Toward photostable multiplex analyte detection on a single mode planar optical waveguide

Harshini Mukundan, Hongzhi Xie, Aaron Anderson, W. Kevin Grace, Jennifer S. Martinez, Basil Swanson

Research output: Contribution to journalConference articlepeer-review

5 Scopus citations

Abstract

We have developed a waveguide-based optical biosensor for the sensitive and specific detection of biomarkers associated with disease. Our technology combines the superior optical properties of single-mode planar waveguides, the robust nature of functionalized self-assembled monolayer sensing films and the specificity of fluorescence sandwich immunoassays to detect biomarkers in complex biological samples such as serum, urine and sputum. We have previously reported the adaptation of our technology to the detection of biomarkers associated with breast cancer and anthrax. However, these approaches primarily used phospholipid bilayers as the functional film and organic dyes (ex: AlexaFluors) as the fluorescence reporter. Organic dyes are easily photodegraded and are not amenable to multiplexing because of their narrow Stokes' shift. Here we have developed strategies for conjugation of the detector antibodies with quantum dots for use in a multiplex detection platform. We have previously evaluated dihydroxylipoic acid quantum dots for the detection of a breast cancer biomarker. In this manuscript, we investigate the detection of the Bacillus anthracis protective antigen using antibodies conjugated with polymer-coated quantum dots. Kinetics of binding on the waveguide-based biosensor is reported. We compare the sensitivity of quantum dot labeled antibodies to those labeled with AlexaFluor and demonstrate the photostability of the former in our assay platform. In addition, we compare sulfydryl labeling of the antibody in the hinge region to that of nonspecific amine labeling. This is but the first step in developing a multiplex assay for such biomarkers on our waveguide platform.

Original languageEnglish (US)
Article number71670A
JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7167
DOIs
StatePublished - 2009
Externally publishedYes
EventFrontiers in Pathogen Detection: From Nanosensors to Systems - San Jose, CA, United States
Duration: Jan 24 2009Jan 26 2009

Keywords

  • Anthrax
  • Biosensor
  • Multiplex
  • Quantum dots
  • Waveguides

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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