葡聚糖水凝胶微球的制备与表征

Synthesis and characterization of hydrogel microparticles based on dextran

采用反相微乳液交联法,以葡聚糖天然高分子为原料,制备了一系列基于葡聚糖的水凝胶微球。葡聚糖通过高碘酸钠氧化进行醛基化修饰,进一步与乙二胺发生还原胺化反应进行交联;交联反应在以失水山梨酸酯类(Span 80/Tween 80)表面活性剂复配体系作为乳化剂、环己烷为油相构成的油包水型反相微乳液中进行。表面活性剂复配体系的组分配比是影响该葡聚糖水凝胶微球的粒径及形貌的重要因素,研究结果表明,随着表面活性剂复配体系的亲水亲油平衡值(HLB value)增加,微球粒径呈现先减小而后增大并基本保持不变的趋势;当该复配表面活性剂的HLB=5.27(即,m(Tween 80)/m(Span 80)=10)时,获得的葡聚糖凝胶微球粒径最小且平均粒径为(21.6±1.65)μm,粒径分布在15~28μm之间。

Microgels based on dextran were prepared by the inverse microemulsion cross-linking technique using Span 80/Tween 80 as mixed-surfactants and cyclohexane as the continuous phase. These hydrogel particles were formed in the water-in-oil （W/O） mieroemulsion system via the reductive amination reaction between the oxidized dextran （Dex-CHO） and ethylenediamine at room temperature. Effect of the composition of the mixed emulsifier （or HLB value） on the size of the microgels was studied. SEM and DLS measurement showed that the particle size of the resulted microgel was controllable by modulating the composition of the mixed-surfactants （HLB value）. When HLB value increased, the particle size of the resulted mierogel decreased firstly, then increased, and maintain constantly at last. Dextran-based microgels synthesized using the mixed-surfactant of Span 80/Tween 80 were obviously smaller than that prepared with Span 80. And, dextran microgel with a relatively small diameter of （21.60±1.65） μm and particle size distribution between 15 and 28 μm was prepared as the HLB=5.27 （m（Tween 80）/m（Span 80）=10）.