| Summary: | 碩士 === 國立中正大學 === 化學研究所 === 91 === Abstract:
We have performed single molecule fluorescence detection of DiI molecules in PMMA films, where the surrounding air composition was controlled by nitrogen flushing. The change of the triplet state lifetime of individual dye molecules with and without nitrogen purging was monitored by means of the time resolved single photon counting system. From the fluorescence burst trajectories and the statistic histograms, we could estimate the triplet state lifetime of 51.8ms under nitrogen flushing. We found the experimental results similar to the literature. It proved that our home-made instruments had the ability to detect single molecules.
We have applied fluorescence correlation spectroscopy (FCS) and fluorescence image to determine the lateral diffusion coefficients of lipid molecules in artificial membranes on the level of individual molecules. Two methods yielded the diffusion constants of 2.35 μm2s-1 and 2.75 μm2s-1, respectively. We also applied the anomalous diffusion model to the data analysis. The result indicated that the artificial membrane made of egg-PC is homogenous distribution, no anomalous diffusion.
In addition to the study of the lipid diffusion motion, we set to investigate the mechanism of the aggregation of cobra cardiotoxin on biomenbrane. Up to now, we have prepared giant unilamellar vesicles with different kind of compositions, and this project is in progress.
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