Biofunctionalization Layer and Bacteria Cover Properties Impact on Microfabricated Planar Resonant E. Coli Bacteria Microwave Biosensor Response

This paper presents an analysis of biological layers properties covering a bacteria-selective microwave biosensor to provide an insight on phenomena driving its electrical response. A differentially-fed coupled-line section resonant sensor operating at 4.7 GHz is used as a test vehicle to establish thickness and dielectric properties of a biofunctionalization layer required to obtain selective bonding of specific bacteria to sensor`s surface. The influence on various concentrations of bacteria Escherichia coli on the frequency response of the biosensor is investigated and discussed. The frequency upshift behavior of the sensor when exposed to bacteria is explained so that sensitivity optimized geometries can be identified towards development of high-performance sensors.