Abstract

The past decade has seen the breakthrough of ultrasensitive fluorescence analysis in the life sciences. The advent of highly efficient single photon counting avalanche photodiodes and the use of confocal fluorescent microscopes have opened the way to very high signal-to-background ratios, raising single-molecule detection to the rank of routine technique. Several methods of data processing such as Fluorescence Correlation Spectroscopy (FCS) [1] or Burst Integrated Fluorescence Lifetime (BIFL) have shown the tremendous potential of those techniques to study for instance diffusion processes in cell membranes, protein conformational changes, or ligand-target interactions. In all cases, high numerical aperture microscope objectives were needed to collect about 30% of the total emitted light (1.2 NA, water immersion).

© 2000 IEEE