Micro array of Ag-AgCl electrodes for cellular stimulation and sensing
Poster Sep 17, 2014
O. Pilloni*, M. A. Flores*, C. A. Santos*, A. Torres**, J. García**, H. González**, L. Oropeza-Ramos*.
Most novel efforts of miniaturizing electrophysiology techniques consist of designs based on gold and platinum microelectrodes for sensing and stimulation[1,2], which results expensive. In this study, silver–silver chloride as microelectrode material is investigated as an alternative, considering the benefits of its low cost, biocompatibility and high conductivity.
A methodology to design planar microelectrodes for sensing and stimulation of excitable cells is presented, based on the Helmholtz model to analyze the electrode-electrolyte interface impedance and the Arrhenius model to obtain the biological medium electrical properties. Two different electrode geometries are proposed to study both rounded portions and strips of tissue.
The fabrication was performed using lift-off to pattern silver traces on glass substrate, followed by electroplating to grow the silver film and finally coating the electrodes with silver chloride by soaking the traces on iron chloride. An open microfluidic PDMS layer is placed on top to contain the biological medium that keeps the tissue alive during experiments.
The platform was tested using bull frog sciatic nerve, zebra fish and bull frog heart, as samples of excitable cells, giving similar results to conventional macro electrodes. Confirming that Ag-AgCl is a feasible material for microelectrodes aim to sense and stimulate excitable cells.
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