Construction of non-enzymatic sensor based on porous carbon matrix loaded with Pt and Co nanoparticles for real-time monitoring of cellular superoxide anions

Quantification of superoxide anions (O 2 − ) is of great significance for the pathological research of many diseases. In this work, a non-enzymatic electrochemical sensor for superoxide sensing was fabricated on the basis of metal-organic frameworks (MOFs)-derived porous carbon matrix loaded with Pt and Co nanoparticles (denoted as Pt-Co-PC). Zeolitic imidazolate framework-67 (ZIF-67) was utilized as the precursor through a one-step calcination under N 2 atmosphere to prepare cobalt nanoparticles-porous carbon composites (denoted as Co-PC). Pt-Co-PC was then obtained by using a facile galvanic replacement procedure with Co-PC and chloroplatinic acid solution. Furthermore, the home-made screen printed gold electrodes (SPGEs) were used to immobilize the as-synthesized materials, constructing Pt-Co-PC modified electrochemical sensors. The recommended Pt-Co-PC/SPGE sensors exhibit excellent electrochemical performance for the detection of O 2 − with an extremely low detection limit of 0.118 μM (S/N = 3) and a high sensitivity of 6.218 × 10 −4  mA μM −1  cm −2 . Meanwhile, the proposed sensors possess superior reproducibility and stability. More importantly, our sensors have successfully captured the electrochemical signals of O 2 − released from Hela cells, which means the fabricated sensors have potential application of monitoring O 2 − in pathological and biological fields.