Biomaterials Research Group, School of Materials, The University of Manchester , MSS Tower, Manchester M13 9PL, United Kingdom.
Injury and Repair, Institute for Inflammation and Repair, Faculty of Medical and Human Sciences, University of Manchester , Oxford Road, Manchester, M13 9PT, United Kingdom.
Biomacromolecules. 2016 Jul 11;17(7):2448-58. doi: 10.1021/acs.biomac.6b00593. Epub 2016 Jun 16.
In this study hydrogel composites are investigated that contain sacrificial pH-responsive collapsed hollow particles (CHPs) entrapped within a poly(acrylamide) (PAAm) network. The CHPs were prepared using a scalable (mainly) water-based method and had a bowl-like morphology that was comparable to that of red blood cells. The CHPs were constructed from poly(methyl methacrylate-co-methacrylic acid), which is a pH-responsive copolymer. The PAAm/CHP composite morphology was probed with optical microscopy, CLSM and SEM. These data showed the CHPs were dispersed throughout the PAAm network. Inclusion of the CHPs within the gel composites increased the modulus in a tunable manner. The CHPs fragmented at pH values greater than the pKa of the particles, and this process decreased the gel modulus to values similar to that of the parent PAAm hydrogel. CHPs containing a model drug were used to demonstrate pH-triggered release from PAAm/CHP and the release kinetics obeyed Fickian diffusion. The composite gels had low cytotoxicity as evidenced by Live/Dead and MTT assays. The hydrogel composites showed dual action pH-triggered softening with simultaneous drug release which occurred without a volume increase. The hydrogel composites may have potential application as enteric gels or for intra-articular drug delivery.
本研究考察了含有牺牲型 pH 响应塌陷空心粒子 (CHP) 的水凝胶复合材料，这些 CHP 被包埋在聚丙烯酰胺 (PAAm) 网络中。CHP 是使用可扩展（主要是）基于水的方法制备的，具有与红细胞相当的碗状形态。CHP 由聚（甲基丙烯酸甲酯-共-甲基丙烯酸）构成，这是一种 pH 响应共聚物。使用光学显微镜、CLSM 和 SEM 研究了 PAAm/CHP 复合材料的形态。这些数据表明 CHP 均匀分散在 PAAm 网络中。CHP 的加入以可调的方式增加了凝胶的模量。当 pH 值大于颗粒的 pKa 时，CHP 会发生碎裂，从而使凝胶的模量降低到与原始 PAAm 水凝胶相似的值。使用含有模型药物的 CHP 来证明 PAAm/CHP 的 pH 触发释放，释放动力学符合菲克扩散定律。活/死和 MTT 测定表明，复合凝胶的细胞毒性低。水凝胶复合材料具有双重 pH 触发软化作用，同时伴随着药物释放，且没有体积增加。水凝胶复合材料可能具有作为肠溶凝胶或用于关节内药物输送的潜在应用。
