Pore structure in supermacroporous polyacrylamide based cryogels
Pore structure in supermacroporous polyacrylamide based cryogels
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DOI：
10.1039/b510010k
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发表时间：
2005-10-14
期刊：
影响因子：
3.4
通讯作者：
Galaev', IY
中科院分区：
文献类型：
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作者：
Plieva, FM;Karlsson, M;Galaev', IY
通过改变初始反应混合物中单体的含量和所使用的交联剂来控制大孔聚丙烯酰胺凝胶(所谓的冷冻胶)的孔径和孔壁厚度。随着初始反应混合物中单体浓度的增加，PAAM-冷冻胶的孔壁厚度增加。超大孔PAAM-冷冻胶的孔容在70-93%之间，并随反应进料中单体浓度的增加而减小。使用环境扫描电子显微镜(ESEM)显示了PAAM-冷冻胶的多孔结构，从而可以监测PAAM-冷冻胶的脱水过程。以不同单体浓度的饲料为原料，研究了低分子量靶向铜(II)离子和高分子量靶蛋白溶菌酶共价偶联到聚合物骨架上的配体的可及性。随着反应进料中单体浓度的增加，结合的铜(II)离子的量呈线性增加，这表明所有的配体对小靶标都是平等的。相反，溶菌酶的结合在单体浓度约为18%时显示出明显的最大值，这表明只有存在于孔壁表面的粘液才能接触到高分子量靶标。
Pore size and thickness of pore walls in macroporous polyacrylamide gels, so-called cryogels (pAAm-cryogels), were controlled by varying the content of monomers in the initial reaction mixture and the cross-linker used. The thickness of pore walls in pAAm-cryogels increased with increasing concentration of monomers in the initial reaction mixture. Pore volume in the supermacroporous pAAm-cryogels was in the range of 70-93% and decreased with increasing concentration of monomers in the reaction feed. The porous structure of the pAAm-cryogels was visualized using environmental scanning electron microscopy (ESEM) that allowed monitoring of the dehydration process in pAAm-cryogels. The accessibility of ligands covalently coupled to the polymer backbone for low molecular weight target, Cu(II) ions, and high molecular weight target, the protein lysozyme, was assessed for pAAm-cryogels produced from feeds with different monomer concentration. The amount of bound Cu(II) ions increased linearly with increasing monomer concentration in the reaction feed, suggesting that all ligands are equally accessible for small targets. On the contrary, lysozyme binding demonstrated a clear maximum at monomer concentration about 18% suggesting that only ligrands present at the surface of pore walls are accessible for high molecular weight targets.