Nanobioelectronics Laboratory, Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer Sheva, 8410501, Israel.
Nanobioelectronics Laboratory, Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer Sheva, 8410501, Israel.
Talanta. 2018 May 1;181:57-64. doi: 10.1016/j.talanta.2017.12.081. Epub 2017 Dec 28.
In vivo monitoring of the neurotransmitter dopamine can potentially improve the diagnosis of neurological disorders and elucidate their underlying biochemical mechanisms. While electrochemical sensors can detect unlabeled dopamine molecules, their sensing performance is dramatically reduced by electrochemical currents generated by other, interfering molecules (e.g., uric acid) in the biological environment. To overcome this caveat, the surface of the sensor is often modified with electrocatalytic materials, which are encapsulated inside a polymeric film; however, the effect of the encapsulating film on the sensing performance of the electrode has not been systematically studied. This study characterizes the effect of loading carbon nanotubes (CNTs) onto a chitosan film on the electrochemical sensing performance of dopamine in the presence of uric acid. Higher CNT loading increases the diffusion and electron transfer rate coefficients of the sensor and, in the presence of uric acid, provides better sensitivity (3.00µALµmol for 1.75% CNT loading, vs 0.01µALµmol for 1% loading) but a poorer limit-of-detection (2.00µmolLvs 1.00, respectively), as reported here for the first time. These findings can help optimize the sensitivity and the limit-of-detection of electrochemical sensors in complex biofluids to enable an in vivo monitoring of dopamine and other redox-active molecules.
在体监测神经递质多巴胺可以提高神经疾病的诊断水平，并阐明其潜在的生化机制。电化学传感器可以检测未标记的多巴胺分子，但在生物环境中，其他干扰分子（如尿酸）产生的电化学电流会显著降低其传感性能。为了克服这一缺陷，传感器的表面通常用电化学催化材料进行修饰，这些材料被包裹在聚合物薄膜内；然而，封装膜对电极传感性能的影响尚未得到系统研究。本研究在尿酸存在的情况下，表征了将碳纳米管 (CNT) 负载到壳聚糖膜上对多巴胺电化学传感性能的影响。较高的 CNT 负载增加了传感器的扩散和电子转移速率系数，并且在尿酸存在的情况下，提供了更好的灵敏度（1.75% CNT 负载时为 3.00µALµmol，1%负载时为 0.01µALµmol），但检测限较差（分别为 2.00µmolL和 1.00µmolL），这是首次报道。这些发现有助于优化复杂生物流体中电化学传感器的灵敏度和检测限，从而实现多巴胺和其他氧化还原活性分子的在体监测。
