Simultaneous Electrochemical and SPR Detection of Dopamine Exocytosis from Single Cells and Multiple Cells Using Au Single Atom Modified Carbon Nanopipettes

Dopamine (DA) release from single-cell exocytosis is an important biomarker for various neurodegenerative diseases such as Parkinson's disease. In situ and real-time analysis and detection of single-cell exocytosis release, as well as multiple-cell exocytosis detection reflecting collective behavior, have become important areas of research. However, currently the accuracy and sensitivity of detecting DA released by single-cell exocytosis are insufficient, while the quantitative detection of DA released by multiple-cell exocytosis has not been achieved. In this work, we modified carboxylated carbon nanopipette electrodes (c-CNPs) with Au single atoms (Au/c-CNPs), using their high atomic utilization and catalytic activity to enhance the sensitivity and accuracy of DA detection, achieving a detection limit of 0.049 μM. Additionally, DFT results proved that Au single atoms decreased the rate-determining step energy in the DA oxidation process and exhibited better catalytic activity. Then, a surface plasmon resonance (SPR) sensing platform based on aptamers was established to realize the real-time quantitative detection of DA by using the specific recognition effect of aptamers on DA. The combination of Au/c-CNPs and the SPR sensing platform enables the highly sensitive quantitative detection of DA released from exocytosis at both single- and multiple-cell levels. This study provides an efficient and reliable detection tool for the study of cell secretory behavior, which is conducive to obtaining an in-depth understanding of neurotransmitter-related biological processes and neurodegenerative diseases.