New fluorescence correlation spectroscopy (FCS) suitable for the observation of anomalous diffusion in polymer solution: Time and space dependences of diffusion coefficients

We propose a new method of fluorescence correlation spectroscopy (FCS) enabling direct detection of anomalous diffusion as the distance dependence of diffusion coefficients (DDDC), namely, sampling-volume-controlled (SVC)-FCS. In discussing the results of SVC-FCS measurement of molecular diffusion in aqueous hyaluronan (HA) solutions in this paper, we suggest the use of “local anomalous diffusion” based on the differential of the mean-square displacement (MSD) which is convenient for understanding the total lineshapes of the observed diffusion coefficient as a function of the diffusion distance or the diffusion time.