In microphysiological systems different signal parameters as changes in the extracellular acidification, ion concentration, and membrane potential can be easily measured with integrated microsensors. The rising interest to perform, in such microsystems, impedance measurements by means of large area interdigitated microelectrodes array, is justified by their potential use to control the cellular adhesion and for a real-time monitoring of the cell physiological state. Variations on the cell density, growth and long term cellular behaviour can be easily evaluated by monitoring the change on the electrode impedance. Recently, nanoscaled interdigitated electrode array have been also employed to detect the affinity binding of certain DNA molecules. Although the scaling of the applied electrode configuration dimensions is often compatible with modern planar sensor technologies, precise design criteria must be however introduced in order to increase the sensor and the signal processing electronic performances: the geometrical dimensions, the choice of the electrode material and the interface electrochemistry are some of the parameters to be considered when optimising new designs. In this work a simple model has been implemented in SPICE to study the effects of both the electrochemical and geometrical parameters of interdigitated microelectrode sensors (IDES) ranging over the biomedical and biotechnological application areas. Starting from previous analytical studies, based on the conformal mapping method, the core of the implemented model consists on a two-electrode conductivity cell where the double layer, the parasitic and the solution effects have been considered. With an interactive procedure the model has been extended to more electrode configurations. In order to validate the simulation results two approach have been pursued: firstly, some indications about the calculated IDES electrical parameters, as the electric potential and field distribution have been obtained with ANSYS by finite element method based simulations. Lastly, planar microelectrode test structures with different characteristics have been realised and the impedance spectroscopy measurements have been compared with the simulation results
Modelling, Design and Fabrication of Interdigitated Electrode Sensors for Biomedical Applications
Lorenzelli, Leandro;Ferrario, Lorenza;Margesin, Benno;Giacomozzi, Flavio;Guarnieri, Vittorio
2002-01-01
Abstract
In microphysiological systems different signal parameters as changes in the extracellular acidification, ion concentration, and membrane potential can be easily measured with integrated microsensors. The rising interest to perform, in such microsystems, impedance measurements by means of large area interdigitated microelectrodes array, is justified by their potential use to control the cellular adhesion and for a real-time monitoring of the cell physiological state. Variations on the cell density, growth and long term cellular behaviour can be easily evaluated by monitoring the change on the electrode impedance. Recently, nanoscaled interdigitated electrode array have been also employed to detect the affinity binding of certain DNA molecules. Although the scaling of the applied electrode configuration dimensions is often compatible with modern planar sensor technologies, precise design criteria must be however introduced in order to increase the sensor and the signal processing electronic performances: the geometrical dimensions, the choice of the electrode material and the interface electrochemistry are some of the parameters to be considered when optimising new designs. In this work a simple model has been implemented in SPICE to study the effects of both the electrochemical and geometrical parameters of interdigitated microelectrode sensors (IDES) ranging over the biomedical and biotechnological application areas. Starting from previous analytical studies, based on the conformal mapping method, the core of the implemented model consists on a two-electrode conductivity cell where the double layer, the parasitic and the solution effects have been considered. With an interactive procedure the model has been extended to more electrode configurations. In order to validate the simulation results two approach have been pursued: firstly, some indications about the calculated IDES electrical parameters, as the electric potential and field distribution have been obtained with ANSYS by finite element method based simulations. Lastly, planar microelectrode test structures with different characteristics have been realised and the impedance spectroscopy measurements have been compared with the simulation resultsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
