Single-atom electrocatalysis: a new approach to in vivo electrochemical biosensing

Modulation of interfacial electron transfer has been proven to pave a new approach to in vivo electrochemical monitoring of brain chemistry;however,designing and establishing highly efficient electrocatalytic scheme towards neurochemicals remain a longstanding challenge.Here,we find that recently established single-atom catalyst(SAC)can be used for catalyzing the electrochemical process of physiologically relevant chemicals and thus offers a new avenue to in vivo electrochemical biosensing.To prove this new concept,we used Co single-atom catalyst(Co-SAC),in which the atomic active sites are dispersed in ordered porous N-doping carbon matrix at atomic level,as an example of SACs for analyzing glucose as the physiologically relevant model chemicals.We found that Co-SAC catalyzes the electrochemical oxidation of hydrogen peroxide(H2O2)at a low potential of ca.+0.05 V(vs.Ag/AgCl).This property was further used for developing an oxidase-based glucose biosensor that was used subsequently as a selective detector of an online electrochemical system(OECS)for continuous monitoring of microdialysate glucose in rat brain.The OECS with Co-SAC-based glucose biosensor as the online detector was well responsive to glucose without interference from other electroactive species in brain microdialysate.This study essentially offers a new approach to in vivo electrochemical analysis with SACs as electrocatalysts to modulate interfacial electron transfer.