Indirect Inhibitive Immunoassay for Estradiol Using Surface Plasmon Resonance Coupled to Online In-Tube SPME

Abstract

A new immunoassay method using surface plasmon resonance (SPR) coupled with online, in-tube, solid-phase microextraction (SPME) was developed and applied to detect estradiol in human serum and seawater using an indirect inhibitive immunoassay format. The binding of antibody was inhibited by estradiol in a dose-dependent manner, and the calibration curve was generated by linear fit over the range of 0.3125–20.0 ng/ml, with a correlation coefficient of R² = 0.99996. The detection limit (S/N = 3) was 0.17 ng/ml. This study demonstrates, for the first time, the feasibility of in-tube SPME-SPR to determine estradiol in human serum and seawater.

Keywords:

• Biosensor
• estradiol
• immunoassay
• in-tube solid-phase microextraction
• surface plasmon resonance

This work was financially supported by the National High Technology Research and Development Program of China (2006AA06Z406), the National Natural Science Foundation of China (Grants 30727001, 60736037, 50873114, and 50830106), and the 973 Program of Ministry of Science and Technology of the People's Republic of China (MOST) (2006CB302905). The authors thank Professor Zhenquan Guo (Life Sciences Center of Peking University, Beijing) for providing the antiestradiol monoclonal antibody and Ms. Weiwei Zhang (National Marine Environmental Monitoring Center of China) for help in obtaining the contaminated and standard seawater samples.

Notes

Note. N/A: not applicable.