Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA.
Department of Biomedical Engineering and Institute for Quantitative Health Science and Engineering, East Lansing, MI 48824, USA.
Biosensors (Basel). 2023 May 25;13(6):576. doi: 10.3390/bios13060576.
Neurotransmitter release is important to study in order to better understand neurological diseases and treatment approaches. Serotonin is a neurotransmitter known to play key roles in the etiology of neuropsychiatric disorders. Fast-scan cyclic voltammetry (FSCV) has enabled the detection of neurochemicals, including serotonin, on a sub-second timescale via the well-established carbon fiber microelectrode (CFME). However, poor chronic stability and biofouling, i.e., the adsorption of interferent proteins to the electrode surface upon implantation, pose challenges in the natural physiological environment. We have recently developed a uniquely designed, freestanding, all-diamond boron-doped diamond microelectrode (BDDME) for electrochemical measurements. Key potential advantages of the device include customizable electrode site layouts, a wider working potential window, improved stability, and resistance to biofouling. Here, we present a first report on the electrochemical behavior of the BDDME in comparison with CFME by investigating in vitro serotonin (5-HT) responses with varying FSCV waveform parameters and biofouling conditions. While the CFME delivered lower limits of detection, we also found that BDDMEs showed more sustained 5-HT responses to increasing or changing FSCV waveform-switching potential and frequency, as well as to higher analyte concentrations. Biofouling-induced current reductions were significantly less pronounced at the BDDME when using a "Jackson" waveform compared to CFMEs. These findings are important steps towards the development and optimization of the BDDME as a chronically implanted biosensor for in vivo neurotransmitter detection.
神经递质释放对于研究神经疾病和治疗方法至关重要。血清素是一种神经递质，已知在神经精神疾病的发病机制中起关键作用。快速扫描循环伏安法（FSCV）通过成熟的碳纤维微电极（CFME）能够在亚秒级时间尺度上检测神经化学物质，包括血清素。然而，较差的慢性稳定性和生物污垢（即在植入时电极表面吸附干扰蛋白）在自然生理环境中构成了挑战。我们最近开发了一种独特设计的、独立的、全金刚石掺硼金刚石微电极（BDDME），用于电化学测量。该器件的关键潜在优势包括可定制的电极位置布局、更宽的工作电位窗口、改善的稳定性和抗生物污垢性。在这里，我们通过研究不同 FSCV 波形参数和生物污垢条件下的体外血清素（5-HT）响应，首次报告了 BDDME 的电化学行为与 CFME 的比较。虽然 CFME 提供了更低的检测限，但我们还发现 BDDME 对增加或改变 FSCV 波形切换电位和频率以及更高的分析物浓度表现出更持续的 5-HT 响应。与 CFME 相比，BDDME 在使用“Jackson”波形时，生物污垢引起的电流减少明显不那么明显。这些发现是朝着开发和优化 BDDME 作为用于体内神经递质检测的慢性植入生物传感器迈出的重要步骤。
