Sensitive detection of superoxide anion released from living cells using silver nanoparticles and functionalized multiwalled carbon nanotube composite

Considering the crucial roles of superoxide anion (O 2 − ) in pathological conditions, it is of great urgency to establish a reliable approach for real-time determination of O 2 − . Herein, a sensitive non-enzymatic sensor was constructed based on silver nanoparticles (AgNPs) and sodium dodecyl sulfate functionalized carbon nanotubes (SDS-MWCNTs) composites to measure the release of O 2 − from living cells. As an analytical and sensing platform, the AgNPs/SDS-MWCNTs modified glassy carbon electrode exhibited excellent electrochemical performance toward O 2 − with a determination limit as low as 0.0897 nM and wide linear range of 6 orders of magnitude, which was superior to other O 2 − electrochemical sensors. The excellent performance was attributed to the SDS-MWCNTs composites being used as effective load matrix for the deposition of AgNPs. Importantly, this novel non-enzymatic sensor could be applied to determination of O 2 − released from living cells, and the amount of flux of O 2 − increased accordingly with the improving of the concentration of AA, which has the possibility of application in clinical diagnostics to assess oxidative stress of living cells.