Fabrication of hierarchically porous carbon networks for the electrochemical determination of superoxide anion released from living cells

•Hierarchically porous carbon networks (HPCN) were prepared through TMB-induced self-assembly and carbonization strategy.•The introduction of TMB results in changed morphology, enriched pore structure, and improved defect degree.•The O2− sensor HPCN/SPCE has the potential to distinguish between cancer and normal cells by detecting cell-released O2−. Realizing the quantitative detection of superoxide anions (O2−) is of great significance to the pathological research based on the correlation between O2− and many diseases. Currently, the main challenge for O2− electrochemical detection in the actual sample is the development of effective nano-mimetic materials to replace natural enzymes to achieve high-selectivity detection of O2−. In this work, hierarchically porous carbon networks (HPCN) were successfully prepared through 1,3,5-trimethylbenzene (TMB)-induced self-assembly and carbonization strategy. Owing to the introduction of TMB, HPCN obtains the changed morphology, enriched pore structure, and improved defect degree, which promotes mass transfer and leads to faster electron transfer efficiency. Therefore, the non-enzymatic O2− electrochemical sensor fabricated with HPCN (denoted as HPCN/SPCE) exhibits high sensitivity (607.4 μA cm−2 mM-1) and excellent selectivity for detecting O2−. Importantly, the sensor successfully achieved the dynamic monitor of O2− released from living cells and has the potential to distinguish between cancer and normal cells.