Interdigitated electrode biosensor on graphene oxide-multiwalled carbon nanotubes for DNA detection

Abstract

interdigitated electrodes (IDEs) with GO-MWCNTs thin film as sensing membrane have been successfully developed on silicon substrate for DNA detection. The physical surface morphology of GO-MWCNTs were characterized using field emission scanning electron microscopy (FESEM) and the surface structural was determined by X-ray powder diffraction (XRD). The chemical bonding of GO-MWCNTs were examined by using Fourier transform infrared spectroscopy (FTIR). FTIR spectrum successfully shows that the GO-MWCNT hybrid thin film contained carboxyl functional groups by showing peaks at 3375cm -1 and 1690cm -1 for (O-H stretch), and (C=O stretch) respectively. The IDE biosensor was measured on DNA immobilization activities. The current of the IDE after the immobilization at 2V was drop from 0.9mA to 0.75mA. The difference of the current signal is due to the negatively charged backbones of the DNA probes repelled electrons from accumulating at the conducting channel. The IDE current was further decreased when the DNA hybridization took place.