Polypeptide-b-Poly(Phenyl Isocyanide) Hybrid Rod-Rod Copolymers: One-Pot Synthesis, Self-Assembly, and Cell Imaging
Polypeptide-b-Poly(Phenyl Isocyanide) Hybrid Rod-Rod Copolymers: One-Pot Synthesis, Self-Assembly, and Cell Imaging
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多肽-b-聚（苯基异氰）杂化棒-棒共聚物：一锅法合成、自组装和细胞成像
DOI：
10.1002/marc.201500185
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发表时间：
2015-08-01
影响因子：
4.6
通讯作者：
Wu, Zong-Quan
中科院分区：
文献类型：
--
作者：
Shi, Sheng-Yu;He, Ya-Guang;Wu, Zong-Quan
以含手性薄荷基的苯基异氰酸酯单体为催化剂，通过一锅法合成了具有一定手性的L-谷氨酸苄酯-聚(4-氰基-苯甲酸-2-异丙基-5-甲基环己酯)杂化棒-棒两嵌段共聚物。圆二色谱和吸收光谱表明，由于手性侧链的诱导，嵌段共聚物的每个嵌段都具有稳定的螺旋构象，在溶液中具有可控的螺旋度。透射电子显微镜证实，由于L-和D-薄荷基对映体的手性诱导不同，两种非对映异构体聚合物以相反的手性自组装成螺旋纳米纤维。去掉PBLG链段上的苄基保护，可以得到生物相容性的两嵌段共聚物，即聚(L-谷氨酸)-聚(4-氰基-苯甲酸-2-异丙基-5-甲基-环己基酯)(PLGA-PPI)，它可以通过共溶剂诱导聚集自组装成定义良好的胶束。非常有趣的是，手性罗丹明发色团RhB(D)可以选择性地被包裹到手性聚合物胶束中，当用共聚焦显微镜直接监测时，它可以有效地内化到活细胞中。这一贡献将有助于开发螺旋度可控的新型棒棒生物相容性杂化嵌段共聚物，并可能为潜在的生物医学应用提供独特的手性材料。
Hybrid rod-rod diblock copolymers, poly(-benzyl L-glutamate)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PBLG-PPI), with determined chirality are facilely synthesized through sequential copolymerization of -benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and phenyl isocyanide monomers bearing chiral menthyl pendants using a Ni(cod)(bpy) complex as the catalyst in one-pot. Circular dichroism and absorption spectra reveal that each block of the block copolymers possesses a stable helical conformation with controlled helicity in solution due to the induction of chiral pendants. The two diastereomeric polymers self-assemble into helical nanofibrils with opposite handedness due to the different chiral induction of the L- and D-menthyl pendants, confirmed by transmission electron microscopy (TEM). Deprotection of the benzyl groups of the PBLG segment affords biocompatible amphiphilic diblock copolymers, poly(L-glutamic acid)-poly(4-cyano-benzoic acid 2-isopropyl-5-methyl-cyclohexyl ester) (PLGA-PPI), that can self-assemble into well-defined micelles by cosolvent induced aggregation. Very interestingly, a chiral rhodamine chromophores RhB(D) can be selectively encapsulated into the chiral polymeric micelles, which is efficiently internalized into living cells when directly monitored with a confocal microscope. This contribution will be useful for developing novel rod-rod biocompatible hybrid block copolymers with a controlled helicity, and may also provide unique chiral materials for potential bio-medical applications.