Investigation of a DNA‐Based Biosensor with Chitosan‐Carbon Nanotubes Interface by Cyclic and Elimination Voltammetry

The paper presents a disposable DNA biosensor based on a composite of multiwalled carbon nanotubes (MWCNT) in chitosan (CHIT) used as an interface at the screen printed carbon electrode (SPCE). Double stranded herring sperm DNA was immobilized over the MWCNT‐CHIT layer. The response of the modified SPCE with and without DNA was characterized using the redox probe [Fe(CN) 6 ] 3−/4− in the mode of cyclic voltammetry and elimination voltammetry with linear scan (EVLS), which enables the elimination of selected partial voltammetric currents contributing to the total current. The elimination functions providing a significant increase in the voltammetric current sensitivity and improving the peak resolution enable to indicate an adsorbed state of depolarizers, to discover hidden electrode processes, and to determine their nature. The SPCE surface modification was evaluated using (a) the charge transfer coefficient α of the redox probe calculated from the Tafel plot analysis (TPA) and EVLS and (b) the polarization resistance R P for both cathodic and anodic processes.