title: Electrochemical immunosensor for rapid and sensitive determination of estradiol.
abstract: This work describes the preparation of an electrochemical immunosensor for estradiol based on the surface modification of a screen printed carbon electrode with grafted p-aminobenzoic acid followed by covalent binding of streptavidin (Strept) and immobilization of biotinylated anti-estradiol (anti-estradiol-Biotin). The hormone determination was performed by applying a competitive immunoassay with peroxidase-labelled estradiol (HRP-estradiol) and measurement of the amperometric response at -200 mV using hydroquinone (HQ) as redox mediator. The calibration curve for estradiol exhibited a linear range between 1 and 250 pg mL(-1) (r=0.990) and a detection limit of 0.77 pg mL(-1) was achieved. Cross-reactivity studies with other hormones related with estradiol at physiological concentration levels revealed the practical specificity of the developed method for estradiol. A good reproducibility, with RSD=5.9% (n=8) was also observed. The operating stability of a single bioelectrode modified with anti-estradiol-Biotin-Strept was nine days when it was stored at 8°C under humid conditions between measurements. The developed immunosensor was applied to the analysis of certified serum and spiked urine samples with good results.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University Complutense of Madrid, 28040 Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Ojeda
authors.forename: J
authors.initials: J
authors.lastname: López-Montero
authors.forename: M
authors.initials: M
authors.lastname: Moreno-Guzmán
authors.forename: B C
authors.initials: BC
authors.lastname: Janegitz
authors.forename: A
authors.initials: A
authors.lastname: González-Cortés
authors.forename: P
authors.initials: P
authors.lastname: Yáñez-Sedeño
authors.forename: J M
authors.initials: JM
authors.lastname: Pingarrón
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004958:Estradiol / Q000097:blood* / Q000737:chemistry / Q000652:urine*; D005260:Female; D006801:Humans; D057230:Limit of Detection; D015394:Molecular Structure; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D004958:Estradiol