Investigation of the Supramolecular Formation and Temperature Hysteresis Behavior of Chitosan-Iodine Complex and the Evaluation of Its Biological functionality

壳聚糖-碘复合物的超分子形成和温度滞后行为研究及其生物功能评价

• 批准号: 12650889
• 负责人: HIROFUMI Yajima
• 金额: $ 2.37万
• 依托单位: Tokyo University of Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650889/
• 关键词: Polysaccharide; Chitosan-Iodine Compley; Spectroscopic Properties; Structural Analysis; Molecular Simulation; Thermal Hystereisis Behavior; Molecular Assembly; Biological Functionality; 温度履歴挙動

The results obtained in the study period of 2000 - 2001 were summarized as follows:1) In order to rationalize the mechanism of the complexation of chitosan with iodine and clearly interpret its specific molecular characteristics, we have investigated the effects of the factors responsible for the complexation, such as the degree of deacetylation (DDA), side-chain species, and molecular weight of chitosan, the concentrations of the reagents, etc., on the physicochemical properties (spectral characteristics, structure, etc.). For comparison, the physicochemical properties of the iodine complexes of amylose, cellulose, and N-methyl chitosan with structural types different from chitosan were examined. Furthermore, the biological functionalities of the CM complexes, i. e., the antibacterial assay for E. coli and wound healing assay for NIH/3T3 cell (mouse normal fibroblast) were probed.2) The chitosan-iodine (CM) complex, which was prepared in acidic medium by our developed freezing-thawing … More method, exhibited absorption spectra with a peak at around 500-650 nm, and mutually split CD bands with opposite signs (+, -), regardless of the iodine/chitosan concentrations, temperature, DDA more than 50%, and molecular weight. These spectral characteristics were similar to those of amylose-iodine (Ami) complex, whose purple coloring is developed by the left-handed iodine/ iodide dimer exciton-coupled mechanism involving CT and CI. Furthermore, the resonance Raman and NMR spectroscopy measurements revealed that the iodine species responsible for the coloring of the Chl complexes is primarily ions, and the interaction sites in the D-glucosamine moiety in chitosan chains with bound iodine are hydroxyl groups on C-1, C-3, and C-4.3)The ChI complex showed a unique characteristic of thermal hysteresis behavior, i. e., an irreversible reaction process involved in complexation and color formation, regardless ofDDA, side-chain species, and molecular weight. However, such as the behavior were not observed for the Ami and Cel complexes.4)The structural studies based on analytical ultracentrifugation, and small-angle X-ray/neutron scattering for the Chl complexes revealed that the molecular assembly of extended chitosan chains plays a vital role in CM complexation, in which the CI complex forms an aggregate with a cylindrical structure composed of an inner polyiodide chain surrounded by an assembly of chitosan chains. The aggregate structural size was progressed with the reagent concentrations, following the increase in coloration ability.5)The MD simulation predicted that the irreversibility and thermal hysteresis behavior of the Chl complexes is a result of the transition of chitosan in solution from a crystalline-like extended conformation to a compact folded conformation. As a future work, analysis of the transition of the compact folded form-crystalline-like extended form in the restoration of CI complexation induced by freezing, and the stoichiometry and kinetics of the complexation will be in progress.6)At present, the information on the effective bioactivity for the CM complex has been obtained. The water-soluble N-methyl chitosan is predicted to have a bright prospect for multi-biofunctionality. The foregoing results have been reported in the published papers (4 subjects), proceedings (2 subjects), and the papers (20 subjects) in national and international science meetings. Less

