Sensitive molecular binding assay using a photonic crystal structure in total internal reflection

Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, MI 48109-2099, USA.
Optics Express (Impact Factor: 3.53). 09/2008; 16(16):11741-9. DOI: 10.1364/OE.16.011741
Source: PubMed

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.

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Available from: James R Baker, Dec 17, 2013
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