聚谷氨酸苄酯-聚乙二醇-聚谷氨酸苄酯嵌段共聚物的圆二色光谱分析

Circular dichroism spectrum analysis of poly(benzyl L-glutamate)/poly(ethylene glycol)/poly(benzyl L-glutamate) block copolymer

用三乙胺和双端氨基聚乙二醇分别引发经酯化、环化等处理的谷氨酸开环聚合制备聚谷氨酸苄酯(PBLG)和聚谷氨酸苄酯-聚乙二醇-聚谷氨酸苄酯嵌段共聚物(PBLG-PEG-PBLG,GEG)。采用圆二色光谱对聚合物溶液的旋光性进行分析,以确定共聚物中PBLG嵌段的构型和含量。结果表明,均聚物和共聚物中的PBLG嵌段都以α-螺旋构型存在,中间的PEG不扰乱其构型,通过聚合物的圆二色性(circular dichroism,CD)计算出的PBLG嵌段含量与核磁共振(nuclearmagnetic resonance,NMR)所得结果基本一致。

Poly （ γ-benzyl L-glutamate） and poly （ γ-benzyl L-glutamate）/poly （ ethylene glycol）/poly （ γ-benzyl L-glu- tamate） （PBLG-PEG-PBLG, GEG） was prepared by ring-opening polymerization of glutamate after esterification and ring formation using triethylene amine and amino-terminated polyethyleneglycol as initiators, respectively. The rotation of copolymer solution was analyzed by circular dichroism spectrum to determine the configuration and content of PBLG block in copolymer. The results showed that PBLG block existed in α-helical configuration, PEG did not affect its configuration, and the content calculated from the rotatory intensity agreed with the data from ^1H - NMR spectra.