Preparation and Characterization of Polyion Complex Micelles with Phosphobetaine Shells

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• 作者：Keita Nakai ; Midori Nishiuchi ; Masamichi Inoue ; Kazuhiko Ishihara ; Yusuke Sanada ; Kazuo Sakurai ; Shin-ichi Yusa
• 刊名：Langmuir
• 出版年：2013
• 出版时间：August 6, 2013
• 年：2013
• 卷：29
• 期：31
• 页码：9651-9661
• 全文大小：499K
• 年卷期：v.29,no.31(August 6, 2013)
• ISSN：1520-5827

文摘

A pair of oppositely charged diblock copolymers, poly(2-(methacryloyloxy)ethyl phosphorylcholine)-block-poly((3-(methacryloylamino)propyl)trimethylammonium chloride) (PMPC-b-PMAPTAC) and poly(2-(methacryloyloxy)ethyl phosphorylcholine)-block-poly(sodium 2-(acrylamido)-2-methylpropanesulfonate) (PMPC-b-PAMPS), was prepared via reversible addition鈥揻ragmentation chain transfer radical polymerization using a PMPC-based macro chain transfer agent. The pendant phosphorylcholine group in the hydrophilic PMPC block has anionic phosphate and cationic quaternary amino groups, which are neutralized within the pendant group. Therefore, the mixing of aqueous solutions of PMPC-b-PMAPTAC and PMPC-b-PAMPS leads to the spontaneous formation of simple core鈥搒hell spherical polyion complex (PIC) micelles comprising of a segregated PIC core and PMPC shells. The PIC micelles were characterized using ¹H NMR spin鈥搒pin (T₂) and spin鈥搇attice relaxation times (T₁), diffusion-ordered NMR spectroscopy, static light scattering, dynamic light scattering (DLS), and transmission electron microscopy techniques. The hydrodynamic size of the PIC micelle depended on the mixing ratio of PMPC-b-PMAPTAC and PMPC-b-PAMPS; the maximum size occurred at the mixing ratio yielding stoichiometric charge neutralization. The PIC micelles disintegrated to become unimers with the addition of salts.