title: Forster resonance energy transfer-based total internal reflection fluorescence reader for apoptosis.
abstract: A fluorescence reader for the detection of Forster resonance energy transfer (FRET) on surfaces of living cells is described. The method is based on multiple total internal reflections (TIR) of an incident laser beam within a glass slide, such that individual samples on top of the glass slide are illuminated simultaneously by an evanescent electromagnetic field. Enhanced cyan fluorescent protein (ECFP) anchored to the inner leaflet of the plasma membrane is optically excited and transfers its excitation energy via the peptide linker Asp-Glu-Val-Asp (DEVD) to an enhanced yellow fluorescent protein. Upon apoptosis, DEVD is cleaved, and energy transfer is disrupted, as proven by an increase of fluorescence intensity as well as of fluorescence lifetime of the donor ECFP. Due to selective excitation of membrane-associated fluorophores, intracellular fluorescence and background luminescence from the surrounding medium are eliminated. Therefore, this test system appears to be a sensitive device for the detection of apoptosis and more generally for drug screening or in vitro diagnosis on a nanometer scale.
authors.affiliation: Hochschule Aalen, Institut fur Angewandte Forschung, Beethovenstrasse 1, 73430 Aalen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bruns
authors.forename: Brigitte
authors.initials: B
authors.lastname: Angres
authors.forename: Heiko
authors.initials: H
authors.lastname: Steuer
authors.forename: Petra
authors.initials: P
authors.lastname: Weber
authors.forename: Michael
authors.initials: M
authors.lastname: Wagner
authors.forename: Herbert
authors.initials: H
authors.lastname: Schneckenburger
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D031541:Fluorescence Resonance Energy Transfer / Q000295:instrumentation* / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence / Q000295:instrumentation* / Q000379:methods; D010783:Photometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity