title: Interferometric biosensor based on planar optical waveguide sensor chips for label-free detection of surface bound bioreactions.
abstract: A label free optical biosensor based on a free-space Young interferometer configuration is presented. Commercial planar Ta(2) O(5) waveguides are used as sensing elements and allow the investigation of surface bound bioreactions like immunoreactions or biological affinity systems. Design criteria are discussed and a detailed characterization of the sensor performance is presented. The developed interferometer yields an effective refractive index resolution of 9 x 10(-9), corresponding to a surface coverage of approximately 13 fg/mm(2). The performance of the system is characterized by two different affinity systems: the antibody-antigen complex protein G-immunoglobulin G is used as a model system for monitoring reaction kinetics. Further measurements on a silanized surface show the formation of a streptavidin monolayer on a biotinylated surface.
authors.affiliation: Fraunhofer Institute for Physical Measurement Techniques IPM, Freiburg, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Schmitt
authors.forename: Bernd
authors.initials: B
authors.lastname: Schirmer
authors.forename: Christian
authors.initials: C
authors.lastname: Hoffmann
authors.forename: Albrecht
authors.initials: A
authors.lastname: Brandenburg
authors.forename: Patrick
authors.initials: P
authors.lastname: Meyrueis
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007368:Interferometry / Q000295:instrumentation* / Q000379:methods; D055095:Optics and Photonics / Q000295:instrumentation*; D013194:Staining and Labeling; D014159:Transducers
chemical_list: D007074:Immunoglobulin G