Highly anti-interference electrocatalytic sensing for dopamine with nitrogen-doped graphdiyne directly in biofluids

Nitrogen-doped graphdiyne (N-GDY) nanostructures are attracting increasing attention in electrochemical sensing field owing to its peculiar chemical structure, high structure defects, good electrical conductivity, favorable biocompatibility and hydrophilicity. A highly anti-interference electrocatalytic sensor based on N-GDY for the detection of dopamine (DA), a crucial neurotransmitter and chemical substance for numerous physiological processes, was demonstrated. The highly anti-interference ability was endowed by the abundant existing sp-N interactive sites on synthesized N-GDY surface that not only offered the very high-efficiency interactions between target DA molecules and developed interface but also effectively excluded other interferential component combinations which further powerfully boosted the high selectivity of fabricated sensor. Density functional theory (DFT) calculations were used to explore, verify and reveal both the best-matched sp-N interactive sites for DA molecules on N-GDY surface and the correlative mechanism for electrocatalytic process towards DA. Electrocatalytic sensitivity was also enhanced due to the large electroactive surface area, more active sites, superior conductivity, and improved interfacial charge transfer of as-prepared N-GDY nanostructure. Such developed sensor achieved highly selective and sensitive DA detection with a very wide linear ranging from 1 to 550 µM and a low limit of detection (LOD) of 0.46 µM, even in the real complex biofluids, where a good deal of biological components are co-existing. The superior performance towards target was principally attributed to its outstanding anti-interference ability and the analysis results in biofluids markedly declared its powerful potential for practical applications of such DA sensor.