Biomimetic Polymer-Based Electrochemical Sensor Using Methyl Blue-Adsorbed Reduced Graphene Oxide and Functionalized Multiwalled Carbon Nanotubes for Trace Sensing of Cyanocobalamin

The paper reports a three-dimensional cyanocobalamin (CbL)-selective biomimetic imprinted polymer. For this, a methyl blue-adsorbed reduced graphene oxide (rGO) and functionalized multiwalled carbon nanotubes (f-MWCNTs) composite, duly functionalized with acryloylurea, was used. This exhibited higher electroconductivity and larger surface area in comparison to either pristine carbon nanotubes or graphene. It is the first synthetic biomimetic polymer of Cbl, grown on the surface of a pencil graphite electrode. In this work, the adsorption of methyl blue over the rGO sheets improved its solubility, conductivity, and self-assembly properties. Such assemblies of rGO sheets and f-MWCNTs provide enhanced kinetics and conductivity to the entire architectural design of a molecularly imprinted polymer. The ultratrace detection of Cbl was feasible by differential-pulse voltammetric transduction. This sensor exhibited high sensibility and selectivity for Cbl detection, especially in real samples.