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A surface plasmon resonance based inhibition immunoassay for sensitive and selective detection of 17β-estradiol.pdf (16.54 MB)

A Surface Plasmon Resonance Based Inhibition Immunoassay for Sensitive and Selective Detection of 17β-Estradiol

preprint
submitted on 02.03.2018, 18:47 and posted on 05.03.2018, 16:18 by Yong Cao, Mark T. McDermott

Quantitative measurement of small-molecule metabolites is now emerging as an effective way to link the metabolite profile to disease state. Surface plasmon resonance (SPR) is a sensing platform that has demonstrated applicability for a large range of biomolecules. However, direct detection of small molecules with SPR challenges the refractive index based detection mechanism. Herein, we utilized an indirect detection format and developed an inhibition immunoassay for the quantitative measurement of 17β-estradiol (E2) using SPR. One competitor, BSA-E2 conjugate, was immobilized to the SPR chip via the reaction between the primary amino group of the conjugate and the succinimide group (NHS) introduced by the formation of a thiol-NHS monolayer on gold surface. Free E2 molecules compete with BSA-E2 on chip surface for binding sites provided by a monoclonal anti-E2 antibody. It was found the binding affinity of the antibody to BSA-E2 conjugate increases with decreasing surface coverage of BSA-E2 conjugate. Under optimal conditions, a sigmoidal calibration curve with a negative slope and a dynamic range from 10 pM to 2 nM was generated. The detection limit of the immunoassay is estimated to be 0.3 pM. Moreover, the immunoassay exhibits high specificity for E2 detection using estrone (E1) as a potential interference.

History

Email Address of Submitting Author

yong2@ualberta.ca

Email Address(es) for Other Author(s)

mark.mcdermott@ualberta.ca

Institution

University of Alberta

Country

Canada

ORCID For Submitting Author

0000-0001-5354-9628

Declaration of Conflict of Interest

No conflict of interest

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