Impedance Spectroscopic Analysis of the Interidigitated Flexible Sensor for Bacteria Detection

Abstract

In this paper we presented economical interdigitated flexible sensor on the paper substrate for bacteria detection. The impedance measurement was performed in the frequency range of 12.6 kHz–100 kHz for the suspensions with cell density of 1.5·108 CFU/mL, 1.5·105 CFU/mL and 1.5·102 CFU/mL of Pseu- domonas aeruginosa and Staphylococcus aureus bacteria cells, as well as for a sterile saline. Using the measured impedance data, we observed that sensor impedance magnitude increases when bacteria concentration increases. Moreover, impedance spectro- scopic analysis was carried out to identify an equivalent electrical circuit for the sensor modelling. Through statistical analysis it was found that all model parameters changes according to the bacteria concentration. Additionally, obtained results showed that all fittings results in root mean square error lower than 0.076 Ω for impedance magnitude, and 0.054◦ for impedance phase angle. Moreover, maximum relative errors for impedance magnitude and phase angle were 0.329% and 2.898%, respectively