生化学分析のための二次元及び三次元の画像分析とキャピラリー電気泳動
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概要
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The first three-dimensional (3-D) description of DNA electrophoretic migration is reported. The assumption of uniform probability of out-of-plane orientations, frequently made for DNA migration theory, has been verified. Also DNA gyration was clearly observed between the J forms and the original ball forms. The use of apparent two-dimensional (2-D) opening angles underestimated the true behavior. An extension of the Oana/Doi ellipsoidal approximation to DNA dimensions was used for quantitative descriptions. Although several limitations of the 3-D ellipsoid approximation are pointed out, it is sufficient for DNA migration image analysis. Statistics of DNA single molecule dynamics in DC electrophoresis systems were used to predict the ensemble electrophoretic migration times and overall band shapes. The migration times were predicted adequately and the asymmetric band shapes observed in electrophoresis were mirrored in the asymmetric migration time distributions of single molecules. Because the proper scaling relation is not known, it has not been possible to establish whether or not the data accurately predicts the bandwidth from single DNA molecule dynamics. Similar successes and limitations were observed for field inversion electrophoresis. Sample-size studies show that the range of the possibilities for DNA motions is limited, and much of it is explored rapidly. Scanning electron microscopy (SEM) and extended focus (EF) light microscopy were used for acquiring surface images of electrochemical surface enhanced Raman spectroscopy (SERS) substrates. Self-similarity was found from 30μm to 100nm, and was used to define the optimum fractal dimension for SERS activity, approximately 1.7. The activity thresholds found by both SEM and EF light microscopy were similar. Therefore, EF microscopy can be used to assess the quality of an electrode surface before it is irrevocably committed to an experiment.
- 社団法人日本分析化学会の論文
- 2005-07-05