A pH-responsive carboxylic β-1,3-glucan polysaccharide for complexation with polymeric guests.
A pH-responsive carboxylic β-1,3-glucan polysaccharide for complexation with polymeric guests.
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DOI：
10.1039/c1ob05114h
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发表时间：
2011-05
影响因子：
3.2
通讯作者：
L. Liên;T. Shiraki;A. Dawn;Youichi Tsuchiya;D. Tokunaga;S. Tamaru;N. Enomoto;J. Hojo;S. Shinkai
中科院分区：
文献类型：
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作者：
L. Liên;T. Shiraki;A. Dawn;Youichi Tsuchiya;D. Tokunaga;S. Tamaru;N. Enomoto;J. Hojo;S. Shinkai
β-1，3-葡聚糖多糖的螺旋形成性质是具有生产基因载体、生物纳米材料和其他手性纳米线潜力的特征。以β-1，3-葡聚糖多糖凝胶多糖（Curlan，Cur）为原料，采用4-乙酰胺基-TEMPO/NaClO/NaClO（2）体系为氧化剂，一步氧化法成功制备了具有β-1，3-葡糖醛酸结构的羧基凝胶多糖（CurCOOH）。证明所得高分子量CurCOOH以100%纯度带有6-COOH基团。旋光色散（ORD）谱表明，所得的CurCOOH在不同pH值的水溶液中表现为水溶性单链。这一优势使我们能够使用CurCOOH作为聚合物主体，形成各种大分子复合物。例如，CuCOOH与单壁碳纳米管（SWNT）的络合导致水溶性一维结构，其在水溶液中形成稳定数月的分散体，并且比类似的带负电荷的聚丙烯酸（PAA）和聚甲基丙烯酸（PMAA）的SWNT络合物稳定得多。结果表明，在复合物中，SWNTs被少量的CurCOOH有效地包裹，使它们能够避免静电排斥。这种pH响应性的CurCOOH与阳离子水溶性聚噻吩（PT-1）形成非常稳定的复合物，其不仅通过疏水相互作用而且通过PT-1中的三甲基铵阳离子与CurCOOH中解离的阴离子COO（-）基团之间的静电吸引而稳定。所包含的PT-1仅在中性至碱性pH区域中具有CD活性，并且正的Cotton效应表明共轭主链在右手方向上扭曲。我们还发现，CurCOOH可以相互作用的聚胞苷酸（聚（C））只有在高NaCl浓度下，结合和释放的盐浓度的变化可以控制。因此，我们认为，带有可解离的COOH基团的CurCOOH可以作为一种新的潜在的聚合物主体，以构建适用于基因载体、生物传感器、手性聚合物组装体等的新型聚合物复合物。
The helix-forming nature of β-1,3-glucan polysaccharides is a characteristic that has potential for producing gene carriers, bio-nanomaterials and other chiral nanowires. Herein, carboxylic curdlan (CurCOOH) bearing the β-1,3-polyglucuronic acid structure was successfully prepared from β-1,3-glucan polysaccharide curdlan (Cur) by one-step oxidation using a 4-acetamido-TEMPO/NaClO/NaClO(2) system as the oxidant. The resulting high-molecular-weight CurCOOH was proved to bear the 6-COOH group in 100% purity. The optical rotatory dispersion (ORD) spectra indicated that the obtained CurCOOH behaves as a water-soluble single-strand in various pH aqueous media. This advantage has allowed us to use CurCOOH as a polymeric host to form various macromolecular complexes. For example, complexation of CurCOOH with single-walled carbon nanotubes (SWNTs) resulted in a water-soluble one-dimensional architecture, which formed a dispersion in aqueous solution that was stable for several months, and much more stable than SWNTs complexes of the similar negatively-charged polyacrylic acid (PAA) and polymethacrylic acid (PMAA). It was shown that in the complex, SWNTs are effectively wrapped by a small amount of CurCOOH, enabling them to avoid electrostatic repulsion. This pH-responsive CurCOOH formed a very stable complex with cationic water-soluble polythiophenes (PT-1), which was stabilized not only by the hydrophobic interaction but also by the electrostatic attraction between trimethylammonium cations in PT-1 and dissociated anionic COO(-) groups in CurCOOH. The included PT-1 became CD-active only in the neutral to basic pH region, and the positive Cotton effect suggested that the conjugated main chain is twisted in the right-handed direction. We also found that CurCOOH can interact with polycytidylic acid (poly(C)) only under high NaCl concentrations, the binding and release of which could be controlled by a change in the salt concentration. We believe, therefore, that CurCOOH bearing a dissociable COOH group can act as a new potential polymeric host to construct novel polymeric complexes applicable for gene carriers, biosensors, chiral polymer assemblies, etc.