IMPROVED SEPARATION MEDIA FOR ELECTROPHORESIS

在通过电泳进行的DNA测序分析中， 中可以使用进一步的改进。 的长期目标 建议的项目是开发一种更好的分离介质， 克服了与目前聚丙烯酰胺相关的许多问题 溶液或凝胶：聚合物溶液通常太粘而不能填充 毛细管;原位聚合方法并非如此 可再现;聚合物凝胶的保存期有限。中心主题是 为了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 嵌段的化学性质、总链长、嵌段长度 选择性溶剂中嵌段的比例和分子结构 其是用于DNA测序分析的缓冲溶液。 在 自组装聚合物网络，预计几个理想的 可以将这些性质设计到分离介质的性质中。 例如，（1）在操作温度范围之外的温度下 对于电泳，低分子量嵌段共聚物（例如， 普朗尼克多元醇）溶液具有低粘度，便于填充 毛细管或薄板，和（2）在操作温度下， 电泳，自组装的超分子可以形成凝胶， 适合于DNA测序分析的预定结构。 为了给设计更好的分离介质提供依据， 这些缠结的聚合物链（或凝胶）的结构将被研究 通过物理技术，例如粘度测定法、流变测定法、激光 光散射，小角中子散射，小角X射线 散射，C13和质子NMR，并与电泳相关 结果 通过使用相同的物理技术，建议研究 多分散性对聚合物链缠结的影响以及混合 聚合物（例如聚丙烯酰胺）溶液/琼脂糖凝胶方法， 用于检查是否可以获得更大的网眼尺寸的聚合物网络 以分辨更大的DNA片段。琼脂糖凝胶用于 限制聚丙烯酰胺链的平移运动， 控制分离介质和聚合物链的粘度 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.