Multi-Wall Carbon Nanotubes Deposited on Gold Electrode for Bacteria Detection

In this paper, we describe a new strategy for E. coli bacteria detection using an immunosensor based on multi-wall carbon nanotubes (MWCNTs) deposited onto a gold electrode. Cyclic voltammetry and impedance spectroscopy were performed before and after MWCNTs deposition. The deposition of MWCNTs on the gold surface was further confirmed by obtaining transmission electron microscopy (TEM) images. The MWCNTs modified with carboxyl groups were functionalized with polyclonal antibodies and were used for E. coli detection. The specificity of the immunosensor was tested against Lactobacillus fermentium bacteria. A limit of detection of 10 CFU/mL was obtained with good reproducibility. Such a low detection limit is obtained due to the high conductivity of multiwall carbon nanotubes.