Xiao Yan, Wang Jianqiang, Zhang Jun, Heise Andreas, Lang Meidong
Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Department of Pharmaceutical and Medicinal Chemistry, Royal College of Surgeons in Ireland, St. Stephens Green, Dublin 2, Ireland.
Biopolymers. 2017 Oct;107(10). doi: 10.1002/bip.23038. Epub 2017 Aug 18.
Copolypept(o)ides of polysarcosine (PSar) and poly(N-isopropyl-L-glutamine) (PIGA) with random and block sequence structures were synthesized by ring-opening polymerization (ROP) of sarcosine N-carboxyanhydrides (Sar-NCA) and γ-benzyl-l-glutamate N-carboxyanhydrides (BLG-NCA) and post modification. With different distribution of Sar along the main chain, H-bonding pattern and secondary structure of polypeptides were turned, as well as aggregation and gelation behavior. Both copolypept(o)ides formed hydrogels above their critical gelation concentrations (CGCs) without thermo-sensitivity, which was normally reserved for PEG copolypeptides (eg, PEG-b-PIGA). In particular, a different mechanism from previously reported micellar percolation or fibrillar entanglement was suggested for gelation of the random copolypept(o)ide. Therefore, hydrogels from copolymers of PSar and PIGA represented a new approach to construct easy-handling, biocompatible, biodegradable and thermo-stable gels that could potentially be applied in biomedical fields.
通过肌氨酸N-羧基酸酐（Sar-NCA）和γ-苄基-L-谷氨酸N-羧基酸酐（BLG-NCA）的开环聚合（ROP）及后修饰，合成了具有无规和嵌段序列结构的聚肌氨酸（PSar）和聚（N-异丙基-L-谷氨酰胺）（PIGA）的共多肽。随着Sar沿主链的不同分布，多肽的氢键模式和二级结构发生转变，其聚集和凝胶化行为也随之改变。两种共多肽在其临界凝胶浓度（CGC）以上形成水凝胶，且无热敏感性，而热敏感性通常是聚乙二醇共多肽（如PEG-b-PIGA）所具有的特性。特别地，对于无规共多肽的凝胶化，提出了一种与先前报道的胶束渗滤或纤维缠结不同的机制。因此，由PSar和PIGA的共聚物形成的水凝胶代表了一种构建易于处理、生物相容、可生物降解且热稳定的凝胶的新方法，这些凝胶有可能应用于生物医学领域。
