Electrochemical Immunoassay Strategies for Detection of Bovine Serum Albumin-17beta-Estradiol

The endocrine-disrupting compound 17beta-estradiol (E2) is endogenously produced by all mammalian species. Over the last years, many studies have suggested that E2 are growing concern that even at low concentrations may adversely affect fish, wildlife, ecosystems and possibly human health.

We propose strategies for detection of Bovine serum albumin-17beta-estradiol (BSA-E2) by using CdSe Quantum Dots as electrochemical labels for amplifying signal. BSA-E2 was chosen as a model 17beta-estradiol in this work.

In this model the CdSe QDs were used as labels for amplifying electrochemical signal and were conjugation with secondary anti-17beta-estradiol antibody (anti-E2 antibody) in heterogeneous sandwich immunoassay. Using two-step protocol for conjugation of CdSe QDs and anti-E2 antibody because of antibody contains both carboxylates and amines ^[1]. In the first step, EDC is used in the presence of sulfer-NHS to activate carboxylates on the CdSe QDs to intermediates sulfer-NHS esters. The second step is activates CdSe QDs by add the anti-E2 antibody solution to be coupled.

Furthermore, Anodic stripping voltammetry (ASV) is a powerful method for the determination of trace heavy metals, based on relatively inexpensive and portable equipment, and its analysis time is much shorter than other methods. Here the Cd²⁺form acid dissolution step was detected. For this purposed the anti BSA antibody was immobilization Nafion/ITO electrode. The modification surface and subsequently stepwise immobilization was investigated by EIS and AFM.

References

[1] G.T. Hermanson,Bioconjugate Techniques(second ed.)Elsevier, London (2008)

Acknowledgment

National Natural Science Foundation of China (No. 41073060, No. 21377023) Research Fund for the Doctoral Program of Higher Education of China (No. 20100075110010 )