Disposable amperometric immunosensor for the detection of 17-β estradiol using screen-printed electrodes

An amperometric immunosensor for rapid determination of 17-β estradiol (17-β-E2) was developed. The immunosensor was based on disposable screen-printed carbon electrodes. Both monoclonal and polyclonal antibodies were assessed and the use of monoclonal antibodies resulted in a more sensitive assay. Detection was facilitated by labelling the antibody with alkaline phosphatase and amperometric measurements were performed at +300 mV versus Ag/AgCl using p-aminophenyl phosphate (p-APP) as substrate. The sensor could detect 17-β-estradiol in an environmentally relevant range with a detection limit of 0.25 pg/ml (EC50: 61.6 pg/ml). Cross-reactivity studies were carried out to ascertain the specificity of the assay. The precision was evaluated and all CV were less than 11%. Finally, the suitability of the sensor for detection of 17-β-E2 in various water samples was assessed.