Design of a Biosensor Based on Interdigitated Microelectrodes with Detection Zone Controlled by an Integrated Microfluidic Channel

The design and simulation of a biosensor based on interdigitated microelectrodes for bacteria detection is presented. The biosensor includes a microchannel to ensure the flow of the sample through the space between microelectrodes, where the surface is biofunctionalized with antibodies to capture the bacteria. The design was built on COMSOL Multiphysics® software. The effects of the microelectrode thickness and the channel depth on the biosensor sensitivity were studied by simulation. There is a specific microelectrode thickness at which the sensitivity is maximum for Escherichia coli. The microchannel depth affects the sensitivity of the device when it is below 10 μm, approximately. The sensitivity increases when the biosensor is made with low-permittivity materials. A maximum percentage change in capacitance of around 46% was obtained by covering the total sensing area with bacteria.