基因治疗法被认为是当今治疗糖尿病比较理想的方法。茶多糖生物相容性和降解性较好，无毒，具有降血糖生物活性。本课题将以含有肝细胞靶向因子-半乳糖基团的超支化茶多糖为原料，通过温和、高效的"硫醇-烯"点击化学合成法等方法，合成含多种胺基的阳离子超支化茶多糖衍生物作为载体，传输胰岛素基因，预期实现肝细胞靶向转染胰岛素基因，从而诱导肝细胞产生胰岛素并调节胰岛素的释放，降低血糖；将通过动物实验研究胰岛素基因复合物对1型糖尿病小鼠的治疗性能。本课题还将深入研究超支化茶多糖衍生物的半乳糖基团靶向因子、阳离子基团种类和含量、分子尺寸、超支化结构和葡萄糖基团营养因子对肝细胞靶向转染胰岛素基因的影响；将通过二维核磁共振波谱法、荧光光谱法、毛细管电泳法和圆二色谱法，深入研究胰岛素基因在转染过程中的构象变化对基因转染性能的影响。上述研究工作，目前国内外未见文献报道，具有理论和实际应用研究价值。

Gene therapy is considered as an effective method for the treatment of diabetes. Tea polysaccharides are bioactive polysaccharides with decreasing blood glucose, good biocompatibility, biodegradability and nontoxicity. In this project, the hyperbranched tea polysaccharide derivatives (HTPSs) with the targeting factor of liver cells (galactose residues) will be synthesized through some gentle and effective reactions such as thiol-ene click chemistry. They will be used as a gene carrier for the liver targeting delivery of the insulin genes. As expected, the insulin genes will be transfected in the liver cells, and then insulin will be expressed and released, resulting decreasing blood glucose. The gene therapeutic effect will be further investigated in mice with 1 type diabetes. Besides, the effect of the chemical structure of HTPSs on the liver targeting delivery of the insulin genes will be studied, such as the targeting factor, the kind and content of cationic groups, the molecular size, hyperbranched structures and the nutrition factor of glucose residues. The interaction between the insulin genes and HTPSs, and the conformation changes of the insulin genes during transfection will be investigated by 2D NMR, fluorescence spectroscopy, capillary electrophoresis and circular dichroism analyses. To our knowledge, the above mentioned research is still limited at present.