Kawaguchi T, Hanaichi T, Hasegawa M, Maruno S
Instrument and Analysis Center, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
J Mater Sci Mater Med. 2001 Feb;12(2):121-7. doi: 10.1023/a:1008961709559.
Three kinds of dextran-magnetite (DM) complexes were prepared using alkali-treated dextrans with molecular weights of 1900, 4200 and 9600, respectively. The number of dextrans binding to a magnetite core was determined. The number was proportional to the area of core surface and the area occupied by a dextran was 2.5 nm2 for molecular weight of 1900, 2.8 for 4200 and 3.8 for 9600. The binding of dextrans to core may be conditioned by the conformation of dextran chains in water (possibly by the steric hindrance between dextrans covering core). Stability of the DM solution was examined at 80 degrees C. Aggregation and/or precipitation of DM particles were observed within two weeks. The stability of DM solution was found to increase with increasing molecular weight of dextran. The dissociation of dextran from the core may cause the aggregation and subsequent precipitation of DM particles (the dissociation constant at 20 degrees C, 3.7 x 10(-6) for a molecular weight of 1900 and 5.4 x 10(-7) for 9600).
分别使用分子量为1900、4200和9600的碱处理葡聚糖制备了三种葡聚糖 - 磁铁矿（DM）复合物。测定了与磁铁矿核心结合的葡聚糖数量。该数量与核心表面面积成正比，对于分子量为1900的葡聚糖，其占据的面积为2.5 nm²，对于4200的为2.8，对于9600的为3.8。葡聚糖与核心的结合可能受水中葡聚糖链构象的影响（可能是覆盖核心的葡聚糖之间的空间位阻）。在80℃下检测了DM溶液的稳定性。在两周内观察到DM颗粒的聚集和/或沉淀。发现DM溶液的稳定性随着葡聚糖分子量的增加而提高。葡聚糖从核心的解离可能导致DM颗粒的聚集和随后的沉淀（20℃下的解离常数，分子量为1900时为3.7×10⁻⁶，9600时为5.4×10⁻⁷）。
