Biofouling and performance of boron-doped diamond electrodes for detection of dopamine and serotonin in neuron cultivation media

•Performance of boron-doped diamond assessed in neuron cultivation media Neurobasal.•Polished surface enabled low detection limits: 2 μM (dopamine), 0.2 μM (serotonin)•Oxidized surface provided 2-times higher detection limits, but better repeatability.•Electrode surface fouling observed in Neurobasal with peptides-containing supplements.•Neurotransmitters spikes (1–2 μM) detected by amperometry in cell cultivation media. Boron doped diamond has been considered as a fouling-resistive electrode material for in vitro and in vivo detection of neurotransmitters. In this study, its performance in electrochemical detection of dopamine and serotonin in neuron cultivation media Neurobasal™ before and after cultivation of rat neurons was investigated. For differential pulse voltammetry the limits of detection in neat Neurobasal™ medium of 2 µM and 0.2 µM for dopamine and serotonin, respectively, were achieved on the polished surface, which is comparable with physiological values. On oxidized surface twofold higher values, but increased repeatabilities of the signals were obtained. However, in Neurobasal™ media with peptides-containing supplements necessary for cell cultivation, the voltammograms were notably worse shaped due to biofouling, especially in the medium isolated after neuron growth. In these complex media, the amperometric detection mode at +0.75 V (vs. Ag/AgCl) allowed to detect portion-wise additions of dopamine and serotonin (as low as 1–2 µM), mimicking neurotransmitter release from vesicles despite the lower sensitivity in comparison with neat NeurobasalTM. The results indicate substantial differences in detection on boron doped diamond electrode in the presence and absence of proteins, and the necessity of studies in real media for successful implementation to neuron-electrode interfaces.