Highly deformable hydrogels constructed by pH-triggered polyacid nanoparticle disassembly in aqueous dispersions.
Highly deformable hydrogels constructed by pH-triggered polyacid nanoparticle disassembly in aqueous dispersions.
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DOI：
10.1039/c8sm00325d
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发表时间：
2018-05
期刊：
影响因子：
3.4
通讯作者：
Wenkai Wang;Dongdong Lu;Mingning Zhu;Jennifer M. Saunders;Amir H. Milani;S. Armes;B. Saunders
中科院分区：
文献类型：
--
作者：
Wenkai Wang;Dongdong Lu;Mingning Zhu;Jennifer M. Saunders;Amir H. Milani;S. Armes;B. Saunders
大多数水凝胶是使用小分子单体制备的，但不幸的是，这种方法对于某些生物材料应用可能不可行。因此，已经建立了替代的凝胶构建策略，其包括使用预先形成的凝胶颗粒或微凝胶（MG）的共价互连。例如，共价连接pH响应性MG可以产生包含双重交联微凝胶（DX MG）的水凝胶。我们假设，这种DX MG的变形能力受到MG内交联存在的限制。因此，在这项研究中，我们设计了新的纳米颗粒（NP）为基础的凝胶的pH值溶胀的NP，不内部交联。合成了两种含有甲基丙烯酸（MAA）和丙烯酸乙酯（EA）或甲基丙烯酸甲酯（MMA）的多酸NP。PMAA-EA和PMAA-MMA NP随后使用甲基丙烯酸缩水甘油酯（GMA）进行乙烯基官能化，然后通过自由基交联形成凝胶。提高溶液pH值时，NP大部分分解，但一些自交联仍然是明显的。由基于EA和MMA的NP构建的凝胶具有比对照DX MG更大的断裂应变。研究了在固化过程中改变溶液pH值对使用PMAA-MMA-GMA NPs制备的凝胶的形态和力学性能的影响，观察到显着的变形性和优异的恢复性。该凝胶具有强烈的pH响应性，拉伸断裂应变高达420%，压缩断裂应变超过93%。一种优化的配方产生了最可变形和最可拉伸的凝胶，但使用NP或MG作为唯一的构建单元。
Most hydrogels are prepared using small-molecule monomers but unfortunately this approach may not be feasible for certain biomaterial applications. Consequently, alternative gel construction strategies have been established, which include using covalent inter-linking of preformed gel particles, or microgels (MGs). For example, covalently interlinking pH-responsive MGs can produce hydrogels comprising doubly crosslinked microgels (DX MGs). We hypothesised that the deformability of such DX MGs was limited by the presence of intra-MG crosslinking. Thus, in this study we designed new nanoparticle (NP)-based gels based on pH-swellable NPs that are not internally crosslinked. Two polyacid NPs were synthesised containing methacrylic acid (MAA) and either ethyl acrylate (EA) or methyl methacrylate (MMA). The PMAA-EA and PMAA-MMA NPs were subsequently vinyl-functionalised using glycidyl methacrylate (GMA) prior to gel formation via free-radical crosslinking. The NPs mostly disassembled on raising the solution pH but some self-crosslinking was nevertheless evident. The gels constructed from the EA- and MMA-based NPs had greater breaking strains than a control DX MG. The effect of varying the solution pH during curing on the morphology and mechanical properties of gels prepared using PMAA-MMA-GMA NPs was studied and both remarkable deformability and excellent recovery were observed. The gels were strongly pH-responsive and had tensile breaking strains of up to 420% with a compressive strain-at-break of more than 93%. An optimised formulation produced the most deformable and stretchable gel yet constructed using NPs or MGs as the only building block.