Abstract

MEJIA, Andrés Ernesto; LEIDY, Chad  and  CORTES, María T.. Impedance Spectroscopy Measurements for Gotten Membrane and Membrane-Receptor, in the Presence of Bisphenol A. Port. Electrochim. Acta [online]. 2009, vol.27, n.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.

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

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