中文摘要：

窄分子量分布低聚壳聚糖CS_n（n表示壳聚糖的聚合度,n=6,8,11）和对二甲氨基苯甲醛（DMABA）通过缩合反应得到了新型的基于壳聚糖的希夫碱化合物DMABA-CS_n。利用荧光光谱法,同步荧光光谱法,圆二色谱法（CD）和等温滴定微量热法（ITC）研究了DMABA-CS_n与牛血清白蛋白（BSA）之间的相互作用。通过荧光光谱法探讨了DMABA-CS_n对BSA的荧光猝灭机制。结果表明,DMABA-CS_n（n=6,8,11）均能使BSA的荧光猝灭,猝灭机制是形成DMABA-CS_n/BSA复合物的静态猝灭。利用同步荧光光谱法和圆二色谱法考察了DMABA-CS_n对BSA构象的影响。研究结果表明,BSA的构象在DMABA-CS_n的溶液微环境中发生了变化。另外,ITC热力学测定结果（ΔH〈0,ΔS〈0,ΔG〈0）表明,BSA与DMABA-CS_n的作用过程是自发进行的放热过程,二者之间的作用力类型主要是氢键和疏水作用。同时,研究结果也说明在一定的分子量范围内,随着CS_n聚合度的增加,DMABA-CS_n更容易与BSA结合。研究结果为DMABA-CS_n（n=6,8,11）作为潜在药物的药理作用机制研究提供了一定的理论参考。

英文摘要：

The novel chitosan-based schiff bases DMABA-CS_n were synthesized by the concentration reaction of narrow molecular distribution,low molecular weight chitosan CS_n（nrepresents the degree of polymerization of chitosan,n=6,8,11）and 4-Dimethylaminobenzaldehyde（DMABA）.The binding reaction between DMABA-CS_nand bovine serum albumin（BSA）was studied with fluorescence spectroscopy,synchronous fluorescence spectropy,circular dichroism（CD）and isothermal tiration calorimetric（ITC）.The fluoresonance quenching mechanism between DMABA-CS_nand BSA was studied with fluorescence spectroscopy.The results indicated that DMABA-CS_n（n=6,8,11）had the ability to quench the fluorescence from BSA and the quenching mechanism was a static quenching process with complex formation of DMABA-CS_n/BSA.The effect of DMABA-CS_non the conformation of BSA was studied with synchronous fluorescence spectroscopy.The results suggested that the conformation of BSA was changed in the microenvironment of DMABA-CS_n.Based on the thermodynamic results,the type of binding force was determined between DMABA-CS_nand BSA.In addition,the thermodynamics results（ΔH0,ΔS0,ΔG0）with ITC determination indicated that the binding process between DMABA-CS_nand BSA was exothermic and spontaneous.What＇s more,the main binding force was hydrogen bond and hydrophobic interaction.At the same time,with the increase of polymerization degree of CS_nin a certain range of molecular weight,DMABA-CS_ncan be more easiliy combined with BSA.The research results have provided theoretical reference for the study on pharmacological mechanism of DMABA-CS_n（n=6,8,11）as potential drugs.