Medidas de Espectroscopia de Impedancia sobre membrana y membrana-receptor apoyadas, en presencia de Bisfenol A

 

Andrés Ernesto Mejía,* Chad Leidy, María T. Cortés

 

Universidad de Los Andes, Calle 25 A #4-76 apto 201, 2 432460 Colombia

 

 

Resumen

Los efectos adversos de los disruptores endocrinos (DE) sobre la salud, crean la necesidad de generar sistemas de detección de xenoestrógenos (DE). En este proyecto desarrollamos un sistema para la detección de uno de estos xenoestrógenos, el Bisfenol A (BPA), a través de la construcción de un biosensor basado en medidas de espectroscopia de impedancia para mejorar la sensibilidad. El biosensor consta de un soporte (electrodo) y una doble capa lipídica a la que le incorporamos una proteína receptor de estrógenos. Esta idea fue inicialmente concebida por V. Granek y J. Rishpon (Detecting Endocrine-Disrupting Compounds by Fast Impedance Measurements, Environ. Sci. Technol. 36 (2002) 1574-1578). Realizamos una evaluación de la bioactividad de BPA con la membrana, a través del análisis de cambios en la impedancia en función de la concentración de BPA. Los resultados encontrados indicaron que el BPA cambia la configuración de la membrana, pero en concentraciones no fisiológicas (>1ppm). Posteriormente, con la incorporación del receptor de estrógeno sobre la membrana lipídica, desarrollamos un biosensor de mayor sensibilidad haciendo posible la detección de BPA en ppb.

Palavras clave: medidas electroquímicas en rango hormonal, biosensor, espectroscopia de impedancia, Bisfenol A, membrana, receptor, xenoestrógeno, disruptores endocrinos.

 

Impedance Spectroscopy Measurements for Gotten Membrane and Membrane-Receptor, in the Presence of Bisphenol A

Abstract

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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* Corresponding author. E-mail address: andre-me@uniandes.edu.co, andreme21@gmail.com