| Summary: | 碩士 === 國立東華大學 === 應用物理研究所 === 95 === In this study we used low-resistivity indium tin oxide (ITO) substrate to obtain high resolution scanning electron microscopy (SEM) images of biological samples without any conductive coating. First, the macrophages of raw264.7 cells were immobilized on the ITO substrate and then observed by a field-emission scanning electron microscope (FESEM) at various accelerating voltages. The effect of accelerating voltage on the image resolutions of secondary electron (SE) and backscattering electron (BE) images is significantly large. For example, the morphologies of the macrophages in the BE images is corresponding to their atomic number contrasts at various accelerating voltages. Also, the macrophages of raw264.7 cells immobilized on glass substrates were examined by the FESEM at various accelerating voltages. The results of the macrophages on the glass substrate compared with those of the macrophages on the ITO substrate are much worse.
Secondly, the macrophages were immobilized on substrates with varying resistivity to understand the effect of resistivity on the image resolution of SEM images. We found that the low-resistivity substrate helping acquire high resolution FESEM images for macrophages is much better than not only the insulating glass substrate, but also the good conductive copper substrates. This method confirms that the low-resistivity ITO substrate can supply high resolution for morphology of biological samples in SEM images without any conductive coating. Therefore, details of biological morphology are not obscured or distorted by conductive coating.
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