| Summary: | 碩士 === 國立中正大學 === 化學研究所 === 92 === In order to expand the diversity of the techniques of detecting single molecules, we experiment on the practicability of 633 nm He-Ne laser for single molecule excitation, in addition to 532 nm light. From the single molecule wide field images of the dye Alexa Flour 647, we get the intensity of the signal close to that excited by 532nm. The low noise level is advantageous for the future experiments on the single molecule detections of living cells. In the nitrogen effect experiment, fluorescence intensity shows little variation under either nitrogen or oxygen, which differs from the result of DiI excited by 532nm. We also conduct fluorescence polarization detection. Fluorescence from a dye molecule is resolved into parallel and perpendicular polarization components and separately detected. We consequently acquire the orientation of the dye molecules in solid matrix.
As a result of moving at high diffusion rate in agarose hydrogels, we cannot measure diffusion rate by single molecule tracking technique. Therefore we investigate diffusion processes, using the technique of fluorescence correlation spectroscopy, FCS. We conclude that the motion of dye molecules and protein molecules are described best by including anomalous diffusion and adsorption. We have obtained the ratio of anomalous diffusion and adsorption under various circumstances. We have also investigated the flowing dynamics of molecules under electric field.
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