Development and investigation of ultrasensitive sensors based on thin films and electrical impedance (electronic tongue)

• Grant number: 12/08047-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2012
• End date: January 31, 2017
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Clarissa de Almeida Olivati
• Grantee: Priscila Alessio Constantino
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil

Abstract

The ultrasensitive and selective detection of molecules of interest is a fundamental key in the early diagnosis of sickness or dysfunctions and also in the detection of toxic substances. In this sense, the basic research on the behavior of devices is required to reach great sensitive and selective sensors. The electronic tongue via impedance spectroscopy has shown great potential for sensing applications because of its large sensitivity, specifically as regards the use of nanostructured thin films on interdigitated electrodes (IDE) forming sensing units. However, the relatively recent application of this technique in sensors highlights important questions not yet explored on their operation. It is important to note, for instance, the electronic tongue via impedance spectroscopy is not considered an analytical tool. The main objective of this project is to investigate the electronic tongue from different perspectives and thus contribute to widening their application in sensors, bringing qualitative (detection mechanisms) and quantitative (calibration curves) information. For this, the detection of analytes at different concentrations will be carried out and analyzed using, besides the usual capacitance vs. frequency curves, the Argand diagram for the preparation of calibration curves, a new approach in the area nowadays. Studies on theoretical models of equivalent electrical circuits for adjusting the data will be made. In addition, statistical and information visualization techniques will also be used to help in finding and understanding patterns of detection. The effect of adding metallic nanoparticles of different shapes in the response of these sensors will be also studied. The nanostructured films that compose the sensing units will be investigated by vibrational and electronic spectroscopes beyond microscopes. These techniques may allow us to infer about the nature of interactions at the interface film-analyte.