Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, 138634, Singapore.
Department of Materials Science and Engineering, National University of Singapore (NUS), 9 Engineering Drive 1, 117576, Singapore.
Chem Asian J. 2022 Nov 2;17(21):e202200621. doi: 10.1002/asia.202200621. Epub 2022 Sep 27.
Thermogels, a class of hydrogels which show spontaneous sol-gel phase transition when warmed, are an important class of soft biomaterials. To date, however, most amphiphilic polymers that are able to form thermogels in aqueous solution are uncharged, and the influence of ionisable groups on thermogelation are largely unknown. Herein, we report the first example of a polyanionic amphiphilic multi-block copolymer, containing multiple pendant carboxylate groups, that can form transparent thermogels spontaneously when warmed up to physiological temperature. We demonstrate that introducing negative charges onto thermogelling polymers could significantly alter the properties of the micelles and thermogels formed. Furthermore, the polymer's polyanionic character provides new options for modulating the gel rheological properties, such as stiffness and gelation temperatures, through electrostatic interactions with different cations. We also demonstrated that the polyanionic thermogel allowed slower sustained release of a cationic model drug compound compared to an anionic one over 2 weeks. The findings from our study demonstrate exciting new possibilities for advanced biomedical applications using charged polyelectrolyte thermogel materials.
温敏水凝胶是一类在升温时能够自发发生溶胶-凝胶相转变的水凝胶，是一类重要的软物质材料。然而，迄今为止，大多数能够在水溶液中形成温敏水凝胶的两亲聚合物都是不带电荷的，离子化基团对温敏水凝胶形成的影响在很大程度上仍是未知的。在此，我们报道了第一个阴离子型两亲性多嵌段共聚物的例子，该共聚物含有多个侧挂羧酸盐基团，在升温至生理温度时能够自发形成透明的温敏水凝胶。我们证明，在温敏聚合物上引入负电荷可以显著改变形成的胶束和温敏水凝胶的性质。此外，聚合物的阴离子特性通过与不同阳离子的静电相互作用，为调节凝胶流变性质（如硬度和胶凝温度）提供了新的选择。我们还证明，与阴离子模型药物化合物相比，该阴离子温敏水凝胶在 2 周内能够实现阳离子模型药物化合物的更缓慢持续释放。我们的研究结果表明，使用带电聚电解质温敏水凝胶材料进行先进的生物医学应用具有令人兴奋的新可能性。
