Chitosan–ionic liquid modified single-use sensor for electrochemical monitoring of sequence-selective DNA hybridization

Chitosan-(CHIT) and ionic liquid- (1-butyl-3-methylimidazolium hexafluorophosphate (IL)) modified single-use graphite electrodes (PGEs) were developed for the first time in the present study for the enhanced monitoring of DNA, and also for sequence-selective DNA hybridization by measuring the guanine oxidation signal. The electrochemical behaviour of the CHIT–IL modified electrodes was first investigated (with unmodified electrodes as controls) using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Sequence-selective DNA hybridization related to Hepatitis B virus (HBV) was also evaluated in the case of hybridization between amino-linked HBV probe and its complementary (target), a noncomplementary (NC) sequence, single base mismatch (MM), and also in the medium of target/mismatch (MM) mixtures (1:1). CHIT–IL modified PGEs presented a very effective discrimination of DNA hybridization owing to their superior selectivity and sensitivity.