Experimental and simulation studies of bioinspired Au-enhanced copper single atom catalysts towards real-time expeditious dopamine sensing on human neuronal cell

Single atom catalysts (SACs) becoming important participants in biosensing owing to their characteristics such as dispersed metal active sites, signal amplification, and acceptable sensitivity and selectivity toward distinct biomolecules. A recent advancement is the extension of SACs to form dual-metal single atom catalysts with high metal loading and flexible active sites, thus enhancing the electrochemical activity and biosensing ability. This study reports carbon-supported dual-metal single atoms, bioinspired from barnacle shell-extracted chitosan, for electrochemically detecting dopamine in real-time cellular environments and biofluids. Single copper and gold atoms anchored on bioinspired chitosan-extracted carbon (CuAu SACs/BC) based electrode was fabricated and used for the selective and sensitive detection of nanomolar dopamine in biological and cellular environments. Density functional theory calculations revealed that dopamine is predominantly sensed by single Cu atoms, together with the signal enhancement by single Au atoms. Collectively, the CuAu SACs/BC-based detection platform enabled real-time dopamine detection in neuronal cells upon triggering by a precursor with good biocompatibility and nanomolar sensitivity in male, female geriatric plasma. Thus, this study demonstrated the effective utilization of bioinspired carbon with dual-metal single atom catalysts to develop promising real-time electrochemical biosensors.