Surface Plasmon Enhanced Diffraction for Label-Free Biosensing

Fang Yu, Shengjun Tian, Danfeng Yao, and Wolfgang Knoll*
Max-Planck-Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
Anal. Chem., 2004, 76 (13), pp 3530–3535
DOI: 10.1021/ac049964p
Publication Date (Web): May 19, 2004
Copyright © 2004 American Chemical Society
*

 To whom correspondence should be addressed. E-mail:  knoll@ mpip-mainz.mpg.de. Phone:  0049 (6131) 379 160. Fax:  0049 (6131) 379 360.

Abstract

Surface plasmon enhanced evanescent field at a (noble) metal/dielectric interface can be employed to enhance the diffraction efficiency of surface grating structure composed of biomolecules. Based on a Kretschmann configuration, we realized a diffraction biosensor to monitor the dynamic interaction of biological molecules in a label-free way. It was demonstrated by the binding of an anti-biotin antibody to the biotin-functionalized region of a periodically patterned surface, which generated significant optical contrast to diffract the surface plasmon field. With the aid of the synchronic surface plasmon resonance signal, a quadratic dependence of diffraction signal on the amount of bound antibody was found, which coincides with the theoretical expectation. Time-dependent measurements were conducted to estimate the density of biotin thiols on the functional region.

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History

  • Published In Issue July 01, 2004
  • Received for review January 6, 2004. Accepted March 30, 2004.

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