短句来源2000 - 2001年的研究成果总结如下：1)为了进一步阐明壳聚糖与碘的络合作用机理，明确其具体的分子特性，研究了壳聚糖的脱乙酰度、侧链种类、分子量、试剂浓度等因素对碘与壳聚糖络合作用的影响；关于理化性质（光谱特性、结构等）。为了比较，考察了不同结构类型的直链淀粉、纤维素和n -甲基壳聚糖的碘配合物的理化性质。此外，我们还探讨了CM复合物的生物学功能，即对大肠杆菌的抗菌试验和对NIH/3T3细胞（小鼠正常成纤维细胞）的伤口愈合试验。2)采用冻融法在酸性介质中制备壳聚糖-碘（CM）配合物，无论碘/壳聚糖浓度、温度、DDA大于50%、分子量如何，其吸收谱峰均在500 ~ 650 nm处，CD谱带相互分裂，且具有相反的正负号（+,-）。这些光谱特征与直链糖-碘（Ami）配合物相似，其紫色是由左旋碘/碘二聚体激子耦合机制形成的，涉及CT和CI。此外，共振拉曼和核磁共振光谱测量表明，Chl配合物的显色主要是离子，壳聚糖链上d -氨基部分与结合碘的相互作用位点是C-1、C-3和C-4.3上的羟基。ChI配合物表现出独特的热滞后行为特征，即无论是否有dda，其络合和显色都是一个不可逆的反应过程。侧链种类和分子量。然而，Ami和Cel复合物没有观察到这种行为。4)基于解析超离心和小角度x射线/中子散射对Chl配合物的结构研究表明，扩展壳聚糖链的分子组装在CM络合中起着至关重要的作用，其中CI配合物形成由内聚碘链组成的圆柱形结构的聚集体，周围是壳聚糖链的组装。随著色能力的提高，骨料的结构尺寸随著试剂浓度的增加而增大。5) MD模拟预测了Chl配合物的不可逆性和热滞后行为是壳聚糖在溶液中由晶体状延伸构象转变为致密折叠构象的结果。在今后的研究工作中，将进一步分析冻结诱导的CI络合恢复过程中由致密折叠形态向结晶状扩展形态的转变，以及络合的化学计量学和动力学研究。6)目前已获得CM配合物的有效生物活性信息。水溶性n -甲基壳聚糖在多种生物功能方面具有广阔的应用前景。上述结果已在国内外科学会议上发表论文（4篇）、论文集（2篇）和论文（20篇）。少

项目成果

H.Yajima et al.: "Complex Formation of Chitosan with Iodine and its Structure and Spectro-scopic Properties-Molecular Assembly and Thermal Hysteresis Behavior"Int.J.Thermophys.. (in press). (2001)

H.Yajima 等人：“壳聚糖与碘的复合物形成及其结构和光谱特性 - 分子组装和热滞后行为”Int.J.Thermophys..（出版中）。

H. Yajima et al.,: "Small-Angle Neutron Scattering Study of the Structure of Chitosan-Iodine Complex with Contrast Variation Method"Activity Report Neutron Scattering Research (Japan). 7. 262-263 (2000)

H. Yajima 等人：“用对比度变化法研究壳聚糖-碘复合物结构的小角中子散射研究”中子散射研究活动报告（日本）。

H.Yajima., et al.: "Complex Formation of Chitosan with Iodine and its Structure and Spectroscopic Properties"Proceedings of the 14th Symposium on Thermophysical Properties (NIST & ASME). 14. 21-53 (2000)

H.Yajima., et al.：“壳聚糖与碘的复合物形成及其结构和光谱性质”第 14 届热物理性质研讨会论文集 (NIST)

H.Yajima et al.: "Small-Angle Neutron Scattering Study of the Structure of Chitosan-Iodine Complex with Contrast Variation Method"Activity Report Neutron Scattering Research (Japan). 7. 262-263 (2000)

H.Yajima等人：“用对比度变化法研究壳聚糖-碘复合物结构的小角中子散射研究”中子散射研究活动报告（日本）。

H. Yajima et al.: "Complex Formation of Chitosan with Iodine and its Structure and Spectroscopic Properties - Molecular Thermal Hysteresis Behavior"Int. J. Thermophys.. 22. 1265-1283 (2001)

H. Yajima 等人：“壳聚糖与碘的复合物形成及其结构和光谱性质 - 分子热滞行为”Int。