Chitosan bio-functionalization of carbon nanotube arrayed electrode

Adv. Mater. Lett., 2017, 8 (12), pp 1166-1170

DOI: 10.5185/amlett.2017.1577

Publication Date (Web): Sep 08, 2017

Copyright © IAAM-VBRI Press

Abstract

Nanostructured electrodes enable a new generation of electrochemical sensors by increasing their surface area that lead to stronger signals generated by electrochemically-active molecules, such as diagnostic redox-active biomarkers. Yet, the selectivity of these translational sensors is far from being sufficient for discriminating between individual molecules in multicomponent samples, such as biofluids. Here, we propose an approach to improve the selectivity of nanostructured electrodes using a simple modification with a functional bio-polymer. Specifically, we demonstrate the targeted modification with a bio-polymer chitosan of carbon nanotubes organized in an array on a Au electrode. We describe the fabrication process and we show the characterization of the structural morphology and the electrochemical activity of the fabricated chitosan-modified carbon nanotube arrayed electrode. Electrochemical characterization yielded an increased effective surface area for the optimized carbon nanotube arrayed electrode (0.46 ± 0.03 cm²) that was similar to the area of the unmodified Au electrode (0.48 ± 0.02 cm²). Furthermore, despite decreased electrochemical current characteristics, we demonstrate the feasibility to modify individual carbon nanotubes with chitosan. The modification of the carbon nanostructures with chitosan will enable further functionalization with specific receptors, such as enzymes and antibodies that will provide the required selectivity towards biomarkers in multicomponent biofluids. 

Keywords

Electrochemical sensors, chitosan, carbon nanotubes, modified electrodes.