Do the properties of gels constructed by interlinking triply-responsive microgels follow from those of the building blocks?
Do the properties of gels constructed by interlinking triply-responsive microgels follow from those of the building blocks?
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DOI：
10.1039/c8sm01510d
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发表时间：
2019-01
期刊：
影响因子：
3.4
通讯作者：
Dongdong Lu;Mingning Zhu;Wenkai Wang;Shangli Wu;B. Saunders;D. Adlam;J. Hoyland;C. Hofzumahaus;S. Schneider;K. Landfester
中科院分区：
文献类型：
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作者：
Dongdong Lu;Mingning Zhu;Wenkai Wang;Shangli Wu;B. Saunders;D. Adlam;J. Hoyland;C. Hofzumahaus;S. Schneider;K. Landfester
微凝胶（mg）是可膨胀的交联聚合物胶体。它们也可以作为构建纳米结构水凝胶的唯一构建块，这种水凝胶被称为双交联微凝胶（DX mg）。本文研究了由低聚（乙二醇）甲基丙烯酸酯（OEGMA）、2-（2-甲氧基乙氧基）甲基丙烯酸乙酯（MEO2MA）、甲基丙烯酸（MAA）和邻硝基苯基紫外光切割交联剂组成的新型三响应型DX mg。mg会随着温度和pH值的变化而膨胀或收缩。使用蒙特卡罗模拟的通用模型对这些行为进行了合理化。当紫外线照射时，由于nPh的光裂解，mg也会降解。DX mg由mg组装成可注射的对髓核细胞无细胞毒性的凝胶。DX mg和mg的响应特性比较表明，前者的温度和pH响应主要受后者的控制。然而，我们发现了两个关键的差异。首先，虽然增加MG构建块中的交联剂mol% (x)并没有改变MG颗粒的膨胀，但DX MG凝胶的压缩模量(E)和膨胀受到x的强烈影响。凝胶的E值可以使用x进行调节，这是DX MG的潜在有用的新观察结果。其次，与mg的行为相比，DX mg的紫外线照射增强了凝胶的机械光稳定性。我们发现DX mg的性质并不简单地遵循母mg的性质，并提出了解释这种差异的机制。本研究中提出的多反应性DX mg新家族在软组织修复中有潜在的应用，可作为注射凝胶或凝胶植入物，报道了灭菌。
Microgels (MGs) are swellable crosslinked polymer colloids. They can also be used as the only building block to construct nanostructured hydrogels which are denoted as doubly crosslinked microgels (DX MGs). Here, new triply responsive DX MGs comprised of interlinked MGs of oligo(ethylene glycol)methacrylate (OEGMA), 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA), methacrylic acid (MAA) and a o-nitrobenzyl-based UV photocleavable crosslinker are investigated. The MGs swelled or collapsed in response to temperature and pH changes. These behaviours were rationalised with a generic model using Monte Carlo simulations. The MGs also degraded when UV irradiated due to photocleavage of nPh. DX MGs were assembled from the MGs to give injectable gels that were not cytotoxic to nucleus pulposus cells. Comparison of the responsive properties of the DX MGs and MGs showed that the temperature and pH responses of the former were mostly governed by the latter. However, two key differences were found. Firstly, whilst increasing the crosslinker mol% in the MG building blocks (x) did not change MG particle swelling, the compression modulus (E) and swelling of the DX MG gels were strongly affected by x. The E value for the gels was tuneable using x which is a potentially useful new observation for DX MGs. Secondly, UV irradiation of the DX MGs enhanced gel mechanical photostability in contrast to the behaviour of the MGs. We find that the properties of the DX MGs do not simply follow those of the parent MGs and propose mechanisms to account for the differences. The new family of multi-responsive DX MGs presented in this study have potential application for soft tissue repair as injectable gels or as gel implants which report sterilisation.