Electrochemical determination of neurotransmitter serotonin using boron/nitrogen co-doped diamond-graphene nanowall-structured particles

Electrode fouling is a major issue in biological detection due to the adhesion of the protein itself and polymer-ization of biomolecules on the electrode surface, impeding the electron transfer ability and decreasing the cur-rent response. To overcome this issue, the use of anti-fouling material, especially boron-doped diamond (BDD) electrode, is an alternative way. However, the electrocatalytic activity of BDD is inadequate compared with graphene nanowalls, or other sp2 phase materials. Furthermore, the contamination from other metals during the synthesis of BDD can affect the electrochemical analysis. Herein, for the first time, we report boron/nitro-gen co-doped with diamond graphene nanowalls (DGNW) integrated with the screen-printed graphene elec-trode (SPGE) for the detection of serotonin (5-HT) as a model system. DGNW shows the integration of sp2 and sp3 hybridized phases, leading to a high surface area, high electrocatalytic activity, wide potential window, and a low background current. DGNWs prepared under different conditions were investigated and character-ized. Compared to the bare SPGEs, the DGNW modified electrode exhibited good electrochemical performance and a superior anti-fouling ability for neurotransmitter detection. A significant enhancement in current response in a concentration-dependent manner was obtained using differential pulse voltammetry (DPV) in the presence of 5-HT from 1 to 500 mu M (R2 >0.99) with a low detection limit (0.28 mu M). Moreover, this pro-posed method was applied ina synthetic urine sample to confirm its biological applicability. These results show that the DGNW modified electrode could be productively utilized as an alternative electrochemical transducer with a good anti-fouling performance.

Automated summary

This study reports the integration of boron/nitrogen co-doped diamond graphene nanowalls (DGNW) with screen-printed graphene electrode (SPGE) for the detection of serotonin. The DGNW-modified electrode exhibits high surface area, high electrocatalytic activity, wide potential window, and low background current. It shows good anti-fouling ability and significant current response enhancement, making it suitable for neurotransmitter detection.