中文摘要：

DNA凝聚在非病毒基因传递中起关键作用,而基因治疗则是基因传递的一个重要应用,所以DNA凝聚的研究对于基因治疗具有一定的意义。而溶剂介电常数的改变对DNA凝聚具有一定影响,所以本文作者通过动态光散射和单分子磁镊技术研究溶剂介电常数的改变对三氯六氨络合钴导致的DNA电泳迁移率变化和凝聚力的影响。动态光散射实验结果显示,DNA的电泳迁移率随着三氯六氨络合钴浓度的增加而增加;在一定三氯六氨络合钴浓度下,增大溶剂的介电常数,DNA的电泳迁移率变小,减小溶剂的介电常数,则DNA的电泳迁移率变大。同时作者用单分子磁镊实验定量研究不同介电常数对三氯六氨络合钴导致DNA凝聚力变化的影响,发现介电常数的减小会使DNA的凝聚力变大,反之,则DNA的临界凝聚力变小。可见,溶剂的介电常数可以改变三氯六氨络合钴与DNA凝聚复合物的带电量及凝聚力。

英文摘要：

DNA condensation plays a key role in gene delivery,and gene therapy is an important application of gene delivery, so the study of DNA condensation has a certain significance for gene therapy. The change of dielectric constant in solvent has certain influence on DNA condensation. Therefore, we studied the effect of solvent dielectric constant on the DNA electrophoretic mobility and critical condensing force induced by hexamine cobalt （Ⅲ） using dynamic light scattering and single molecular magnetic tweezers. The results of dynamic light scattering experiments showed that the electrophoretic mobility of DNA increased with the increase of concentration of hexamine cobalt （Ⅲ）. If the concentration of hexamine cobalt （Ⅲ） did not change, the electrophoretic mobility of DNA increased with the decrease of dielectric constant of the solvent. If the dielectric constant of the solvent was increased, the electrophoretic mobility of DNA decreased. In the meanwhile, we studied the effect of solvent dielectric constant on the DNA condensing force induced by hexamine cobalt （Ⅲ） using single molecular magnetic tweezers. The results showed that the critical condensing increased with the decrease of dielectric constant. On the contrary, the critical condensing force of DNA decreased. In conclusion, the dielectric constant of the solvent plays a role on the charge and condensing force of DNA - hexamine cobalt （Ⅲ） complex.