title: Folded cavity SOI microring sensors for high sensitivity and real time measurement of biomolecular binding.
abstract: We demonstrate folded waveguide ring resonators for biomolecular sensing. We show that extending the ring cavity length increases the resonator quality factor, and thereby enhances the sensor resolution and minimum level of detection, while at the same time relaxing the tolerance on the coupling conditions to provide stable and large resonance contrast. The folded spiral path geometry allows a 1.2 mm long ring waveguide to be enclosed in a 150 microm diameter sensor area. The spiral cavity resonator is used to monitor the streptavidin protein binding with a detection limit of approximately 3 pg/mm(2), or a total mass of approximately 5 fg. The real time measurements are used to analyze the kinetics of biotin-streptavidin binding.
authors.affiliation: Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, Ontario, Canada. Danxia.Xu@nrc-cnrc.gc.ca
authors.forename: D X
authors.initials: DX
authors.lastname: Xu
authors.forename: A
authors.initials: A
authors.lastname: Densmore
authors.forename: A
authors.initials: A
authors.lastname: Delâge
authors.forename: P
authors.initials: P
authors.lastname: Waldron
authors.forename: R
authors.initials: R
authors.lastname: McKinnon
authors.forename: S
authors.initials: S
authors.lastname: Janz
authors.forename: J
authors.initials: J
authors.lastname: Lapointe
authors.forename: G
authors.initials: G
authors.lastname: Lopinski
authors.forename: T
authors.initials: T
authors.lastname: Mischki
authors.forename: E
authors.initials: E
authors.lastname: Post
authors.forename: P
authors.initials: P
authors.lastname: Cheben
authors.forename: J H
authors.initials: JH
authors.lastname: Schmid
mesh_terms: D001665:Binding Sites; D015374:Biosensing Techniques / Q000295:instrumentation*; D008904:Miniaturization; D055095:Optics and Photonics / Q000295:instrumentation*; D010783:Photometry / Q000295:instrumentation*; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000295:instrumentation*; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins