Enhanced EPR Sensitivity for Biomedical Research

增强生物医学研究的 EPR 敏感性

• 批准号: 6675191
• 负责人: YURI NESMELOV
• 金额: $ 7.16万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6675191
• 关键词: bioengineering /biomedical engineering; biomedical equipment development; biophysics; dielectric property; electron spin resonance spectroscopy; magnetic field; mathematics; method development; microwave radiation; muscle

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.

描述(由申请人提供)：我们的长期目标是实现生物医学EPR测量灵敏度的显著提高。方法是设计与标准商用腔谐振器一起使用的介电插件。我们的假设是，由合适的材料和合适的尺寸制成的插件可以在腔内重新分布微波场，从而显著增加填充因子和样品上的微波磁场强度，使EPR灵敏度增加多达一个数量级。该试验项目的主要重点是设计可提高肌肉研究特定应用的灵敏度的介电插件。鉴于EPR在生物医学研究中的快速增长，特别是在定点自旋标记和高频EPR方面，拟议的发展将对现代生物医学EPR测量产生直接影响。这一建议是先前工作的合乎逻辑的扩展，该工作证明了在标准EPR腔中插入铁电KTaO_3可以显著提高自旋标记肌肉纤维的EPR测量的灵敏度。具体目标有四个：(1)建立含介质插入件的EPR腔的谐振频率和微波场分布的计算方法，并制作所设计的插入件。(2)修改目标1中的设计，以适应对肌肉研究很重要的特定应用：平行于外部磁场的样品取向。(3)进行控制测量，以评估镶件的物理性能。(4)测量生物样品，特别是自旋标记的肌肉蛋白和肌肉纤维的信号强度的改善。这个试点项目将强调开发可靠的计算方法来设计提高敏感性的插入物，并通过实验证明这些方法适用于典型的肌肉研究应用。这将为未来系统地开发生物医学EPR研究的灵敏度增强奠定基础，将EPR的高分辨率能力带入分析一系列以前无法解决的生物医学问题的复杂分子结构和动力学。