Abstract
BACKGROUND: Carbon nanotube (CNT) fiber directly spun from an aerogel has a unique, wellโaligned nanostructure (nanoโpore and nanoโbrush), and thus provides high electroโcatalytic activity and strong interaction with glucose oxidase enzyme. It shows great potential as a microelectrode for electrochemical biosensors.
RESULTS: Cyclic voltammogram results indicate that postโsynthesis treatments have great influence on the electrocatalytic activity of CNT fibers. Raman spectroscopy and electrical conductivity tests suggest that fibers annealed at 250 ยฐC remove most of the impurities without damaging the graphiteโlike structure. This leads to a nanoโporous morphology on the surface and the highest conductivity value (1.1 ร 10^5^ S m^โ1^). Two CNT fiber microelectrode designs were applied to enhance their electron transfer behaviour, and it was found that a design using a 30 nm gold coating is able to linearly cover human physiological glucose level between 2 and 30 mmol L^โ1^. The design also leads to a low detection limit of 25 ยตmol L^โ1^.
CONCLUSIONS: The high performance of CNT fibers not only offers exceptional mechanical and electrical properties, but also provides a large surface area and electron transfer pathway. They consequently make excellent bioactive microelectrodes for glucose biosensing, especially for potential use in implantable devices. Copyright ยฉ 2011 Society of Chemical Industry