Electrochemical Estrogen Receptor α based Biosensor for Label-Free Detection of Estradiol

We describe a new electrochemical biosensor based on estrogen receptor (ER-) for label-free detection of 17-estradiol, a model of endocrine-disrupting compounds. ER- is coupled onto the gold electrode through its 6-His tag and NTA-copper complex. After interaction of estradiol with ER-, the biosensor presents a well-defined peak at +500mV due to estradiol oxidation (E17 peak). The linear range of detection is from 1fM to 1nM and the detection limit is 1fM. Good selectivity was obtained for interfering substances at nanomolar level, for concentration of E17 up to 0.1pM. The E17 was detected in hospital effluents.