Application of Alizarin/Graphene-Chitosan Modified Electrode on Detection of Human Telomere DNA

In this work, the glassy carbon electrode modified by alizarin (AR) hybridized with graphene (CRG) and chitosan (CS) was prepared. The AR/CRG-CS electrode exhibited a pair of well-defined reversible redox peaks in 0.1 M phosphate buffer solution (PBS, pH 7.4) with the oxidation peak at −0.573 V and the reduction peak at −0.652 V. It exhibited a two-proton and two-electron redox process and a fast heterogeneous electron transfer rate with the rate constant ( K s ) of 1.69 s −1 using the cyclic voltammetry. Based on the characteristics of alizarin with the decreased current and negative potential shift after binding with human telomere DNA, a sensitive, simple, reliable and stable electrochemical method for the detection of human telomere DNA using the AR/CRG-CS electrode was developed. The electrochemical response showed a linear relationship with DNA concentration in the range of 8.0 × 10 −8 −1.4 × 10 −5 M ( R = 0.9995) with the linear regression equation as Δ I pc (μA) = 8.4860 + 0.5366 C (μmol) and the detection limit ( S/N ) as 2.0 × 10 −8 M.