共振腔微擾法量測奈米磁流體磁導率探討

Abstract

共振腔微擾法是一種量測物質介電常數及磁導率的量測方法。共振腔微擾法使用網路分析儀量測一電磁波空振腔體在放入代測物後所產生之共振頻率偏移與腔體內品質因數Q 值變化，由此推算代測物之介電常數及磁導率。共振腔微擾法有非常好的精確度以及只需要極少量樣品的優點。 Fe3O4奈米磁流體近年來廣泛運用在生醫領域中，生醫檢測更是其中著重發展的目標之一。本研究以量測Fe3O4結合分子後的磁導率變化，探討以共振腔微擾法作生醫檢測應用之可行性。 本研究使用共振腔微擾法量測四氧化三鐵Fe3O4奈米磁流體以及Fe3O4結合PEG或FITC-NHS ester分子後之磁流體溶液在2Ghz~5Ghz之高頻交變磁場下之磁導率。本研究使用一長方體共振腔，量測所用的電磁波模態為TE102與TE104。實驗所用的Fe3O4奈米磁顆粒是以化學沉積法製作，磁顆粒樣品平均粒徑大小約為25nm，表面zeta電位約為+50mv。

Cavity resonator perturbation technique is a technique for measuring the complex permeability and dielectric constant of materials. This method uses network analyzer to measure the shift of resonant frequency and the change of quality factor in a resonant cavity. These performance changes of cavity can be used to derive the complex permeability and dielectric constant. Cavity resonator perturbation technique has very good accuracy and only needs small volume of measured samples. The Fe3O4 ferrofluids have been widely used for biomedical applications recent years, and the biomedical detection is one of the significant application of it. This study would like to provide a possibility of application on biomedical detection by using cavity resonator perturbation technique. This study use cavity resonator perturbation technique to measure the complex permeability of three different samples: The pure Fe3O4 ferrofluids and Fe3O4 ferrofluids coated by PEG or FITC-NHS ester. The measurement frequency is at 2GHz to 5Ghz. The used cavity is a rectangular cavity resonator and the dominant mode of the measurement is TE102 and TE104. The Fe3O4 nanoparticles sample is prepared by chemical disposition method, its average particle size is 25nm, and the zeta potential is 50mv.