This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleic acid (RNA) sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface, and the attachment of thiolated RNA to the bound nanoparticles.

The application of the compounded nanomaterials for sensor development has the distinct advantage of retaining the electrical behavior property of carbon nanotubes and, through the gold nanoparticles, incorporating an increased surface area for additional analyte attachment sites, thus increasing sensitivity. We successfully demonstrated that the coating of gold nanoparticles with a selective RNA sequence increased the capture of E. coli by 189% when compared to uncoated particles.

The approach to sensor formation detailed in this study illustrates the great potential of unique composite structures in the development of a multi-array, electrochemical sensor for the fast and sensitive detection of pathogens.