Monte Carlo Simulation of a Single-molecule Detection Experiment

The physical and instrumental processes that occur in experiments for the detection of individual fluorescent molecules in solution are described, with emphasis on their incorporation into a quantitative Monte Carlo simulation. The simulation is applied to the conditions of a past experiment [Appl. Opt. 34, 3208 (1995)], which utilizes a sheath flow system for high detection efficiency, and it generates comparable results, while helping to identify experimental limitations. The simulation indicates that the use of low dead-time electronics and appropriate selection of experimental parameters should enable detection at more rapid rates for applications in which large numbers of molecules are to be efficiently counted.