Methyl nicotinate biomarker of tuberculosis voltammetrically detected on cobalt nanoparticle-dispersed reduced graphene oxide-based carbon film in blood

Abstract

Methyl nicotinate (MN), a metabolite of Mycobacterium tuberculosis, is an important biomarker of tuberculosis (TB). An effective measurement of MN can provide an early detection of TB, before it becomes life threatening. In this study, a cobalt (Co) and reduced graphene oxide (rGO) dispersed N-doped phenolic polymer precursor-based carbon film is used as the biosensor electrode to detect and measure MN in human blood for the first time. The Co nanoparticles are successfully used as the nonbiological recognition element of MN. Doping of the carbon film with N-heteroatom using melamine increases the film electro-conductivity. Using differential pulse voltammetry, the sensor electrode exhibits excellent linearity (0.9925) over 0.05–14 mg L−1 MN concentrations (S/N ratio = 3), with high sensitivity (1735.2 μA mM−1 cm−2) and low detection limit (0.0004 mM). The sensor also shows good selectivity and high recovery for MN. Most importantly, the sensor successfully confirms its clinical applicability when tested in the synthetic clinical MN solutions (RSD < 6.5%). The method and materials developed in this study have paved a new platform for developing similar biosensors using non-biological components for chronic diseases such as typhoid and kidney-dysfunction.