title: Total internal reflection fluorescence correlation spectroscopy (TIR-FCS) with low background and high count-rate per molecule.
abstract: We designed a fluorescence correlation spectroscopy (FCS) system for measurements on surfaces. The system consists of an objective-type total internal reflection fluorescence (TIRF) microscopy setup, adapted to measure FCS. Here, the fluorescence exciting evanescent wave is generated by epi-illumination through the periphery of a high NA oil-immersion objective. The main advantages with respect to conventional FCS systems are an improvement in terms of counts per molecule (cpm) and a high signal to background ratio. This is demonstrated by investigating diffusion as well as binding and release of single molecules on a glass surface. Furthermore, the size and shape of the molecule detection efficiency (MDE) function was calculated, using a wave-vectorial approach and taking into account the influence of the dielectric interface on the emission properties of fluorophores.
authors.forename: Kai
authors.initials: K
authors.lastname: Hassler
authors.forename: Marcel
authors.initials: M
authors.lastname: Leutenegger
authors.forename: Per
authors.initials: P
authors.lastname: Rigler
authors.forename: Ramachandra
authors.initials: R
authors.lastname: Rao
authors.forename: Rudolf
authors.initials: R
authors.lastname: Rigler
authors.forename: Michael
authors.initials: M
authors.lastname: Gösch
authors.forename: Theo
authors.initials: T
authors.lastname: Lasser