IMPROVED SEPARATION MEDIA FOR ELECTROPHORESIS

在用电泳法进行DNA测序分析中，分离 Medium可以做进一步的改进。该计划的长远目标 建议的项目是开发一种更好的分离介质，它可以 克服与目前的聚丙烯酰胺有关的许多问题 溶液或凝胶：聚合物溶液通常太粘稠，无法填充 毛细管；原位聚合方法不是这样 可重复性；聚合物凝胶的保质期有限。中心主题是 要利用嵌段共聚物的自组装行为 预先设计的聚合物网络可以通过考虑 区块的化学性质、总链长、区块长度 选择性溶剂中嵌段的比例和分子结构 这是DNA测序分析中使用的缓冲液。在 自组装的聚合物网络，预计会有几种可取的 性质可以设计成分离介质的性质。 例如，(1)在工作温度范围之外的温度 对于电泳法，低分子量嵌段共聚物(例如 Pluronic多元醇)溶液粘度低，易于填充 毛细管或薄板，以及(2)在使用温度下 电泳法，自组装的超分子可以形成凝胶 适合DNA测序分析的预定结构。 为了为设计更好的分离介质提供依据， 我们将研究这些缠绕在一起的聚合物链(或凝胶)的结构。 借助物理技术，如粘度计、流变仪、激光 光散射、小角中子散射、小角x射线 散射、C_(13)和质子核磁共振，并与电泳法相关 结果。 通过使用相同的物理技术，建议研究这些影响 多分散性对聚合物链缠结的影响及混合分子的使用 聚合物(如聚丙烯酰胺)溶液/琼脂糖凝胶方法 用于检查是否可以实现更大网目尺寸的聚合物网络 以解析更大尺寸的DNA片段。琼脂糖凝胶用于 限制聚丙烯酰胺链的平移运动，以便 控制分离介质和高分子链的粘度 动力学。

In DNA sequencing analysis by means of electrophoresis, the separation medium could use further improvements. The long-term objective of the proposed project is to develop a better separation medium which can overcome many of the problems related to the present-day polyacrylamide solutions or gels: polymer solutions are often too viscous to be filled in capillary tubings; the polymerization in situ approach is not so reproducible; shelf-life for polymer gels is limited. The central theme is to take advantage of the self-assembly behavior of block copolymers so that predesigned polymer networks can be formulated by considering the chemical nature of the blocks, the total chain length, the block length ratio and the molecular architecture of the blocks in a selective solvent which is the buffer solution used in DNA sequencing analysis. In the self-assembled polymer networks, it is expected that several desirable properties can be designed into the properties of the separation medium. For examples, (1) at temperatures outside the operating temperature range for electrophoresis, the low molecular weight block copolymer (e.g. Pluronic polyols) solution has a low viscosity for ease of filling in capillary tubings or thin slabs, and (2) at the operating temperatures for electrophoresis, the self-assembled supramolecules can form gels of predetermined structures suitable for DNA sequencing analysis. In order to provide a basis for the design of a better separation medium, the structures of these entangled polymer chains (or gels) will be studied by means of physical techniques, such as viscosimetry, rheometry, laser light scattering, small angle neutron scattering, small angle x-ray scattering, C13 and proton NMR, and be correlated with electrophoresis results. By using the same physical techniques, it is proposed to study the effects of polydispersity on polymer chain entanglements and the use of a mixed polymer (e.g. polyacrylamide) solution/agarose gel approach which will be used to examine whether larger mesh size polymer networks can be achieved in order to resolve larger size DNA fragments. The agarose gel is used to restrict the translational motions of polyacrylamide chains so as to control the viscosity of the separation medium and the polymer chain dynamics.