Synthesis and characterization of a thermosensitive hydrogel based on biodegradable amphiphilic PCL-Pluronic (L35)-PCL block copolymers

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• 作者：CaiBing Liu ; ChangYang Gong ; YiFeng Pan ; YangDe Zhang ; JiWei Wang ; MeiJuan Huang ; YongSheng Wang ; Ke Wang ; MaLing Gou ; MingJing Tu ; et al.
• 关键词：Thermosensitive hydrogel ; Gel– ; sol transition ; Polycaprolactone (PCL) ; Pluronic ; Biodegradable
• 刊名：Colloids and Surfaces A: Physicochemical and Engineering Aspects
• 出版年：2007
• 出版时间：20 July 2007
• 年：2007
• 卷：302
• 期：1-3
• 页码：430-438
• 全文大小：715 K

文摘

A series of PCL–Pluronic–PCL biodegradable block copolymers were successfully synthesized by ring opening polymerization of -caprolactone (-CL) initiated by Pluronic (PEG–PPG–PEG) macromonomer, which were characterized by ¹H NMR and FTIR. Their aqueous solution displayed special gel–sol transition with temperature increased from 4 °C to 70 °C, when the concentration was above corresponding critical gel concentration (CGC). The gel–sol phase diagram was recorded using test tube-inverting method, which depended not only on the hydrophilic/hydrophobic balance in macromolecular structure, but also on heating history of copolymer's aqueous solution. As a result, the gel–sol transition temperature range could be altered according to its practical application, which would be very useful as injectable drug delivery system. To illuminate the mechanism of gel–sol transition, we introduced a typical double layers shell/core structure of PCL–Pluronic–PCL micelles here. The hydrophobic interactions and partly crystallization might be the key gelation machanism for such special gel–sol transition behavior of PCL–Pluronic–PCL aqueous solution.