Department of Biomedical Engineering, University of Strathclyde, 106 Rottenrow East, Glasgow, UK.
Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, UK.
Anal Bioanal Chem. 2023 Mar;415(6):1137-1147. doi: 10.1007/s00216-022-04445-1. Epub 2022 Dec 2.
In this study, an implantable stereo-electroencephalography (sEEG) depth electrode was functionalised with an enzyme coating for enzyme-based biosensing of glucose and L-glutamate. This was done because personalised medicine could benefit from active real-time neurochemical monitoring on small spatial and temporal scales to further understand and treat neurological disorders. To achieve this, the sEEG depth electrode was characterised using cyclic voltammetry (CV), differential pulse voltammetry (DPV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) using several electrochemical redox mediators (potassium ferri/ferrocyanide, ruthenium hexamine chloride, and dopamine). To improve performance, the Pt sensors on the sEEG depth electrode were coated with platinum black and a crosslinked gelatin-enzyme film to enable enzymatic biosensing. This characterisation work showed that producing a useable electrode with a good electrochemical response showing the expected behaviour for a platinum electrode was possible. Coating with Pt black improved the sensitivity to HO over unmodified electrodes and approached that of well-defined Pt macro disc electrodes. Measured current showed good dependence on concentration, and the calibration curves report good sensitivity of 29.65 nA/cm/μM for glucose and 8.05 nA/cm/μM for L-glutamate with a stable, repeatable, and linear response. These findings demonstrate that existing clinical electrode devices can be adapted for combined electrochemical and electrophysiological measurement in patients and obviate the need to develop new electrodes when existing clinically approved devices and the associated knowledge can be reused. This accelerates the time to use and application of in vivo and wearable biosensing for diagnosis, treatment, and personalised medicine.
在这项研究中，一种可植入的立体脑电图（sEEG）深度电极被酶涂层功能化，用于基于酶的葡萄糖和 L-谷氨酸的生物传感。之所以这样做，是因为个性化医疗可能受益于主动实时神经化学监测小空间和时间尺度，以进一步了解和治疗神经疾病。为了实现这一目标，使用循环伏安法（CV）、差分脉冲伏安法（DPV）、方波伏安法（SWV）和电化学阻抗谱（EIS）对 sEEG 深度电极进行了表征，使用了几种电化学氧化还原介体（铁氰化钾/亚铁氰化钾、六氨合钌氯化物和多巴胺）。为了提高性能，sEEG 深度电极上的 Pt 传感器用铂黑和交联明胶-酶膜进行了涂层，以实现酶生物传感。这项特性研究表明，制造具有良好电化学响应的可用电极，表现出铂电极的预期行为是可能的。Pt 黑的涂层提高了对 HO 的灵敏度，优于未修饰电极，并接近定义良好的 Pt 宏观盘电极。测量电流对浓度表现出良好的依赖性，校准曲线报告了葡萄糖的高灵敏度为 29.65 nA/cm/μM 和 L-谷氨酸的 8.05 nA/cm/μM，具有稳定、可重复和线性的响应。这些发现表明，现有的临床电极设备可以适应患者的电化学和电生理联合测量，并且可以避免在可以重复使用现有临床批准的设备和相关知识时开发新的电极。这加速了体内和可穿戴生物传感在诊断、治疗和个性化医疗中的应用和应用时间。
