Fabrication of Cobalt Nanocomposites as Enzyme Mimetic with Excellent Electrocatalytic Activity for Superoxide Oxidation and Cellular Release Detection

The combination of novel materials and electrochemistry technologies can effectively detect a variety of biochemicals to facilitate understanding and monitoring of biological processes. In this study, an uncomplicated and environmentally friendly microemulsion method was developed to synthesize Co based nanocomposites (Co based NCs) containing Co-3(PO4)(2), Co(PO3)(2), Co-2(OH)PO4 and carbon structure as a nanostructured biomimetic enzyme for the detection of cellular O-2(center dot-) release. Interestingly, Co based nanocomposites can act as nanoscale biological enzymes and catalyze superoxide anion (O-2(center dot-)) oxidation at 0.2 V, which was significantly lower than the currently reported potential at 0.484 V. The designed O-2(center dot-) sensor showed a wide linearity range from 3 nM to 0.15 mu M and detection limit as low as 1.0 nM (S/N = 3). Its excellent selectivity and sensitivity toward O-2(center dot-) sensing ability allow the Co based NCs modified sensor to electrochemically monitor O-2(center dot-) release from human umbilical-vein endothelial cells (HUVECs). This result provides a reliable platform for fabricating biomimetic enzymes sensors with high sensitivity and durability in biological analysis and paves more routes for the detection of chemical signaling molecules from cells, in vivo or other biological systems.