Polyaniline as a sacrificing template for the synthesis of controlled Co3O4 nanoparticles for the sensitive and selective detection of methotrexate (MTX)

The successful monitoring of the anticancer drugs using nanostructured materials is very important but very challenging task. The uniform and controlled synthesis of metal oxide nanoparticles is highly needed in order to enhance the catalytic activity which could result into the development of sensitive and selective electrochemical devices. For this purpose, we have used a simple approach by involving polyaniline (PANI) as a sacrificing template for the growth of uniform and controlled Co 3 O 4 nanoparticles by hydrothermal method. The structure, shape, composition and phase purity were studied by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transform Infrared (FTIR) techniques. The average size of Co 3 O 4 nanoparticles was found below 50 nm. The cubic crystallography is confirmed for the Co 3 O 4 nanoparticles. The electrochemical properties of PANI-assisted Co 3 O 4 nanoparticles for methotrexate MTX drug were evaluated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) in Britton–Robinson buffer (BRB) of pH 3.5. The PANI-assisted Co 3 O 4 nanoparticles were found highly sensitive for the MTX drug and exhibited a linear range from 5 to 75 µM of MTX and limit of detection for the modified electrode was estimated 1.98 µM. The proposed electrochemical sensor is low cost, simple, highly sensitive and selective towards MTX detection. The synthetic methodology of using the conducting polymer as a sacrificing template for the growth of controlled Co 3 O 4 nanoparticles can be utilized for the wide range of electrochemical applications.