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 (R 2  = 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.