Electrochemical biosensor for estrogenic substance using lipid bilayers modified by Au nanoparticles

There is a growing demand for new technologies that are capable of screening the wide variety of xenoestrogens in environment. Here, a nanostructure electrochemical biosensor was developed to directly detect and screen estrogenic substances based on estrogen receptor (ER) binding without the use of radio- or enzyme-labeled compounds. The biosensor was fabricated by immobilization of ERs in supported bilayer lipid membrane (s-BLM) modified with Au nanoparticles, and the properties of the modified electrodes were characterized by cyclic voltammetry and impedance spectroscopy. The results indicated that the biosensor was able to detect the natural estrogen 17β-estradiol with an acceptable linear correlation ranging from 5 to 150 ng/L and a detection limit of 1 ng/L. The biosensor could also detect other known xenoestrogens such as bisphenol A and 4-nonylphenol with satisfied sensitivity and quantitative results. The biosensor showed good reliability and repeatability, and the Au nanoparticles greatly enhanced the sensitivity and stability of the biosensor. Moreover, estrogenic activity of water samples determined by this biosensor was in good agreement with that determined by MCF-7 cell proliferation assay.