Characterization of Bacterial Species by Impedance Measurement
in Vitro

Abstract

In medical and food industry,most common nosocomial infections and contaminations are caused by various bacterial species such as Escherichia coli,Salmonella typhi, Pseudomonas, Bacillus etc. Identifying these bacterial contaminants early by rapid method can significantly reduce the rateof mortality and/or treatment cost.In the current study, a simple yet an innovative method was adopted to characterize and identify the bacterial species through impedance measurement. Briefly, an impedance measuring circuit was designed, simulated and fabricated to measure live cell impedance. The Impedance Analyzer was used to generate Impedance profile of individual bacterial species. The impedance measuring circuit with buffer ICs was implemented by using breadboard and was verified using digital storage oscilloscope (DSO)as an output device and function generator as an input with a power supply of 12V.A Lab VIEW program was designed to simulate the impedance measuring circuit using a Data Acquisition (DAQ) module and the results were verified. It was observed that impedance decreased with an increase in frequency of input signal. Exponential curves were observed while plotting impedance at different concentrations of each bacterial species against the log of input signal frequencies. With increase in distance between the measuring electrodes, impedance increased. Various bacterial species can be differentiated by the virtue of their impedance spectrum obtained at different frequencies that can further be used in various medical, industrial and domestic set ups to identify various microorganism.Therefore, the above technology shall be useful as a low-cost device for food safety, medical microbial screening and public health programs in most of the developing countries.