Two kinds of carbon-based nanozymes were constructed from the same precursor of zeolitic imidazolate framework-8 (ZIF-8) for O2•− determination. Hollow carbon cubic nanomaterial (labelled as HCC) was obtained by chemically etching ZIF-8 with tannic acid and a subsequent calcination. A porous carbon cubic nanomaterial (labelled as PCC) was prepared by directly pyrolysis. Then HCC and PCC were immobilized on the surface of screen printed carbon electrodes (SPCE), fabricating HCC and PCC modified electrodes (denoted as HCC/SPCE and PCC/SPCE). HCC/SPCE, best operated at −0.5 V (vs. Ag/AgCl), has a sensitivity of 6.55 × 102 nA μM−1 cm−2 with a detection limit of 207 nM (at S/N = 3) for O2•− sensing. And PCC/SPCE, best operated at −0.4 V (vs. Ag/AgCl), exhibited a superior performance for O2•− detection with a sensitivity of 1.14 × 103 nA μM−1 cm−2 and a low detection limit of 140 nM (at S/N = 3). The two sensors possess excellent reproducibility and stability. They were used to sense O2•− released from HeLa cells. [Figure not available: see fulltext.].
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Acknowledgements This research was financially supported by the Science and Technology Commission of Shanghai Municipality (STCSM, No. 16520710800) and the Fundamental Research Funds for the Central Universities (No. 50321101917022).
© 2019, Springer-Verlag GmbH Austria, part of Springer Nature.
- Carbon-based nanozymes
- Metal-organic frameworks
- Non-enzymatic sensors
- Screen printed carbon electrodes
- Zeolitic imidazolate framework