Electrochemical sensing of hydrogen peroxide using a glassy carbon electrode modified with multiwalled carbon nanotubes and zein nanoparticle composites: application to HepG2 cancer cell detection

A nanobiocomposite was prepared from multiwalled carbon nanotubes and zein nanoparticles. It was dispersed in water/ethanol and drop cast onto a glassy carbon electrode. The modified electrode can be used for electroreduction of H2O2 (typically at a working potential of -0.71 V vs. Ag/AgCl). The electrochemical properties of the electrode were investigated by cyclic voltammetry, linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Response to H2O2 is linear in the 0.049 to 22 mu M concentration range, and the detection limit is 35 nM at pH 7.0. The sensor was successfully utilized for the measurement of H2O2 in a synthetic urine sample, and for monitoring the release of H2O2 from human dermal fibroblasts and human hepatocellular carcinoma cells. Graphical abstract Schematic representation of a novel metal- and enzyme-free electrochemical nanosensor. A glassy carbon electrode was modified with a nanocomposite prepared from multiwalled carbon nanotubes and zein nanoparticles. It was applied to the identification of liver cancer cells via sensing of H2O2 and has a very low detection limit.