Sensory Lipid Membrane Films with Integrated Inorganic Coordination Complexes

纯水中阴离子的检测和识别是当前超分子化学中的一个重大挑战，至今仍是一个相对未发展的研究领域。这是由于与感应阴离子相关的根本挑战，归因于它们与周围水分子(高溶剂化能)的强烈联系，需要打破这些分子才能与受体结合。这些受体在水中的溶解度较低，对目标阴离子的选择性较差，结合部位的阴离子亲和力较弱而加剧了这一问题。无机磷作为化学构件普遍存在于生物系统中，例如存在于大多数代谢反应中。它还与环境高度相关，农业中化肥使用量的增加导致了水道中磷酸盐的过量。这导致了富营养化，其影响可以在有害的藻类水华和水生生物的低氧“死区”中看到。常用的检测磷酸盐水平的技术从使用传统的分子荧光探针和光学分析到核磁共振滴定技术，应有尽有。然而，这些基于实验室的方法通常昂贵、耗时和费力。相比之下，电化学传感器携带方便，价格低廉，可用于现场连续监测。可以有效地设计受体与阴离子的结合环境，以促进受体与靶向阴离子之间的高亲和力或强结合。感官膜表现出可测量的结合增强因子，其中溶剂化效应受到控制。控制这种效应的一种实用方法是使用这样的薄膜，这些薄膜提供了调节界面介电微环境的能力，从而减少了电荷屏蔽，从而增强了带电阴离子与结合位置之间的相互作用。在这个项目中，我们将开发人工疏水类脂双层，这是这种有机感觉膜的一个例子，因此阴离子结合基序可以很容易地整合到这些双层中。这些膜将固定在电极表面，以获得电化学传感器。电化学电容测量将在电极和薄膜之间的交界处通过施加固定电压和使用低幅度交流电而改变频率来进行。这些电容测量将有效地探测薄膜存储电荷的能力，即磷酸盐与电极表面膜锚定受体的结合事件的频率和强度，并因此量化磷酸盐水平。该项目属于EPSRC电化学科学、传感器和仪器、合成配位化学、合成超分子化学研究领域的物理科学研究主题。

Anion detection and recognition in pure water is a significant current challenge in supramolecular chemistry, to this day remains relatively unevolved as a research field. This is due to the fundamental challenges associated with sensing anions, attributed to their strong association with surrounding water molecules (high solvation energies) that needs to be broken in order to bind to a receptor. These receptors often have low solubility in water and poor selectivity for the target anion, exacerbated by weak anion affinity to the binding site.Inorganic phosphate is ubiquitous as a chemical building block in biological systems, for example being present in the majority of metabolic reactions. It is also highly environmentally relevant, whereby the rising use of fertilisers in agriculture has led to an overabundance of phosphates in waterways. This results in eutrophication, the effects of which can be seen in harmful algal blooms and hypoxic 'dead zones' of aquatic life. Common techniques of detecting phosphate levels vary from the use of traditional molecular fluorescence probes and optical analysis to NMR titration techniques. However, these lab-based methods are typically expensive, time consuming and laborious. Electrochemical sensors, in contrast, are portable, cheap and can be used in the field for continuous monitoring.The binding environment of a receptor for anions can be effectively engineered to promote high affinity, or strong binding, between the receptor and targeting anion. Sensory films exhibit measurable binding enhancement factors, where solvation effects are controlled. A practical way of controlling such effects is by using such films which afford the ability to tune the interfacial dielectric microenvironment, such that there is reduced charge screening, and hence stronger interactions between the charged anion and binding site. In this project we will develop artificial hydrophobic lipid bilayers, which are an example of such organic sensory films, whereby anion binding motifs can be readily integrated into these bilayers. These membranes will be immobilised on an electrode surface in order to obtain an electrochemical sensor. Electrochemical capacitance measurements will be taken at the interface between the electrode and the film by applying a fixed voltage and varying frequency using a low magnitude alternating current. These capacitance measurements will effectively probe the ability of the film is able to store charge, i.e. the frequency and strength of binding events of phosphate to the membrane anchored receptors at the electrode surface, and as such, quantify phosphate levels.This project falls in the EPSRC electrochemical sciences, sensors and instrumentation, synthetic coordination chemistry, synthetic supramolecular chemistry research areas within the physical sciences research theme.