Feng Hao, Dong Chang-Ming
Department of Polymer Science & Engineering, School of Chemistry and Chemical Technology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
Biomacromolecules. 2006 Nov;7(11):3069-75. doi: 10.1021/bm060568l.
Biodegradable chitosan-graft-poly(L-lactide) (CS-g-PLLA) hybrid amphiphiles were prepared through direct grafting of a PLLA precursor to the backbone of CS. The average number of PLLA grafts per CS could be adjusted by the feed ratio of PLLA to CS, and it varied from 1.3 to 16.8. Moreover, both the crystallization rate and degree of crystallization of PLLA grafts with these graft copolymers could be adjusted by the chain length of PLLA and the number of PLLA grafts per CS, respectively. Meanwhile, CS-g-PLLA exhibited good solubility in some nonpolar and polar organic solvents compared with the original CS. Furthermore, self-assembled nanoparticles could be generated by direct injection of these graft copolymer solutions into distilled water, and their critical aggregation concentration decreased with increasing number of PLLA grafts per CS. The average size of the nanoparticles (25-103 nm) could be adjusted through the graft copolymer composition and the graft copolymer concentration, which was very different from the observations in ordinary PLLA-b-poly(ethylene oxide) amphiphiles. Significantly, this will provide a convenient method not only to combine the bioactive functions of CS with the good mechanical properties of biodegradable polymers, but also to generate nanoparticles with adjustable sizes for targeted drug release.
通过将聚乳酸（PLLA）前体直接接枝到壳聚糖（CS）主链上制备了可生物降解的壳聚糖接枝聚（L-乳酸）（CS-g-PLLA）杂化两亲物。每个CS上PLLA接枝的平均数量可通过PLLA与CS的进料比进行调节，其范围为1.3至16.8。此外，这些接枝共聚物中PLLA接枝的结晶速率和结晶度可分别通过PLLA的链长和每个CS上PLLA接枝的数量进行调节。同时，与原始CS相比，CS-g-PLLA在一些非极性和极性有机溶剂中表现出良好的溶解性。此外，通过将这些接枝共聚物溶液直接注入蒸馏水中可生成自组装纳米颗粒，并且它们的临界聚集浓度随着每个CS上PLLA接枝数量的增加而降低。纳米颗粒的平均尺寸（25 - 103 nm）可通过接枝共聚物组成和接枝共聚物浓度进行调节，这与普通聚乳酸-b-聚环氧乙烷两亲物中的观察结果有很大不同。值得注意的是，这不仅将提供一种方便的方法来结合CS的生物活性功能和可生物降解聚合物的良好机械性能，而且还能生成尺寸可调的纳米颗粒用于靶向药物释放。
