title: Surface plasmon enhanced diffraction for label-free biosensing.
abstract: Surface plasmon enhanced evanescent field at a (noble) metal/dielectric interface can be employed to enhance the diffraction efficiency of surface grating structure composed of biomolecules. Based on a Kretschmann configuration, we realized a diffraction biosensor to monitor the dynamic interaction of biological molecules in a label-free way. It was demonstrated by the binding of an anti-biotin antibody to the biotin-functionalized region of a periodically patterned surface, which generated significant optical contrast to diffract the surface plasmon field. With the aid of the synchronic surface plasmon resonance signal, a quadratic dependence of diffraction signal on the amount of bound antibody was found, which coincides with the theoretical expectation. Time-dependent measurements were conducted to estimate the density of biotin thiols on the functional region.
authors.affiliation: Max-Planck-Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany.
authors.forename: Fang
authors.initials: F
authors.lastname: Yu
authors.forename: Shengjun
authors.initials: S
authors.lastname: Tian
authors.forename: Danfeng
authors.initials: D
authors.lastname: Yao
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D001710:Biotin / Q000737:chemistry; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods; D013499:Surface Properties; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D000911:Antibodies, Monoclonal; D001710:Biotin