Electrostatics and dielectric properties of bio-nano interface by spin-labeling EPR

化学系的化学测量和成像项目将资助北卡罗莱纳州立大学的Tatyana Smirnova教授开发新的电子顺磁共振（EPR）光谱技术，用于评估脂质纳米结构混合材料的局部静电和介电性能。本课题的研究重点是设计新的光谱探针和开发实验方法，以研究纳米结构的支持和约束对生物膜和膜-蛋白界面性能的影响。该研究项目是在高度跨学科的环境中培养来自不同背景的研究生和本科生的工具。通过设计一套基于EPR光谱学研究和工业应用的本科教学实验室，将研究活动与教育相结合。拟议的基于应用程序的EPR实验室练习套件旨在改善STEM教育，并提供适合当今科学和技术劳动力的技能。新的ph敏感的EPR活性探针和标签正在合成，使质子浓度和局部介电常数在非均质纳米级系统的测量。新方法被应用于描述磷脂膜和膜-蛋白界面的局部介电常数和质子梯度。脂质膜的纳米限制在多大程度上可以改变磷脂双分子层和蛋白质-脂质界面内的极性、水和质子谱，并可能破坏脂质-蛋白质和蛋白质-蛋白质相互作用的最佳条件，目前正在研究中。该方法有望广泛应用于一系列新型脂质-纳米结构混合体，有望开辟新的分析和技术应用。

With this award, the Chemical Measurement and Imaging Program of the Division of Chemistry is funding Professor Tatyana Smirnova of the North Carolina State University to develop new Electron Paramagnetic Resonance (EPR) spectroscopy techniques for assessing the local electrostatics and dielectric properties of lipid-nano-structured hybrid materials. This research project focuses on designing new spectroscopic probes and developing experimental methods to investigate the influence of nanostructured support and confinement on properties of biological membranes and the membrane-protein interface. The research project is a vehicle for the training of graduate and undergraduate students from diverse backgrounds in highly interdisciplinary environment. Research activities are being integrated with education through designing of a suite of undergraduate teaching labs based on research and industrial applications of EPR spectroscopy. The proposed application-based suite of EPR laboratory exercises aims to improve STEM education and provide skills appropriate for the present day science and technology workforce.New pH-sensitive EPR active probes and labels are being synthesized to enable measurements of proton concentration and local dielectric constant in heterogeneous nanoscale systems. The new methodology is being applied to profile local dielectric constant and proton gradients in phospholipid membranes and along membrane-protein interface. The extent to which nano-confinement of lipid membranes can alter the polarity, water and proton profiles within the phospholipid bilayer and at the protein-lipid interface and potentially disrupt the optimal conditions for the lipid-protein and protein-protein interactions is being investigated. The methodology being developed is expected to be widely applicable to an array of novel lipid-nanostructure hybrids that hold promise to open new analytical and technological applications.