SPECTROSCOPY, IMAGING, OTHER TECHNIQUES |
Fluorescence Correlation Spectroscopy of Finite-Size Particles
Bin Wu 1*, Yan Chen 1 and Joachim D. Müller 1
1 University of Minnesota
* To whom correspondence should be addressed. E-mail: binwu{at}physics.umn.edu.
Submitted on May 15, 2007
Revised on June 25, 2007
Accepted on 26 November 2007
 |
Abstract |
|---|
A formulism is presented to study fluorescence correlation spectroscopy for particles with size comparable to the beam waist of the observation volume. Analytical correlation curves are derived for some experimentally interesting particle geometries. It is found that the finiteness of the particle generally decreases the value of the correlation amplitude and increases the correlation time compared to a point particle model. Furthermore, not only the size but also the distribution of fluorophores affects the shape of the correlation function. This is experimentally demonstrated with surface and internally labeled fluorescent spheres. In addition, experiments are performed on fluorescent spheres of different radii to validate the model by comparing the results to theoretical predictions.
Key Words:
Fluorescence Fluctuation Spectroscopy, Nanoparticle and Microparticle, Photon Statistics, Two-photon spectroscopy
