Abstract

Fluorescence correlation microscopy (FCM) is based on intensity fluorescence fluctuations occurring in very small sample volumes containing few molecules From the analysis of the fluorescence signal autocorrelation, parameters such as molecular concentration, diffusion constant and photophysical properties can be investigated. A method to define a very small volume is based on two-photon excitation (TPE) which inherently confines the excitation volume to the focus region. Eventual photodamage is also restricted to this small volume, and the use of an excitation wavelength in the IR allows a best penetration depth in biological samples.

© 2000 IEEE