壳聚糖-脱氧胆酸及其叶酸偶联体的表征及自组装特性研究

Comparison of chitosan-deoxycholic acid self-aggregated nanoparticles and its folic acid coupler

以1-乙基-(3-二甲基氨基丙基)碳酰二亚胺(EDC)为催化剂,将脱氧胆酸接枝到壳聚糖主链的氨基上,得到疏水改性的双亲性壳聚糖;再将叶酸连接于壳聚糖氨基,可得到具有肿瘤靶向潜力的双亲性共聚物。利用红外光谱1、H核磁、X射线晶体衍射图谱对其结构进行表征。脱氧胆酸-壳聚糖、叶酸-壳聚糖-脱氧胆酸在水相中通过透析处理均能形成自聚集体,利用荧光探针技术研究其自聚集行为。制得的两种自聚集体均具有较低的临界胶束浓度(10-2mg/ml),透射电镜和粒径分析测试显示制得的自聚集体为纳米级颗粒。随着脱氧胆酸取代度的增加,粒径降低,临界胶束浓度下降,但叶酸直接偶联壳聚糖导致自组装阻力增加。

Deoxycholic acid-modified chitosan（CS-DA） were synthesized by coupling Deoxycholic acid to the amino groups of chitosan with EDC as catalyzer. Then folic acid was coupled to the amino groups of chitosan which has tumor targeted potential. The structure of CS-DA and FA-CS-DA was characterized by FT-IR, ^1H NMR and XRD. Both of them formed self-aggregated nanoparticles in physiological saline and the self-aggregated behavior were studied by fluorescence probe technique. The self-aggregates had low critical aggregate concentration（CAC）about 10^-2mg/ml. The measurements of transmission electron microscope（TEM） and dynamic light scattering（DLS） indicated that the self-aggregates were nanoparticles. CAC and particle size decreased with Deoxycholic acid substisute degree increased. But it is a hindrance to self- aggregate because of folic acid conjugate to chitosan directly.