title: Sensitive molecular binding assay using a photonic crystal structure in total internal reflection.
abstract: A novel optical sensor for label-free biomolecular binding assay using a one-dimensional photonic crystal in a total-internal-reflection geometry is proposed and demonstrated. The simple configuration provides a narrow optical resonance to enable sensitive measurements of molecular binding, and at the same time employs an open interface to enable real-time measurements of binding dynamics. Ultrathin aminopropyltriethoxysilane/ glutaraldehyde films adsorbed on the interface were detected by measuring the spectral shift of the photonic crystal resonance and the intensity ratio change in a differential reflectance measurement. A detection limit of 6 x 10(-5) nm for molecular layer thickness was obtained, which corresponds to a detection limit for analyte adsorption of 0.06 pg/mm(2) or a refractive index resolution of 3 x 10(-8) RIU; this represents a significant improvement relative to state-of-the-art surface-plasmon-resonance-based systems.
authors.affiliation: Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI 48109-2099, USA.
authors.forename: Yunbo
authors.initials: Y
authors.lastname: Guo
authors.forename: Charles
authors.initials: C
authors.lastname: Divin
authors.forename: Andrzej
authors.initials: A
authors.lastname: Myc
authors.forename: Fred L
authors.initials: FL
authors.lastname: Terry
authors.forename: James R
authors.initials: JR
authors.lastname: Baker
authors.forename: Theodore B
authors.initials: TB
authors.lastname: Norris
authors.forename: Jing Y
authors.initials: JY
authors.lastname: Ye
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D055095:Optics and Photonics / Q000295:instrumentation*; D010783:Photometry / Q000295:instrumentation* / Q000379:methods; D017785:Photons; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001704:Biopolymers