Synthesis and solution properties of pH responsive methoxy poly(ethylene glycol)-b-poly(γ-amino-ε-caprolactone)
作者:Jianjing Liu、Yan Zhang、Jinliang Yan、Meidong Lang
DOI:10.1039/c1jm10142k
日期:——
A series of water-soluble and cationic methoxy poly(ethylene glycol)-b-poly(γ-amino-ε-caprolactone) (mPEG-b-PACL) has been synthesized via ring opening polymerization of γ-(carbamic acid benzyl ester)-ε-caprolactone (γCABεCL) using mPEG as a macroinitiator and Sn(Oct)2 as a catalyst, and subsequent hydrolysis of the Cbz protecting groups under acidic conditions. The well-defined structure of copolymers was confirmed by 1H NMR and FTIR spectra. In addition, size exclusion chromatography (SEC) results indicated that the copolymer had a symmetric peak and a relatively narrow polydispersivity. The thermal properties were influenced by hydrogen bonding originating from the amino groups on the backbone based on differential scanning calorimetry (DSC) results. Furthermore, the solution properties have been investigated in water by a zetamasters instrument and dynamic light scattering (DLS). The results demonstrated that the aggregates exhibited a rich pH-responsive behavior with an appropriate PACL length. Successful formation of aggregates with spherical morphology was demonstrated beyond a critical PACL length by transmission electron microscopy (TEM). The mPEG-b-PACL block copolymer did not have any significant cytotoxicity against human dermal fibroblasts up to 500 μg mLâ1. Moreover, it has improved cell proliferation behavior according to MTT assays. Based on all these notable advantages, mPEG-b-PACL copolymer would be a potential candidate for biomedical and pharmaceutical applications.
通过使用mPEG作为大引发剂和Sn(Oct)2作为催化剂,对γ-(氨基甲酸苄酯)-ε-己内酯(γCABεCL)进行开环聚合反应,合成了一系列水溶性和阳离子的甲氧基聚乙二醇-b-聚(γ-氨基-ε-己内酯)(mPEG-b-PACL),随后在酸性条件下对Cbz保护基团进行水解。通过1H NMR和FTIR光谱证实了共聚物的明确结构。此外,尺寸排阻色谱(SEC)结果表明,共聚物具有对称峰和相对较窄的多分散性。根据差示扫描量热法(DSC)结果,热性质受来自主链上氨基的氢键影响。此外,通过zeta电位仪和动态光散射(DLS)在水中研究了溶液性质。结果表明,聚集体显示出丰富的pH响应行为,与适当的PACL长度相关。通过透射电子显微镜(TEM)证明,当超过临界PACL长度时,成功形成了具有球形形态的聚集体。mPEG-b-PACL嵌段共聚物对人皮肤成纤维细胞的细胞毒性不大于500 μg mL−1。此外,根据MTT实验结果,它改善了细胞增殖行为。基于这些显著优势,mPEG-b-PACL共聚物将成为生物医学和药物应用领域的潜在候选者。