Myoglobin biofunctionalized electrochemical biosensor platform for the dual determination of nitrite and H2O2 as oxidative stress markers

The myoglobin (Mb) biofunctionalized carboxylic acid functionalized multi walled carbon nanotubes (FMWCNT) modified polypyrrole (PPy) electrodeposited screen printed carbon electrode (SPCE) showed an excellent biocatalytic activity towards the one electron redox reaction of nitrite and the reduction of H ₂ O ₂ . The direct electron transfer of the Mb immobilized into the FMWCNT was greatly facilitated. The influence of various experimental conditions was examined for the characterization of fabricated biosensor for optimum analytical performance. The each and every step of surface morphological changes were studied by scanning electron microscope (SEM) while electrochemical changes were monitored via cyclic voltammetry (CV). The voltammetric response of the fabricated biosensor platform varied linearly with varying NO ₂ ^– concentration of 0.1 to 800 µM by a detection limit 0.1 µM. Further, the electrochemical response of the constructed biosensor changed linearly into the H ₂ O ₂ concentration ranges between 1 to 600 µM by the detection limit of 0.5 µM. Moreover, a low cost electrochemical virtual cyclic voltammetric analyzer was developed based on home-made potentiostat and graphical user-interface software LabVIEW 10.0. The performance of the developed virtual analyzer has been further evaluated by applying it for the measurement of NO ₂ ^– and H ₂ O ₂ in L-NAME treated embryonic rat heart-derived H9c2 cardiomyoblasts and the results are validated with commercial electrochemical analyzer.