A polymer/enzyme composite biosensor for monitoring neurochemical glutamate was performance optimised in vitro for sensitivity, selectivity and stability. This first generation Pt/glutamate oxidase-based sensor displayed appropriate sensitivity (90.4 ± 2.0 nA cm⁻² μM⁻¹). It also has ideal stability/biocompatibility with no significant decrease in response observed for repeated calibrations, exposure to electron beam sterilisation, or following storage at 4 °C either dry (28 days) or in ex-vivo rodent brain tissue (14 days). Potential non-glutamate contributing signals, generated by extracellular levels of the principal endogenous electroactive interferents, were typically <5% of the basal (10 μM) glutamate response. Changes in molecular oxygen (the natural enzyme mediator) over the normal brain tissue range of 40–80 μM had minimal effect on the glutamate signal for concentrations of 10 and 100 μM (Mean K_MO₂ = 1.86 ± 0.74 μM, [O₂]_90% = ca. 15 μM). Additionally, a low μM calculated limit of detection (0.44 ± 0.05) and rapid response time (ca. 1.67 ± 0.06 s), combined with no effect of pH and temperature changes over physiologically relevant ranges (7.2–7.6 and 34–40 °C respectively), collectively suggest that this composite biosensor should reliably detect l-glutamate when used for neurochemical monitoring. Preliminary experiments involving implantation in the striatum of freely moving rats demonstrated stable recording over several weeks, and reliable detection of physiological changes in glutamate in response to behavioural/neuronal activation (locomotor activity and restraint stress).

一种用于监测神经化学谷氨酸的聚合物/酶复合生物传感器在体外对灵敏度、选择性和稳定性进行了性能优化。该第一代基于 Pt/谷氨酸氧化酶的传感器显示出适当的灵敏度 (90.4 ± 2.0 nA cm ^-2 μM ^-1 )。它还具有理想的稳定性/生物相容性，对于重复校准、暴露于电子束灭菌或在 4°C 干燥（28 天）或离体储存后观察到的响应没有显着降低啮齿动物脑组织（14 天）。由主要内源性电活性干扰物的细胞外水平产生的潜在非谷氨酸贡献信号通常小于基础 (10 μM) 谷氨酸反应的 5%。在 40–80 μM 的正常脑组织范围内，分子氧（天然酶介质）的变化对 10 和 100 μM 浓度的谷氨酸信号影响最小（平均 K _M O ₂  = 1.86 ± 0.74 μM，[O ₂ ] _90%  = 约15 μM)。此外，低 μM 计算检测限 (0.44 ± 0.05) 和快速响应时间 ( ca.1.67 ± 0.06 s），再加上生理相关范围（分别为 7.2-7.6 和 34-40 °C）的 pH 和温度变化没有影响，共同表明这种复合生物传感器在用于神经化学监测时应该可靠地检测l-谷氨酸。涉及在自由活动大鼠纹状体中植入的初步实验证明了数周内的稳定记录，并可靠地检测到谷氨酸响应行为/神经元激活（运动活动和约束压力）的生理变化。