Analysis of the sensitivity of an impediometric biosensor for the detection of bacteria

An electrostatic finite element model of an interdigitated microelectrode array impedance biosensor has been used to further investigate the biosensor´s sensitivity to detecting bacteria. Specifically, the sensor´s sensitivity towards bacteria of different sizes was investigated and it was found that the biosensor was more sensitive to certain bacteria depending on their diameter. Further, it was discovered that by altering the sensor´s physical wavelength, the sensor´s topology can be optimized for the detection of a specific bacteria based on bacteria diameter. The effect of bacteria aggregation was also investigated. Increased aggregation i.e. increased numbers of bacteria on the sensor surface, eventually leads to sensor saturation and a maximum change in normalized capacitance can be estimated for a specific sensor topology. It is hoped that the modelling work presented here will aid in improved and knowledgeable development of the actual sensor for the rapid detection of bacteria.