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

•Small-sized AgNPs uniformly deposited SDS functionalized carbon nanotube.•Fabricated a novel non-enzymatic O2− sensor based on AgNPs/SDS-MWCNTs/GCE.•A remarkable low detection limit of 8.97 × 10−11 M was achieved.•The sensor can measure the release of O2− from living cells directly, and is AA dose-dependent manner.

Considering the crucial roles of superoxide anion (O2−) in pathological conditions, it is of great urgency to establish a reliable approach for real-time determination of O2−. 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 O2− from living cells. As an analytical and sensing platform, the AgNPs/SDS-MWCNTs modified glassy carbon electrode exhibited excellent electrochemical performance toward O2− with a determination limit as low as 0.0897 nM and wide linear range of 6 orders of magnitude, which was superior to other O2− 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 O2− released from living cells, and the amount of flux of O2− 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.

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