Abstract Herein, a novel kind of reduction and thermal dual-responsive polymer was synthesized by direct condensation polymerization of poly(ethylene glycol) (PEG) and 3,3′-dithiodipropanoic acid (DTPA). The resulting PEG-DTPA copolymers were soluble in water at room temperature and exhibited reversible thermal-responsive behaviors. The cloud point temperatures of PEG-DTPA copolymers were highly tunable dependent on the polymer concentration and the length of PEG segment. Additionally, the PEG-DTPA copolymers exhibited reduction-responsive behavior due to the presence of disulfide linkage groups in the backbone. This reduction-responsive property allowed the PEG-DTPA copolymers to be used in a drug delivery system. Thus, a triblock copolymer composed of mPEG2k and PEG400-DTPA copolymer was synthesized. The obtained copolymers could self-assemble into spherical micelles and exhibited thermal and reduction dual-responsive structure-variations in aqueous media. Furthermore, the hydrophobic Nile Red was effectively encapsulated into the micelles. The micelles maintained excellent reduction-responsive properties and can release drugs by reduction triggering. These results suggested that the PEG-DTPA copolymer may be promising for use as reduction and thermal dual-responsive drug carriers in cancer therapy.

中文翻译：

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一种还原敏感的热响应聚合物：合成、表征和在药物控释中的应用

摘要 在此，通过聚乙二醇（PEG）和3,3'-二硫代二丙酸（DTPA）直接缩聚合成了一种新型的还原热双响应聚合物。所得 PEG-DTPA 共聚物在室温下可溶于水并表现出可逆的热响应行为。PEG-DTPA 共聚物的浊点温度高度可调，取决于聚合物浓度和 PEG 链段的长度。此外，由于骨架中存在二硫键基团，PEG-DTPA 共聚物表现出还原响应行为。这种还原响应特性允许将 PEG-DTPA 共聚物用于药物递送系统。因此，合成了由 mPEG2k 和 PEG400-DTPA 共聚物组成的三嵌段共聚物。所得共聚物可以自组装成球形胶束，并在水性介质中表现出热和还原双响应结构变化。此外，疏水的尼罗红被有效地包裹在胶束中。胶束保持优异的还原响应特性，可以通过还原触发释放药物。这些结果表明 PEG-DTPA 共聚物有望在癌症治疗中用作还原和热双响应药物载体。