Increased redox-active peptide loading on carbon nanotube electrodes

Carbon nanotube (CNT) electrodes for electrochemistry were fabricated from single- and double-walled carbon nanotubes. The electrodes were subsequently covalently loaded with a ferrocene modified α-aminoisobutyric acid peptide, and the electron transfer (ET) capabilities were probed with cyclic voltammetry. The CNT electrodes comprised of double walled CNTs (DWCNTs) demonstrated significantly higher peak current compared to their single walled counterparts (SWCNTs). This is attributed to a higher loading of the ferrocene modified peptide to the outer wall of the nanotube, through the presence of a larger number of defects sites within the sp2 carbon lattice for the DWCNTs. This higher loading was achieved without compromising the ET rate, indicating that DWCNTs may offer a useful alternative to SWCNTs in future electrochemical sensors and biosensors.

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► Double and single walled carbon nanotubes (DWCNT and SWCNT) were assembled on gold surfaces.
► CNT arrays were decorated with a ferrocene modified α-aminoisobutyric acid protein.
► A higher loading of redox protein was achieved in the DWCNT case.
► DWCNT electrode exhibited faster electron transfer kinetics.
► DWCNTs may be superior to SWCNTs in sensors and biosensing devices.