Biomonitoring and Sensoring Group, Groningen University, The Netherlands.
Biosens Bioelectron. 2012 Mar 15;33(1):260-6. doi: 10.1016/j.bios.2012.01.019. Epub 2012 Jan 24.
Monitoring of extracellular brain glutamate concentrations by intracerebral biosensors is a promising approach to further investigate the role of this important neurotransmitter. However, amperometric biosensors are typically hampered by Faradaic interference caused by the presence of other electroactive species in the brain, such as ascorbic acid, dopamine, and uric acid. Various permselective membranes are often used on biosensors to prevent this. In this study we evaluated the most commonly used membranes, i.e. nafion, polyphenylenediamine, polypyrrole, polyaniline, and polynaphthol using a novel silica-based platinum electrode. First we selected the membranes with the highest sensitivity for hydrogen peroxide in vitro and an optimal selectivity against electrochemical interferents. Then we evaluated the performances of these membranes in a short lasting (3-4h) in vivo experiment. We found that best in vitro performance was accomplished with biosensors that were protected by a poly(m-phenylenediamine) membrane deposited onto the platinum electrode by cyclic voltammetry. However, post-implantation evaluation of these membranes showed poor selectivity against dopamine. Combination with a previously applied nafion layer did not protect the sensors against acute biofouling; indeed it was even counter effective. Finally, we investigated the ability of our biosensors to monitor the effect of glutamate transport blocker DL-TBOA on modulating glutamate concentrations in the prefrontal cortex of anaesthetized rats. The optimized biosensors recorded a rapid 35-fold increase in extracellular glutamate, and are considered suitable for further exploration in vivo.
通过颅内生物传感器监测细胞外脑谷氨酸浓度是进一步研究这种重要神经递质作用的有前途的方法。然而，电流生物传感器通常受到脑内其他电活性物质（如抗坏血酸、多巴胺和尿酸）存在引起的法拉第干扰的阻碍。通常在生物传感器上使用各种选择透过性膜来防止这种情况。在这项研究中，我们使用新型二氧化硅铂电极评估了最常用的膜，即 Nafion、聚苯二胺、聚吡咯、聚苯胺和聚萘酚。首先，我们选择了对体外过氧化氢具有最高灵敏度和对电化学干扰具有最佳选择性的膜。然后，我们在持续时间较短（3-4 小时）的体内实验中评估了这些膜的性能。我们发现，通过循环伏安法将聚（间苯二胺）膜沉积在铂电极上保护的生物传感器在体外表现出最佳性能。然而，这些膜的植入后评估表明，它们对多巴胺的选择性较差。与先前应用的 Nafion 层结合并没有保护传感器免受急性生物污垢的影响；实际上甚至是相反的效果。最后，我们研究了我们的生物传感器监测谷氨酸转运体阻滞剂 DL-TBOA 调节麻醉大鼠前额叶皮质中谷氨酸浓度的能力。优化后的生物传感器记录到细胞外谷氨酸迅速增加 35 倍，被认为适合进一步在体内探索。
