Development and Application of L-band ESR system for in vivo analysis

本研究新开发的l波段ESR系统使生物样品的体内测量成为可能。带电屏蔽环隙谐振器制作了带电屏蔽环隙谐振器（谐振频率为0.7 ~ 1ghz），并通过插入盐水溶液检测了该谐振器的特性。结果表明，电屏蔽对大量湿样的测量是有效的。通过计算机与l波段ESR光谱仪连接，实现了磁场扫描、ESR信号处理和谐振频率自动控制。信号的积累和平滑使灵敏度提高了约10倍。频率自动控制可获得较好的ESR谱，且无基线波动。应用于生物样品和材料样品的测定新鲜芹菜和大鼠体内外源性氮氧自由基的行为。观察了通过芹菜茎的自由基含量的变化和叶片中的腐烂行为。对大鼠头部注射的一氧化氮自由基进行了动态研究。此外，对锰干电池进行了原位测量，结果表明阴极混合物中碳自由基的含量与干电池的放电反应密切相关。为了得到样品中自由基的分布情况，采用层析法对不同样品进行了二维ESR成像。

L-band ESR system which makes it possible to perform in vivo measurements of biological samples has been newly developed in this study.1. Loop-gap resonator having an electric shieldLoop-gap resonator (resonant frequency = 0.7 to 1 GHz) having an electric shield in the loop was made, the characteristics of this resonator were examined by insertion of saline salt solution. The results indicated that electric shield was effective to measurements of wet samples of large quantities.2. On-line system by computerBy connecting computer to L-band ESR spectrometer, scanning of magnetic field, proccessing of ESR signals, and auto control of resonant frequency were carried out. Accumulation and smoothing of signals increased the sensitivity by about 10 times. Auto controller of frequency could afford good ESR spectra without fluctuation of baseline.3. Application to measurements of biological and material samplesBehaviors of exogenous nitroxide radicals in fresh celery and rat could be examined at in vivo state. The change of radical content passing through celery stalk and the decay behavior in the leaves were observed. Attempts of dynamic studies of nitroxide radicals injected in rat were made at the head of rat. Furthermore, in situ measurements of manganese dry cell were performed, and the results suggested that the carbon radical contained in cathode mix was strongly related to the discharge reactions of dry cell.4. ESR imagingIn order to get the distribution of radicals in sample, two-dimensional ESR imaging of various samples was carried out by Zeugmatography.