Santra Subrata, Sk Mursed A, Mondal Arun, Molla Mijanur R
Department of Chemistry, University of Calcutta, 92 A.P.C. Road, Calcutta 700009, India.
Langmuir. 2020 Jul 21;36(28):8282-8289. doi: 10.1021/acs.langmuir.0c01474. Epub 2020 Jul 9.
The self-assembly of a stimuli-responsive amphiphilic polymer has been of great interest in the area of targeted drug delivery applications. In this article, a new amphiphilic polyurethane with a hydrophobic backbone consisting of a redox-responsive self-immolative unit and hydrophilic pendant triethylene glycol, which is periodically grafted on the backbone by a tertiary amine group, has been designed and synthesized. This amphiphilic polymer self-assembles into a micellar nanostructure (investigated by dynamic light scattering and transmission electron microscopy) in an aqueous medium and shows guest encapsulation property. Furthermore, the pH-responsive nature leads to the formation of a positively charged nanoassembly at a tumor-relevant pH (∼6.5-6.8), which is probed by zeta potential measurements. As the backbone was constructed with self-immolative, redox-responsive functionality, degradation of the polymer was observed in the presence of a reducing agent, glutathione (GSH), which results in disassembly of the self-assembled structure followed by guest release as probed by UV-vis spectroscopy. The triggered degradation and pH-specific charge generation (from neutral to positive), we believe, will have implications in the design of biodegradable polymers as supramoleular scaffolds for biomedical applications.
刺激响应性两亲聚合物的自组装在靶向药物递送应用领域引起了极大的关注。在本文中，设计并合成了一种新型两亲聚氨酯，其疏水主链由氧化还原响应性自牺牲单元组成，亲水性侧链为三甘醇，通过叔胺基团周期性地接枝在主链上。这种两亲聚合物在水性介质中自组装成胶束纳米结构（通过动态光散射和透射电子显微镜研究），并表现出客体包封性能。此外，pH响应特性导致在肿瘤相关pH值（约6.5 - 6.8）下形成带正电的纳米聚集体，这通过zeta电位测量进行了探究。由于主链具有自牺牲、氧化还原响应功能，在还原剂谷胱甘肽（GSH）存在下观察到聚合物降解，这导致自组装结构解体，随后通过紫外可见光谱法检测到客体释放。我们认为，触发的降解和pH特异性电荷产生（从中性到正性）将对作为生物医学应用超分子支架的可生物降解聚合物的设计产生影响。
