Enhanced EPR Sensitivity for Biomedical Research

描述（由申请人提供）：我们的长期目标是实现生物医学EPR测量灵敏度的显着提高。该方法是设计用于标准商用腔谐振器的介电插入。我们的假设是，由适当的材料和适当的尺寸制成的插入物可以重新分配腔内的微波场，从而大大增加样品上的填充系数和微波磁场强度，从而将EPR灵敏度提高一个数量级。这个试点项目的主要重点是设计电介质插入，以提高对肌肉研究的特定应用的灵敏度。鉴于EPR在生物医学研究中的快速发展，特别是在定点自旋标记和高频EPR方面，提出的发展将对现代生物医学EPR测量产生直接影响。该建议是先前工作的逻辑延伸，该工作已经证明，通过在标准EPR腔中插入铁电KTaO3，可以显著提高自旋标记肌肉纤维EPR测量的灵敏度。本研究的四个主要目标是：(1)建立包含介电插入体的EPR腔谐振频率和微波场分布的计算方法，并制造设计的介电插入体。(2)针对肌肉研究中重要的特定应用修改目标1中的设计：样品方向与外部磁场平行。(3)进行控制测量以评价插入物的物理性能。(4)测量生物样品信号强度的提高，特别是对自旋标记的肌肉蛋白和肌肉纤维。这个试点项目将强调开发可靠的计算方法来设计增强灵敏度的植入物，并通过实验证明这些方法适用于典型的肌肉研究应用。这将为未来生物医学EPR研究灵敏度增强的系统发展奠定基础，将EPR的高分辨率能力引入到复杂分子结构和动力学的分析中，以解决许多以前无法解决的生物医学问题。

DESCRIPTION (provided by applicant): Our long-term goal is to achieve a dramatic improvement in the sensitivity of biomedical EPR measurements. The approach is to design dielectric inserts to be used with standard commercial cavity resonators. Our hypothesis is that an insert made of appropriate materials and having appropriate dimensions can redistribute the microwave field within a cavity in a way that substantially increases the filling factor and microwave magnetic field intensity uniformly over the sample, increasing EPR sensitivity by as much as an order of magnitude. The primary emphasis of this pilot project is to design dielectric inserts that enhance sensitivity in specific applications to muscle research. Given the rapid growth of EPR in biomedical research, especially in site-directed spin labeling and high-frequency EPR, the proposed developments will have immediate impact on modem biomedical EPR measurements. This proposal is a logical extension of previous work that has demonstrated the remarkable enhancement of sensitivity of EPR measurements of spin labeled muscle fibers by ferroelectric KTaO3 insert in standard EPR cavities. Four specific aims will be addressed: (1) Develop methods for calculating the resonant frequency and microwave field distribution of an EPR cavity containing a dielectric insert, and manufacture the designed insert. (2) Modify the designs in Aim 1 for specific application important for muscle research: sample orientation parallel to the external magnetic field. (3) Perform control measurements to evaluate the physical performance of the insert. (4) Measure the improvement of signal intensity for biological samples, especially for spin-labeled muscle proteins and muscle fibers. This pilot project will emphasize the development of reliable computational methods for designing sensitivity-enhancing inserts and to demonstrate experimentally that these methods work for typical muscle research applications. This will lay the foundation for future systematic development of sensitivity enhancements for biomedical EPR research, bringing the high resolution capabilities of EPR to the analysis of complex molecular structure and dynamics in a wide range of previously inaccessible biomedical problems.