An Electrochemical DNA Sensor for Doxorubicin Based on Graphene Oxide, Electropolymerized Azure A, and Methylene Green Composites

A voltammetric DNA sensor is developed for the determination of doxorubicin, the signal of which is the change in the current of the redox mediator Methylene green, recorded by cyclic voltammetry on a glassy carbon electrode modified by electrochemically reduced graphene oxide, electropolymerized Azure A, and DNA saturated with Methylene green. The influence of the nature of the polymer layer and the redox mediator used on the sensitivity of the determination of doxorubicin is revealed. With an optimal composition of the surface layer, the DNA sensor allows the determination of up to 0.01 pM of doxorubicin. The sensor was tested on a number of model (artificial urine, Ringer−Locke solution, bovine serum albumin solution) and biological samples (saliva, urine) containing doxorubicin.