Detectors for single-molecule fluorescence imaging and spectroscopy

Abstract

Single-molecule observation, characterization and manipulation techniques have recently come to the forefront of several research domains spanning chemistry, biology and physics. Due to the exquisite sensitivity, specificity, and unmasking of ensemble averaging, single-molecule fluorescence imaging and spectroscopy have become, in a short period of time, important tools in cell biology, biochemistry and biophysics. These methods led to new ways of thinking about biological processes such as viral infection, receptor diffusion and oligomerization, cellular signaling, protein–protein or protein–nucleic acid interactions, and molecular machines. Such achievements require a combination of several factors to be met, among which detector sensitivity and bandwidth are crucial. Here, the necessary performance of photodetectors used in these types of experiments, the current state of the art for different categories of detectors, and actual and future developments of single-photon counting detectors for single-molecule imaging and spectroscopy, are investigated.

Acknowledgements

This work was supported by NIH Grant 5 R21 RR017474 and in part by NIH Grant 5 R01 EB000312. We are grateful to Dr Les Tack (Intevac) for information on noise figures for the NightVista E1100 camera, and to Dr Paul Hink (Burle Industries) for the loan of a fast GaAs phototube. We would like to thank the organizers of the Single Photon Workshop 2005 to have given us the opportunity to present our developments and ideas on the topic of single-photon detectors for single-molecule imaging and spectroscopy. It is our hope that common detector requirements existing across scientific fields will facilitate the emergence of new ideas and incite detector manufacturers to invest in these new market opportunities.