A versatile approach to reducible vinyl polymers via oxidation of telechelic polymers prepared by reversible addition fragmentation chain transfer polymerization.
A versatile approach to reducible vinyl polymers via oxidation of telechelic polymers prepared by reversible addition fragmentation chain transfer polymerization.
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DOI：
10.1021/bm0702049
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发表时间：
2007-05
影响因子：
6.2
通讯作者：
Yezi You;D. Manickam;Qing-hui Zhou;D. Oupický
中科院分区：
文献类型：
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作者：
Yezi You;D. Manickam;Qing-hui Zhou;D. Oupický
生物可降解聚合物的合成由于其在一系列应用中的重要性而受到极大的关注，包括复杂的生物医学装置和防止环境污染。1生物可降解聚合物材料通常含有化学键，在温和条件下可以容易地化学或生物裂解。2-7含二硫键的可还原聚合物是制备可生物降解材料中可水解聚合物的一种有吸引力的替代物。8-12二硫化物基团可以在还原剂存在下裂解，并且二硫化物/硫醇对的氧化还原电位可以通过反应条件容易地控制。这些含二硫化物的可还原聚合物可以通过氧化二硫代官能化的聚合物前体或通过使用含二硫化物的单体或交联剂来合成。4，8，9，11-16目前对可还原聚合物的兴趣主要是由它们在药物和基因递送应用中的有利性质驱动的，并且许多实际使用的可还原聚合物是基于肽的。乙烯基聚合物是目前使用的最重要的一类聚合物材料。其中许多在分子成像、纳米医学以及药物和基因递送方面具有潜在的应用。然而，由于它们的CC骨架的稳定性，这些聚合物不易于生物降解，这显著限制了它们的生物医学应用。因此，在乙烯基聚合物中引入可生物降解的二硫键有可能成为一个重要的研究领域。最近，Matyjaszewski et.和Armes et. Al使用基于二硫化物的二乙烯基单体的原子转移自由基聚合来制备可降解凝胶，并且使用基于二硫化物的引发剂来制备在中心含有二硫键的线性聚合物。可逆加成断裂链转移（RAFT）聚合是一种非常通用的、可控的自由基聚合技术，可用于合成具有窄分子量多分散性的明确聚合物结构。20-26 RAFT工艺适用于各种单体，并且可以在各种条件下进行。基于RAFT聚合的机理，使用双官能RAFT试剂的RAFT聚合产生在两个位置均含有转移剂残基的大分子。
Synthesis of biodegradable polymers has received significant attention due to its importance in a range of applications, including sophisticated biomedical devices and prevention of environmental pollution. 1 Biodegradable polymer materials usually contain chemical bonds that can be easily cleaved chemically or biologically under mild conditions. 2-7 Disulfidecontaining reducible polymers represent an attractive alternative to hydrolyzable polymers in the preparation of biodegradable materials. 8-12 The disulfide groups can be cleaved in the presence of reducing agents, and the redox potential of the disulfide/thiol couple can be easily controlled by the reaction conditions. These disulfide-containing reducible polymers can be synthesized either by an oxidation of dithio-functionalized polymer precursors or by using disulfide-containing monomers or cross-linkers. 4, 8, 9, 11-16 Interest in the reducible polymers is currently driven mainly by their favorable properties in drug and gene delivery applications and many of the practically used reducible polymers are based on peptides. 17, 18 Vinyl polymers represent one of the most important classes of polymer materials currently in use. Many of them have potential applications in molecular imaging, nanomedicine, and drug and gene delivery. However, because of the stability of their CC backbone, these polymers are not readily susceptible to biodegradation, which significantly limits their biomedical applications. Introducing biodegradable disulfide bonds into vinyl polymers has therefore potential to become an important area of research. Recently, Matyjaszewski et. al and Armes et. al used atom transfer radical polymerization of disulfide-based divinyl monomers to prepare degradable gels and disulfide-based initiators to prepare a linear polymer containing a disulfide bond in the center. 10, 19 However, synthesis of reducible vinyl polymers containing multiple disulfide bonds in the backbone has been seldom explored until now.Reversible addition fragmentation chain transfer (RAFT) polymerization is an extremely versatile, controlled free radical polymerization technique for the synthesis of well-defined polymer architectures with narrow molecular weight polydispersity. 20-26 The RAFT process is applicable to a wide range of monomers and can be performed under a broad range of conditions. On the basis of the mechanism of RAFT polymerization, RAFT polymerization using a difunctional RAFT agent yields macromolecules containing transfer agent residues at both