Sensors 2014, 14(12), 23307-23320; https://doi.org/10.3390/s141223307
Real-Time, Label-Free Detection of Biomolecular Interactions in Sandwich Assays by the Oblique-Incidence Reflectivity Difference Technique
Yung-Shin Sun 1,*
and Xiangdong Zhu 2
and Xiangdong Zhu 21
Department of Physics, Fu-Jen Catholic University, New Taipei City 24205, Taiwan
2
Department of Physics, University of California at Davis, Davis, CA 95616, USA
*
Author to whom correspondence should be addressed.
Received: 21 October 2014 / Revised: 20 November 2014 / Accepted: 25 November 2014 / Published: 5 December 2014
(This article belongs to the Special Issue Advances in Optical Biosensors)
Abstract
One of the most important goals in proteomics is to detect the real-time kinetics of diverse biomolecular interactions. Fluorescence, which requires extrinsic tags, is a commonly and widely used method because of its high convenience and sensitivity. However, in order to maintain the conformational and functional integrality of biomolecules, label-free detection methods are highly under demand. We have developed the oblique-incidence reflectivity difference (OI-RD) technique for label-free, kinetic measurements of protein-biomolecule interactions. Incorporating the total internal refection geometry into the OI-RD technique, we are able to detect as low as 0.1% of a protein monolayer, and this sensitivity is comparable with other label-free techniques such as surface plasmon resonance (SPR). The unique advantage of OI-RD over SPR is no need for dielectric layers. Moreover, using a photodiode array as the detector enables multi-channel detection and also eliminates the over-time signal drift. In this paper, we demonstrate the applicability and feasibility of the OI-RD technique by measuring the kinetics of protein-protein and protein-small molecule interactions in sandwich assays. View Full-TextKeywords:
label-free biosensor; oblique-incidence reflectivity difference (OI-RD); protein-protein interaction; protein-small molecule interaction; real-time kinetics
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MDPI and ACS Style
Sun, Y.-S.; Zhu, X. Real-Time, Label-Free Detection of Biomolecular Interactions in Sandwich Assays by the Oblique-Incidence Reflectivity Difference Technique. Sensors 2014, 14, 23307-23320.