Xie Yu-Liang, Wang Ming-Jun, Yao Shan-Jing
Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, PR China.
Langmuir. 2009 Aug 18;25(16):8999-9005. doi: 10.1021/la9014338.
A novel microcapsule system composed of sodium cellulose sulfate (NaCS) and chitosan was prepared by layer-by-layer (LbL) self-assembly technique. As a potential drug delivery system, it had several advantages in biocompatibility and biodegradation due to its use of natural polysaccharides. Some parameters in the preparation of the microcapsule, such as layers in the LbL process (up to 20 layers), chitosan viscosities (50, 100, and 200 mPas), outmost layer materials (NaCS or chitosan), and NaCl concentrations (0 M, 0.5 M, 1 M), were investigated to better understand their effects on the LbL process. A novel method for removing the core templates PLA and CaCO3 from the formed core-shell structure was proposed by addition of N-methyl pyrrolidone or EDTA-Na. This preparation process was well observed by a microscope-camera system. The hollow microcapsules were tested by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and scanning probe microscopy (SPM) to characterize their size, morphology, and surface. The results showed that the shell thickness of microcapsules was about 6 nm, and the average thickness of one layer of NaCS/chitosan polyelectrolyte complex was 1.5 nm. The molecular weight cutoff in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed about 70 kDa by using of diffusion test with the cell lysate of Escherichia coli.
通过层层自组装技术制备了一种由硫酸纤维素钠（NaCS）和壳聚糖组成的新型微胶囊系统。作为一种潜在的药物递送系统，由于其使用天然多糖，在生物相容性和生物降解性方面具有若干优势。研究了微胶囊制备过程中的一些参数，如层层过程中的层数（最多20层）、壳聚糖粘度（50、100和200 mPas）、最外层材料（NaCS或壳聚糖）以及NaCl浓度（0 M、0.5 M、1 M），以更好地了解它们对层层过程的影响。通过添加N-甲基吡咯烷酮或EDTA-Na，提出了一种从形成的核壳结构中去除核心模板聚乳酸（PLA）和碳酸钙（CaCO₃）的新方法。通过显微镜-相机系统对该制备过程进行了良好的观察。通过扫描电子显微镜（SEM）、共聚焦激光扫描显微镜（CLSM）和扫描探针显微镜（SPM）对中空微胶囊进行测试，以表征其尺寸、形态和表面。结果表明，微胶囊的壳厚度约为6 nm，一层NaCS/壳聚糖聚电解质复合物的平均厚度为1.5 nm。使用大肠杆菌细胞裂解物进行扩散试验，十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）中的截留分子量显示约为70 kDa。
