▎ 摘　　要

The development of microelectrodes for the rapid in situ detection of neurotransmitters and their metabolic levels in human biofluids has considerable significance in biomedical research. In this study, self-supported graphene microelectrodes with B-doped, N-doped, and B-and N-co-doped vertical graphene (BVG, NVG, and BNVG, respectively) nanosheets grown on horizontal graphene (HG) were fabricated for the first time. The high electrochemical catalytic activity of BVG/HG on monoamine compounds was explored by investigating the in-fluence of B and N atoms and the VG layer thickness on the response current of neurotransmitters. Quantitative analysis using the BVG/HG electrode in a blood-like environment with pH 7.4 indicated that the linear con-centration ranges were 1-400 and 1-350 mu M for dopamine (DA) and serotonin (5-HT), with limits of detection (LODs) of 0.271 and 0.361 mu M, respectively. For tryptophan (Trp), the sensor measured a wide linear concen-tration range of 3-1500 mu M over a wide pH range of 5.0-9.0, with the LOD fluctuating between 0.58 and 1.04 mu M. Furthermore, the BVG/HG microelectrodes could be developed as needle-and pen-type sensors for the detection of DA, 5-HT, and Trp in human blood and gastrointestinal secretion samples.