生物降解高分子纳米球的制备

Preparation of Biodegradable Polymer Nanoshphere

利用丙交酯的开环聚合反应合成了一系列聚乳酸（ＰＬＡ）／ 聚乙二醇（ＰＥＧ）／ 聚乳酸（ＰＬＡ）三嵌段共聚物，采用１ Ｈ ＮＭＲ 分析和测定了共聚物的组成和分子量． 研究表明，当共聚物中ＰＬＡ链段分子量相同时，共聚物薄膜的吸水量随着ＰＥＧ 链段分子量和ＰＥＧ 含量的增大而提高；在３７ ℃、ｐＨ＝ ７－４ 的磷酸缓冲溶液中，共聚物在６０ ｄ 内可基本降解完全． 采用乳化溶剂蒸发技术制备了ＰＬＡ／ＰＥＧ／ＰＬＡ 三嵌段共聚物纳米球，其粒径受ＰＬＡ 链段及ＰＥＧ 链段分子量的影响，在１０３－６ ～１４１－６ ｎｍ 范围内，且大小均一，皆呈球形．

Biodegradable triblock copolymers were prepared from d,l lactide and poly(ethylene glycol) by bulk ring opening polymerization. The compositions and molecular weights of the copolymers were determined by 1H NMR. Keeping the molecular weight of PLA segment constant, the water adsorption capacity of the copolymer films increased with the increase of the molecular weight and content of PEG segment in copolymer. The PLA/PEG/PLA triblock copolymer could be degraded in phosphate buffer solution(pH=7 4) at 37 ℃ in 60 days. The spherical copolymer nanospheres with narrow unimodal size distribution 103 6～141 6 nm were prepared by one step emulsion method. Their sizes were influenced by PLA chain length and PEG chain length.