title: Interpretation of fluorescence correlation spectra of biopolymer solutions.
abstract: Fluorescence correlation spectroscopy (FCS) is regularly used to study diffusion in non-dilute "crowded" biopolymer solutions, including the interior of living cells. For fluorophores in dilute solution, the relationship between the FCS spectrum G(t) and the diffusion coefficient D is well-established. However, the dilute-solution relationship between G(t) and D has sometimes been used to interpret FCS spectra of fluorophores in non-dilute solutions. Unfortunately, the relationship used to interpret FCS spectra in dilute solutions relies on an assumption that is not always correct in non-dilute solutions. This paper obtains the correct form for interpreting FCS spectra of non-dilute solutions, writing G(t) in terms of the statistical properties of the fluorophore motions. Approaches for applying this form are discussed.
authors.affiliation: Department of Physics, Worcester Polytechnic Institute, Worcester, MA, 01609.
authors.forename: George D J
authors.initials: GD
authors.lastname: Phillies
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D008962:Models, Theoretical; D012996:Solutions; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D001704:Biopolymers; D012996:Solutions
keywords: crowded solutions; diffusion; fluorescence correlation spectroscopy; spectral interpretation