Thermoresponsive unimolecular micelles with a hydrophobic dendritic core and a double hydrophilic block copolymer shell

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• 作者：Shizhong Luo ; Congxiang Ling ; Xianglong Hu ; Xi Liu ; Shuaishuai Chen ; Mengcheng Han ; Jiang Xia
• 关键词：Unimolecular polymeric micelle ; Core– ; shell structure ; Laser light scattering ; Thermoresponsive
• 刊名：Journal of Colloid and Interface Science
• 出版年：2011
• 出版时间：1 January 2011
• 年：2011
• 卷：353
• 期：1
• 页码：76-82
• 全文大小：732 K

文摘

Biocompatible stimuli-responsive unimolecular polymeric micelles have attracted much interest due to their unique structures and potential applications in biomedical fields such as drug delivery and tissue engineering. Here, we report the preparation of dendritic unimolecular polymeric micelles with temperature sensitive shells via reversible addition–fragmentation transfer (RAFT) technique. A multi-arm star amphiphilic copolymer (H40-PDEA) with a hydrophobic hyperbranched polyester (Boltorn H40) as the core and the grafted poly(N,N-diethylacrylamide) (PDEA) as the shell was prepared using H40 based macroRAFT agent. And a dendritic unimolecular polymer (H40-PDEA–PDMA) with a double hydrophilic block copolymer (DHBC) [PDEA-b-poly(2-(dimethylamino)ethyl methacrylate) (PDEA-b-PDMA)] as the dual thermoresponsive shells was synthesized by H40-PDEA based macroRAFT agent. Both H40-PDEA and H40-PDEA–PDMA have a reversible phase transition behavior in aqueous solution. In particular, the unimolecular polymeric micelles H40-PDEA–PDMA with double thermoresponsive shells exhibit a two-stage phase transition behavior. Laser light scattering (LLS), UV–vis transmittance, excimer fluorescence measurements, and micro-differential scanning calorimetry (micro-DSC) were used in combination to probe the conformational changes of chains located at the inner layer and outer corona during the phase transition process.