title: Grazing-incidence neutron-induced fluorescence probes density profiles of labeled molecules at solid/liquid interfaces.
abstract: We report on the use of characteristic prompt γ-fluorescence after neutron capture induced by an evanescent neutron wave to probe densities and depth profiles of labeled molecules at solid/liquid interfaces. In contrast to classical scattering techniques and X-ray fluorescence, this method of "grazing-incidence neutron-induced fluorescence" combines direct chemical specificity, provided by the label, with sensitivity to the interface, inherent to the evanescent wave. We demonstrate that the formation of a supported lipid membrane can be quantitatively monitored from the characteristic fluorescence of (157)Gd(3+) ions bound to the headgroup of chelator lipids. Moreover, we were able to localize the (157)Gd(3+) ions along the surface normal with nanometer precision. This first proof of principle with a well-defined model system suggests that the method has a great potential for biology and soft matter studies where spatial resolution and chemical sensitivity are required.
authors: Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, Heidelberg, Germany. schnecke@ill.fr
authors: Emanuel
authors: E
authors: Schneck
authors: Michael
authors: M
authors: Jentschel
authors: Christian
authors: C
authors: Gege
authors: Motomu
authors: M
authors: Tanaka
authors: Bruno
authors: B
authors: Demé
mesh_terms: D005456:Fluorescent Dyes / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D008954:Models, Biological; D009502:Neutrons; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013194:Staining and Labeling / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D008563:Membrane Lipids; D005682:Gadolinium