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

[Display omitted] •Boron/nitrogen co-doped DGNW was synthesized and used to modify SPEs.•First time employment of DGNW with SPEs for 5-HT sensing.•High sensitivity and good anti-fouling capability were obtained.•This sensor shows a low cost, simplicity, and broad sensing applicability.•The proposed sensor is successfully applied to detect 5-HT in synthetic urine sample. Electrode fouling is a major issue in biological detection due to the adhesion of the protein itself and polymerization of biomolecules on the electrode surface, impeding the electron transfer ability and decreasing the current 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/nitrogen co-doped with diamond graphene nanowalls (DGNW) integrated with the screen-printed graphene electrode (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 characterized. 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 μM (R2 >0.99) with a low detection limit (0.28 μM). Moreover, this proposed method was applied in a 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.