Fig. 3.

Estimating the number of molecules in the detection volume. The numbers of molecules in the DV were obtained from the inverse of the autocorrelation function, such as shown in the inset, extrapolated to a lag time 0. Average diffusion coefficient of SeTau and its correlation time were 250 μm²/s and 10.5 ms, respectively. Inset autocorrelation function of 10 nM SeTau solution giving 6 molecules. The laser power (before objective) = 0.1 μW