Enzyme-free electrochemical sensor based on ZIF-67 for the detection of superoxide anion radical released from SK-BR-3 cells.

Developing nanomaterials as alternatives of enzymes is of great significance to realize qualification and quantitation of superoxide anion (O 2 −), which has been proved to play a crucial role in physiological condition. In this work, a novel electrochemical catalyst of cobalt nanoparticle doped porous cubic carbon (Co-PCC) was prepared through the calcination of zeolitic imidazolate framework-67 (ZIF-67), which was obtained from one-step synthesis. Then Co-PCC was used to construct enzyme-free electrochemical sensor for the detection of O 2 −. The response of H 2 O 2 , though much lower than that of O 2 −, was also caught by the Co-PCC/SPCE. The fabricated sensor exhibited obvious response towards O 2 − in the range of 0.8–76.8 μM (R2 = 0.997) with a high sensitivity of 3.59 × 10−4 mA μM−1 cm−2 and a limit of detection of 0.41 μM (S/N = 3). In addition, the proposed sensor can be used to detect O 2 − released from SK-BR-3 cells, which makes it possible to monitor the dynamic change of O 2 − in living cells. Unlabelled Image • Enzyme-free electrochemical sensor was developed for in-house electrochemical analysis. • A novel SOD-mimic nanozyme based on ZIF-67 was obtained from one-step synthesis. • The established sensor was used for electrochemical sensing of superoxide anions released from living cell. [ABSTRACT FROM AUTHOR]