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

1）为了阐明壳聚糖与碘络合的机理，阐明其分子特性，我们考察了壳聚糖的脱乙酰度、侧链种类、分子量、试剂浓度等因素对络合作用的影响，并对壳聚糖与碘络合的机理进行了研究。理化性质（光谱特征、结构等）。为了比较，碘络合物的直链淀粉，纤维素，和N-甲基壳聚糖与壳聚糖不同的结构类型的物理化学性质进行了检查。此外，CM配合物的生物功能，即。例如，对E. 2）采用冻融法在酸性介质中制备壳聚糖-碘（chitosan-iodine，CM）复合物 ...更多信息 方法，表现出吸收光谱，峰在500-650 nm附近，并且具有相反符号（+，-）的相互分裂的CD带，而与碘/壳聚糖浓度、温度、大于50%的DDA和分子量无关。这些光谱特征与直链淀粉-碘（Ami）复合物的光谱特征相似，Ami复合物的紫色是由涉及CT和CI的左手碘/碘化物二聚体激子耦合机制产生的。共振拉曼光谱和核磁共振光谱分析表明，导致Chl复合物显色的碘主要是离子，而壳聚糖链中D-氨基葡萄糖部分与碘的作用位点是C-1、C-3和C-4上的羟基。例如，一个不可逆的反应过程，涉及络合和颜色的形成，无论ofDDA，侧链物种，和分子量。然而，Ami和Cel复合物没有观察到这种行为。4）基于分析超离心和小角X射线/中子散射的Chl复合物的结构研究表明，延伸的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Cl络合物形成具有圆柱形结构的聚集体，所述圆柱形结构由被壳聚糖链的组装体包围的内部聚碘化物链组成。分子动力学模拟结果表明，Chl复合物的不可逆性和热滞行为是壳聚糖在溶液中由结晶状伸展构象向紧凑折叠构象转变的结果。作为未来的工作，对冷冻诱导的氯离子络合过程中紧密折叠-结晶状伸展形式的转变、络合的化学计量学和动力学的分析将继续进行。6）目前，CM络合物的有效生物活性信息已经获得。水溶性N-甲基壳聚糖具有良好的多生物功能性，具有广阔的前景。上述结果已在已发表的论文（4个主题）、会议录（2个主题）和国家和国际科学会议论文（20个主题）中报道。少

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