Theory of fluorescence correlation spectroscopy at variable observation area for two-dimensional diffusion on a meshgrid

TL;DR

This paper develops a comprehensive theoretical framework for fluorescence correlation spectroscopy with variable observation areas, enabling the detection and quantification of meshgrid barriers affecting two-dimensional diffusion in membranes.

Contribution

It provides a complete theory that confirms numerical findings and allows quantitative analysis of experimental data to determine sub-wavelength mesh sizes.

Findings

Theory confirms meshgrid effects on diffusion.

Allows extraction of sub-wavelength mesh size from data.

Discusses optimal time scales for experiments.

Abstract

It has recently been proposed, with the help of numerical investigations, that fluorescence correlation spectroscopy at variable observation area can reveal the existence of a meshgrid of semi-permeable barriers hindering the two-dimensional diffusion of tagged particles, such as plasmic membrane constituents. We present a complete theory confirming and accounting for these findings. It enables a reliable, quantitative exploitation of experimental data from which the sub-wavelength mesh size can be extracted. Time scales at which fluorescence correlation spectroscopy must be performed experimentally are discussed in detail.