Selenide-based electrocatalytic sensors for sensitive peroxynitrite detection in biological media: a bottom-up approach for functional interface design

项目总结： 背景与挑战：过氧亚硝酸根(Oono-)是一种有效的细胞毒性化合物。 牵涉到一系列的病理生理状况。过氧亚硝酸盐是亚硝酸盐的主要产品 体内一氧化氮和超氧阴离子自由基的反应。它的多方面生理反应 化合物直接与许多病理有关，包括心血管疾病、免疫 反应、慢性炎症和败血症，仅举几例。根据美国《每日邮报》最近的统计数据 心脏协会，仅心血管疾病就声称每4分钟就有7人死亡。另一方面 另一方面，败血症每年影响美国170万成年人，并可能导致更多 超过25万人死亡。仅这两项统计数据就令人震惊，并使这一致命的足迹 生物分析物是一个重要的优先事项。将过氧亚硝酸盐与所有引用的病理联系起来的共同线索 它对细胞中的大多数细胞成分包括dna、蛋白质和脂类都有很强的反应性。 膜。蛋白质、DNA和脂质的大量氧化和其他转化有助于 关键细胞功能的中断。 评估过氧亚硝酸盐的有害作用并检验其潜在信号作用的假说 如果不首先准确测量和监测其浓度，就不可能实现这一目标。这项任务是 然而，由于生理条件下亚微摩尔浓度低，固有的困难 具有很高的反应性。对过氧亚硝酸根的灵敏和准确的测量是揭示真相的关键 关于这种代谢物的虚幻的病理生理作用。一些已知的检测方法可用于 过氧亚硝酸盐包括荧光探针的氧化、EPR光谱、化学发光、 免疫组织化学和探针硝化；然而，这些更难应用于实时 量化由于其固有的复杂性。过氧亚硝酸根的电化学检测更简单 和更方便的技术应用于生物环境。然而，一个系统的发展 缺乏能够提高该分子的灵敏度和选择性的右电极界面。 近年来，合成的有机硒化合物已被合成作为药物化学中的抗氧化剂。 我们手中的电化学数据显示，一些有机硒化合物具有特定的氧化还原能力 溶液中过亚硝酸根的活性。出于这些原因，我们认为一个电极界面装饰 表面附着的有机硒化合物将有可能作为介导性PON的催化实体 电催化测定。 我们的建议：在这项工作中，我们建议开发一种功能薄膜材料，基于定义的 有机硒化合物化学附着在石墨电极上，并使用该界面在敏感 过氧亚硝酸根的电化学测定。这种自下而上的界面设计方法是创新的 因为它允许我们设计一个电催化界面来检测和确定 过亚硝酸根是由所用有机硒化合物的分子和电子性质驱动的。这是由以下因素推动的 富含氧化还原的有机硒化合物将允许我们将它们用作活性物质的总体假设 氧化还原催化中心固定在电极表面，用于电催化测定溶液中的PON。 这项工作将追求三个具体目标：1)研制一种无源光网络的硒修饰电极 使用参考化合物进行测定，然后2)生成具有不同变化的硒的文库 在硒催化中心上的取代基，并测试所得到的改性产物的催化性能 用于PON测定的接口；以及最后3)使性能最好的催化接口小型化 通过将工艺转移到超微电极(碳纤维)来制备单体PON 在生物环境下使用的微型传感器。意义：成功开发出一款可靠的 PON微型传感器不仅可以实现对生物压力下的这种反应性应激标记的原位测量 但也将揭示这种强大的物种在 许多疾病状态。

Project Summary: Background and Challenge: Peroxynitrite (OONO-) emerged as a potent cytotoxic compound and has been implicated in a host of pathophysiological conditions. Peroxynitrite is the primary product of the in vivo reaction of nitric oxide and superoxide anion-radical. The multifaceted physiologic reactions of this compound are directly implicated in a number of pathologies including cardiovascular disease, immune response, chronic inflammation, and sepsis, to cite a few. According to recent statistics by the American Heart Association, just cardiovascular disease alone claims about 7 deaths every 4 minutes. On the other hand, sepsis affects 1.7 million adults in the United States each year and potentially contributes to more than 250,000 deaths. Just these two statistics are staggering and make the footprint of this deadly biological analyte an important priority. The common thread that links peroxynitrite to all cited pathologies is its potent reactivity toward most cellular components including DNA, proteins, and lipids in cell membranes. Substantial oxidations and other transformations of proteins, DNA, and lipids contribute to the disruption of key cellular functions. Assessing peroxynitrite’s deleterious effects and examining hypotheses of its potential signaling roles cannot be achieved without first accurately measuring and monitoring its concentration. This task is however inherently difficult due to low submicromolar concentrations under physiologic conditions coupled with its high reactivity. Sensitive and accurate measurement of peroxynitrite is crucial in order to shed light on the illusive pathophysiologic roles of this metabolite. Some of the known detection methods for peroxynitrite include oxidation of fluorescent probes, EPR spectroscopy, chemiluminescence, immunohistochemistry, and probe nitration; however, these are more difficult to apply for real-time quantification due to their inherent complexity. The electrochemical detection of peroxynitrite is a simpler and more convenient technique for application in biological settings. However, a systematic development of the right electrode interface that enhances the sensitivity and selectivity for this molecule is lacking. Recently, several synthetic organic selenides have been prepared as antioxidants in medicinal chemistry. Electrochemical data in our hands showed that some organoselenium compounds have specific redox activity with peroxynitrite in solution. For these reasons, we believe that an electrode interface decorated with organoselenides attached to the surface will potentially serve as catalytic entities for mediated PON electrocatalytic determination. Our proposal: In this work, we propose to develop a functional thin film material based on defined organic selenides chemically attached on graphite electrodes and use this interface in sensitive electrochemical determination of peroxynitrite. This bottom-up interface design approach is innovative because it allows us to design an electrocatalytic interface for the detection and determination of peroxynitrite driven by molecular and electronic properties of the organic selenides used. This is driven by the overall hypothesis that the redox-rich organoselenium compounds will allow us to use them as active redox catalytic centers tethered to the electrode surface to electrocatalytically measure PON in solution. The work will pursue three specific aims including: 1) developing a selenide-decorated electrode for PON determination using a reference compound, followed by 2) generating a library of selenides with varying substituents on the selenium catalytic center and test the catalytic properties of the resulting modified interface towards PON determination; and finally 3) miniaturizing the best performing catalytic interfaces by transferring the process to ultramicroelectrodes (carbon fiber) to prepare a single-body PON microsensor for use under biological settings. Significance: The successful development of a reliable PON microsensor will not only enable in-situ measurement of this reactive stress marker under biological setting but will also shed light on obscure mechanisms through which this potent species operates under many disease states.