MEJIA, Andrés Ernesto; LEIDY, Chad    CORTES, María T.. Impedance Spectroscopy Measurements for Gotten Membrane and Membrane-Receptor, in the Presence of Bisphenol A. []. , 27, 3, pp.289-298. ISSN 0872-1904.

The adverse effects of endocrine disrup tors on human health have created a need for screening systems to detect xenoestrogens. In this project, we develop a system to detect one of these xenestrogens, Bisphenol A (BPA), through the development of a biosensor based on impedance measurements. The biosensor consists of a supported lipid bilayer that incorporates a protein receptor sensitive to the presence of BPA. This setup was originally proposed by V. Granek and J. Rishpon [19]; we now present an alternative method of analysis to increase sensibility. As a preliminary evaluation of bioactivity of BPA we measured the direct interaction of this xenoestrogen with the membrane by analyzing changes in the membrane impedance as a function of BPA concentration. The results indicate that BPA inserts and disrupts the membrane, but only at very high unphysiological BPA concentrations (> 1 ppm). We then developed a high sensitivity biosensor, based on the detection of the electric signal by means of impedance spectroscopy, resulting from the interaction between BPA and an estrogen receptor reconstituted in a lipid membrane. The results show that the presence of the receptor increases by several orders of magnitude the sensitivity of the system, making it possible to detect BPA at ppb.

: electrochemical measures in hormonal range; biosensor; impedance spectroscopy; Bisphenol A; membrane; receptor; xenoestrogen; endocrine disruptors.

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