DEVELOPMENT OF SELF REFERENCING ELECTROCHEMICAL MICROSENSORS ASCORBIC ACID

使用氧气和一氧化氮测量的经验 自参考探针，特别是构建我们的能力 自己的碳基微传感器为分子生物学开辟了新的视野 通量检测。 抗坏血酸检测方法的探索 Harold Behrman（B00. of Obs. and Gyn. Yale Medical 的请求） 学校）。 抗坏血酸具有令人好奇的品质 明显的细胞外通量模式，缓慢振荡 延长的时间段。 这在哺乳动物中尤其明显 CNS，其中 AA 电化学信号需要被过滤掉 儿茶酚胺检测。 我们在这个子项目中的目的是 探索我们产生自参考系统的能力 测量单细胞通量，从而有助于我们理解 潜在的 AA 运输生理学。 这些探针建立在 用于构建的基本碳纤维电极 一氧化氮探针并经过电化学修饰以改善 对抗坏血酸的敏感性。 此次准备工作涉及 碳纤维的电化学处理（1.5V 3 秒；70 Hz 3V 1.5V 偏置三角波 10 秒；然后保持在 0V 30 分钟）。 这会导致工作潜力下降 将AA从0.9V氧化至0.05V所需。 电极是 在已知 AA 浓度的溶液中校准（线性 校准）。 虽然这些微探针的操作 自参考模式已使用人工梯度得到验证， 我们还没有将它们应用到生物系统中。 续 自参考电化学微传感器的发展 通过三种方法发生。 其中包括开发新的 传感器、循环伏安法和计时电流法的应用， 但最快的方法是调整现有的 用于单电池的电化学探针。 后面的例子 方法是新的自参考抗坏血酸探针，其 与从氧气转向一氧化氮相比，发展迅速且简单。 我们 预计能够为生物医学研究人员提供一个“菜单” 他们在设计实验时可以选择的探针。

Experience with both oxygen and nitric oxide measurement using self-referencing probes, and, in particular, the ability to build our own carbon based microsensors has opened up new horizons for molecular flux detection. The detection of ascorbic acid was explored on the request of Harold Behrman (B00. of Obs. and Gyn. Yale Medical School). Ascorbic acid has the curious quality of exhibiting pronounced extracellular flux patterns, with slow oscillations over extended time periods. This is particularly evident in the mammalian CNS where AA electrochemical signals need to be filtered out for catecholamine detection. Our intention in this sub-project was to explore our ability to produce a self-referencing system able to measure single cell flux and thus contribute to our understanding of the underlying AA transport physiology. These probes are built upon the basic carbon fiber electrode used for the construction of the nitric oxide probes and are modified electrochemically to improve sensitivity for ascorbic acid. This preparation involved the electrochemical treatment of a carbon fiber (1.5V for 3 sec; 70 Hz 3V triangle wave with 1.5V offset for 10 sec; followed by a hold at 0V for 30 minutes). This results in a decrease in the working potential required to oxidize AA from 0.9V to 0.05V. The electrodes are calibrated in solutions of known AA concentrations (linear calibration). While the operation of these microprobes in the self-referencing mode has been verified using an artificial gradient, we have not yet applied them to a biological system. Continued development of the self-referencing electrochemical microsensors can occur through three approaches. These include the development of new sensors, the application of cyclic voltammetry and chronoamperometry, but the most rapid approach is the adaptation of existing electrochemical probes for single cell use. An example of the later approach is the new self-referencing ascorbic acid probe whose development was rapid and simpler than moving from oxygen to NO. We anticipate being in a position to over biomedical researchers a "menu" of probes from which they can choose in designing their experiments.