Anisotropic pH-Responsive Hydrogels Containing Soft or Hard Rod-Like Particles Assembled Using Low Shear
Anisotropic pH-Responsive Hydrogels Containing Soft or Hard Rod-Like Particles Assembled Using Low Shear
复制标题
DOI：
10.1021/acs.chemmater.7b00110
复制
发表时间：
2017-04-11
影响因子：
8.6
通讯作者：
Armes, Steven P.
中科院分区：
文献类型：
--
作者：
Milani, Amir H.;Fielding, Lee A.;Armes, Steven P.
开发了一种简单而通用的低剪切方法，用于组装含有排列的棒状颗粒（RLP）的水凝胶，所述棒状颗粒是双折射的并且表现出pH触发的各向异性溶胀。通过向pH响应性纳米凝胶（NG）和RLP的混合物施加低剪切（0.1s（-1））来制备各向异性复合水凝胶。NG，其中含有高甲基丙烯酸含量，作为剪切传递媒介物和宏观交联剂的各向异性凝胶形成。三个模型RLP系统进行了研究：（一）软三嵌段共聚物蠕虫，（二）硬自组装β-折叠肽纤维，和（三）弹性模量纳米晶纤维素纤维。RLP对齐确认使用偏振光成像，原子力显微镜，和小角X-射线散射以及模量和各向异性溶胀实验。出乎意料的是，含有软共聚物蠕虫的复合凝胶显示出最明显的各向异性溶胀。共聚物蠕虫使更高的RLP负载比可能的刚性RLP。对于固定的RLP加载，各向异性膨胀的程度增加内RLP粘结强度。本文所展示的各向异性凝胶构造的简便和通用方法有望实现用于应变传感或用于软组织修复的生物材料的新应用。
A simple and versatile low-shear approach for assembling hydrogels containing aligned rod-like particles (RLPs) that are birefringent and exhibit pH-triggered anisotropic swelling is developed. Anisotropic composite hydrogels are prepared by applying low shear (0.1 s(-1)) to mixtures of pH-responsive nanogels (NGs) and RLPs. The NGs, which contained high methacrylic acid contents, acted as both shear transfer vehicles and macro-cross-linkers for anisotropic gel formation. Three model RLP systems are investigated: (0 soft triblock copolymer worms, (ii) stiff self-assembled beta-sheet peptide fibers, and (iii) ultrahigh modulus nanocrystalline cellulose fibers. RLP alignment was confirmed using polarized light imaging, atomic force microscopy, and small-angle X-ray scattering as well as modulus and anisotropic swelling experiments. Unexpectedly, the composite gel containing the soft copolymer worms showed the most pronounced anisotropy swelling. The copolymer worms enabled higher RLP loadings than was possible for the stiffer RLPs. For fixed RLP loading, the extent of anisotropic swelling increased with intra-RLP bonding strength. The facile and versatile approach to anisotropic gel construction demonstrated herein is expected to enable new applications for strain sensing or biomaterials for soft tissue repair.