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 (O2−), 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 O2−. The response of H2O2, though much lower than that of O2−, was also caught by the Co-PCC/SPCE. The fabricated sensor exhibited obvious response towards O2− 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 O2− released from SK-BR-3 cells, which makes it possible to monitor the dynamic change of O2− in living cells.