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Double-crosslinked reversible redox-responsive hydrogels based on disulfide–thiol interchange
Journal of Polymer Science Part A: Polymer Chemistry Pub Date : 2019-11-14 , DOI: 10.1002/pola.29539
Yunjiao Che 1, 2 , Stefan Zschoche 1 , Franziska Obst 1, 2 , Dietmar Appelhans 1 , Brigitte Voit 1, 2
Affiliation  

We present novel redox-responsive hydrogels based on poly(N-isopropylacrylamide) or poly(acrylamide), consisting of a reversible disulfide crosslinking agent N,N′-bis(acryloyl)cystamine and a permanent crosslinking agent N,N′-methylenebisacrylamide for microfluidic applications. The mechanism of swelling/deswelling behavior starts with the cleavage and reformation of disulfide bonds, leading to a change of crosslinking density and crosslinking points. Raman and ultraviolet-visible spectroscopy confirm that conversion efficiency of thiol–disulfide interchange up to 99%. Rheological analysis reveals that the E modulus of hydrogel is dependent on the crosslinking density and can be repeatedly manipulated between high- and low-stiffness states over at least 5 cycles without significant decrease. Kinetic studies showed that the mechanical strength of the gels changes as the redox reaction proceeds. This process is much faster than the autonomous diffusion in the hydrogel. Moreover, cooperative diffusion coefficient (Dcoop) indicates that the swelling process of the hydrogel is affected by the reduction reaction. Finally, this reversibly switchable redox behavior of bulky hydrogel could be proven in microstructured hydrogel dots through short-term photopatterning process. These hydrogel dots on glass substrates also showed the desired short response time on cyclic swelling and shrinking processes known from downsized hydrogel shapes. Such stimuli-responsive hydrogels with redox-sensitive crosslinkers open a new pathway in exchanging analytes for sensing and separating in microfluidics applications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2590–2601

中文翻译:

基于二硫键-硫醇交换的双交联可逆氧化还原响应水凝胶

我们提出了基于聚(N-异丙基丙烯酰胺)或聚(丙烯酰胺)的新型氧化还原响应水凝胶,由可逆的二硫化物交联剂N , N '-双(丙烯酰基)胱胺和永久性交联剂N , N '-亚甲基双丙烯酰胺组成微流体应用。溶胀/去溶胀行为的机理始于二硫键的断裂和重组,导致交联密度和交联点的变化。拉曼和紫外-可见光谱证实硫醇-二硫化物交换的转化效率高达 99%。流变分析表明,E水凝胶的模量取决于交联密度,并且可以在至少 5 个循环内在高刚度和低刚度状态之间反复操作而不会显着降低。动力学研究表明,凝胶的机械强度随着氧化还原反应的进行而变化。这个过程比水凝胶中的自主扩散要快得多。此外,协同扩散系数 ( D coop) 表明水凝胶的溶胀过程受还原反应的影响。最后,可以通过短期光图案化过程在微结构水凝胶点中证明大体积水凝胶的这种可逆可切换的氧化还原行为。玻璃基板上的这些水凝胶点还显示出对缩小水凝胶形状已知的循环膨胀和收缩过程所需的短响应时间。这种具有氧化还原敏感交联剂的刺激响应水凝胶开辟了一条新途径,用于交换分析物以在微流体应用中进行传感和分离。© 2019 Wiley Periodicals, Inc. J. Polym。科学,A 部分:Polym。化学。2019 , 57 , 2590–2601
更新日期:2019-11-14
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