Development of a screen-printed carbon electrochemical immunosensor for picomolar concentrations of estradiol in human serum extracts

Hart, J. P.; Pemberton, Roy; Mottram, T. T.

Abstract

Investigations into the development of a prototype electrochemical immunosensor for estradiol (E2) are described. After optimising reagent loadings in a 96-well enzyme-linked immunosorbent assay (ELISA), antibodies (rabbit anti-mouse IgG and monoclonal mouse anti-E2) were immobilised by passive adsorption onto the surface of screen-printed carbon electrodes (SPCEs). A competitive immunoassay was then performed using an alkaline-phosphatase (ALP)-labelled E2 conjugate. Calibration plots for E2 buffer standards, performed colorimetrically on the SPCEs using a para-nitrophenyl phosphate substrate solution, were in good agreement with ELISA calibration plots. Electrochemical measurements were then performed using differential pulse voltammetry (DPV) following the production of 1-naphthol from 1-naphthyl phosphate. The calibration plot of DPV peak current versus E2 concentration showed a measurable range of 25-500 pg/ml with a detection limit of 50 pg/ml. A coefficient of variation of between 13.0 and 15.6% was obtained for repeat measurements. The immunosensor was applied to the determination of E2 in spiked serum, following an extraction step with diethyl ether. A mean recovery for the method of 102.5% was obtained with a CV of 19.1%. The options available for further development of the sensor regarding precision, limit of detection and direct sample analysis are discussed. © 2005 Elsevier B.V. All rights reserved.

• Journal Article Type: Article
• Publication Date: Jun 30, 2005
• Journal: Journal of Biochemical and Biophysical Methods
• Print ISSN: 0165-022X
• Publisher: Elsevier
• Peer Reviewed: Not Peer Reviewed
• Volume: 63
• Issue: 3
• Pages: 201-212
• DOI: https://doi.org/10.1016/j.jbbm.2005.05.002
• Keywords: estradiol, screen-printed carbon electrode, immunosensor, ; differential pulse voltammetry
• Public URL: https://uwe-repository.worktribe.com/output/1049052
• Publisher URL: http://dx.doi.org/10.1016/j.jbbm.2005.05.002