Chen Xiaodong, Wang Shanshan, Lu Meiling, Chen Yuying, Zhao Luhai, Li Wei, Yuan Qipeng, Norde Willem, Li Yuan
State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology , P.O. Box 53, 100029 Beijing, China.
Biomacromolecules. 2014 Jun 9;15(6):2166-71. doi: 10.1021/bm500327m. Epub 2014 May 28.
A light-responsive delivery system has been developed. It consists of gelly microspheres made of TEMPO-oxidized Konjac glucomannan (OKGM) polymers where the carboxyl (COO(-)) groups are cross-linked via ferric ions (Fe(3+)) and in which functional ingredients may be incorporated. By irradiation with (simulated) sunlight, the microspheres degrade, thereby releasing the encapsulated component(s). The degree of oxidation (DO) of the OKGM polymers could be well-controlled between 15 and 80%, as confirmed by proton titrations and FT-IR spectroscopy. OKGM of DO 80% was selected to prepare the microspheres because the high COO(-) content leads to a high density of cross-links, yielding a strong gel. The electrokinetic potential of the OKGM particles increases with increasing pH and decreasing salt concentration. Mössbauer and FT-IR spectroscopy revealed that the cross-links are formed through two modes of COO(-)-Fe(3+) coordination, that is, 68.4% by bridging and 31.6% by unidentate binding. Thus, the unique properties of the OKGM microspheres make them potentially applicable as light-controlled biocompatible delivery systems.
一种光响应递送系统已被开发出来。它由由TEMPO氧化的魔芋葡甘聚糖（OKGM）聚合物制成的凝胶微球组成，其中羧基（COO(-)）基团通过铁离子（Fe(3+)）交联，并且可以掺入功能成分。通过用（模拟）阳光照射，微球降解，从而释放封装的成分。如质子滴定和傅里叶变换红外光谱所证实的，OKGM聚合物的氧化度（DO）可以在15%至80%之间得到很好的控制。选择DO为80%的OKGM来制备微球，因为高COO(-)含量导致高密度的交联，产生强凝胶。OKGM颗粒的电动电位随着pH值的增加和盐浓度的降低而增加。穆斯堡尔谱和傅里叶变换红外光谱表明，交联是通过两种COO(-)-Fe(3+)配位模式形成的，即68.4%通过桥连和31.6%通过单齿结合。因此，OKGM微球的独特性质使其有可能作为光控生物相容性递送系统应用。
