecule det ection of labeled oligonucleotides in water.