中文摘要：

聚氨基酸是天然氨基酸单体或其衍生物通过酰胺键连接而成的一类聚合物的统称.由于其具有优良的生物相容性、生物可降解性等优点,在生物医学等领域显示出广泛的应用前景.发展经济有效的氨基酸聚合方法一直是高分子化学研究中的重要课题.比如,ε-聚赖氨酸侧链存在有大量氨基,它与微生物作用可以破坏细胞膜,具有非常卓越的抗菌性能,被广泛用作化妆品添加剂、食品防腐剂等.然而,因缺乏合适的聚合方法,直到21世纪初人们仍主要依赖于发酵法获得低分子量（Mn〈4000）的ε-聚赖氨酸.为了能将廉价可再生的赖氨酸转化为高附加值的ε-聚赖氨酸,近年来我们课题组提出了利用氨基酸的成环形成内酰胺单体,再通过内酰胺开环聚合制备聚氨基酸的方法,并成功地通过这种开环聚合方法合成了原先主要依赖于发酵法才能制备的ε-聚赖氨酸,具有重要的工业价值.与传统的α-氨基酸的N-羧基内酸酐（NCA）开环聚合法相比,基于内酰胺的氨基酸聚合新方法具有诸多优点：内酰胺单体的合成简单,无需使用光气或其衍生物;内酰胺单体稳定性好,其分离纯化及储存都非常容易;可以大规模的制备高分子量聚氨基酸;更为重要的是,利用内酰胺开环聚合可以制备γ-聚谷氨酸及ε-聚赖氨酸等通过NCA聚合无法获得的功能性聚氨基酸.我们相信,利用氨基酸的成环形成内酰胺,再通过内酰胺开环聚合制备聚氨基酸的方法代表着未来氨基酸聚合发展的重要方向.

英文摘要：

Poly （amino acid） is an important biomimetic material due to its unique biocompatibility and potential application in gene transfection, drug delivery, and prevention of viral infections. For example,ε-poly- lysine （ε-PL） is an uncommon cationic homopolymer produced by the fermentation process. Due to its significant antimicrobial activity and nontoxicity to humans,ε-PL is now industrially produced as an additive in food and cosmetics, biodegradable fibers,highly water absorbable hydrogels and drug carriers. However,due to the lack of appropriate polymerization method,6-PL is now produced mainly by a fermentation process. The ~- PL with a molecular weight less than 4 × 103 is obtained by biosynthetic method and no copolymers composed of lysine and other amino acids can be found in the producer strains,probably because the two amino acids are polymerized by different enzymes. Consequently,the composition and properties of the resultant polymers are hard to regulate. Here, we report a new chemical strategy, based on ring-opening polymerization （ROP） of lactam,to obtain 6-PL with diverse molecular weight from renewable lysine monomer. Compared with ROP of lysine via the N-carboxyanhydride （NCA） intermediate, this new strategy for 6-PL, through ROP and without phosgene,allows for new opportunities in biomaterials applications. Moreover, this methodology may provide access to the production of γ-polyglutamate and β-poly （aspartic acid） from glutamic acid and aspartic acid monomers, respectively.