A sensitively non-enzymatic amperometric sensor and its application in living cell superoxide anion radical detection

Here, we report a nanocomposite composed of silver nanoparticles and multi-walled carbon nanotubes (AgNPs/MWNTs) utilized as an efficient electrode material for sensitive detection superoxide anion (O₂^•-). The procedure to synthesize AgNPs/MWNTs nanocomposites was green and facile. In the presence of functionalized multi-wall carbon nanotubes (MWNTs), silver nanoparticles (AgNPs) were in situ generated by chemical reduction of silver nitrate with glucose as a reducing and stabilizing agent to give the desired AgNPs/MWNTs nanocomposites. The nanocomposites can be easily used for the construction of an electrochemical sensor on glassy carbon electrode (GCE). The characterization of sensor and experimental parameters affecting its activity were investigated employing scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), X-ray diffraction (XRD), and cyclic voltammetry (CV). The resulted sensor exhibited favorable electrochemical performance for O₂^•- sensing with a low detection limit of 0.1192 nM and wide linear range of 6 orders of magnitude, which guarantees the capacity of sensitive and credible detection of O₂^•- released from living cells. Notably, a simulation experiment indicated the capacity to resist oxidative stress is limited in biological milieu. Thus this work has great potential for further applications in biological researches.