Flexible Au-Pt-vertical graphene neural microelectrode for the rapid detection of steady-state and transient dopamine in rats.

Dopamine (DA) can serve as a biomarker to evaluate emotional and cognitive disorders; however, the correlation between transient and steady-state DA levels in the brain remains unclear. In this study, gold and platinum co-doped vertical graphene (AuPt-VG) is deposited onto the surface of carbon fibers (CFs) to prepare flexible neural microwires for DA detection. The diameter of the AuPt-VG/CFs is approximately 8.5 ± 0.5 μm. When using approximately thirty microwires, a detection limit of 7.6 nM is achieved in fast-scan cyclic voltammetry (FSCV). Owing to its excellent biocompatibility, antipollution ability, high selectivity, and sensitivity, the AuPt-VG microelectrode can be implanted in rats to detect DA in the blood and brain. A correlation model between differential pulse voltammetry and FSCV is established using the AuPt-VG microelectrodes, and an electrochemical analysis software is developed to track steady-state and transient DA levels in rat and PC12 nerve cells. The electrochemical test box using the AuPt-VG microelectrode provides a new method for rapid in vitro analysis of DA levels. With the adjustable performance and high biocompatibility, AuPt-VG/CFs demonstrate excellent potential for the selective detection of neurotransmitters in the blood and brain.