Design of an interdigitated microelectrode biosensor using a-SiC:H surface to capture E. coli

This work proposes an interdigitated microelectrode biosensor (IMB), which includes hydrogenated amorphous silicon carbide (a-SiC:H) as surface to be functionalized. Accordingly, two a-SiC:H films are included, one on top of SiO₂, and another on top of microelectrodes. The design along with the medium were simulated on CoventorWare^® software, taking into account that the IMB proposed will be for the detection of Escherichia coli. The influence of both the a-SiC:H thin film and the capture of bacteria on electrodes on the impedance spectroscopy of the biosensor in the range of 10 kHz to 100 MHz was studied. The results show that the higher the conductivity of the thin film on microelectrodes, the lower is the increase of the magnitude of the impedance spectrum measured in presence of the sterile blank solution, and that the capture of bacteria on microelectrodes increases the sensitivity. The maximum percentage change in the magnitude of impedance of the PIMB is about 45 times greater than that of the conventional interdigitated microelectrode biosensor (CIMB).