Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India.
Colloids Surf B Biointerfaces. 2013 Jan 1;101:487-92. doi: 10.1016/j.colsurfb.2012.07.025. Epub 2012 Jul 24.
Stable hollow microcapsules composed of sodium carboxymethyl cellulose (CMC) and poly (allylamine hydrochloride) (PAH) were produced by layer-by-layer adsorption of polyelectrolytes onto CaCO(3) microparticles. Subsequently the core was removed by addition of chelating agents for calcium ions. Zeta potential studies showed charge reversal with deposition of successive polyelectrolyte layers, indicating that the alternate electrostatic adsorption of polyelectrolytes of opposite charge was successfully achieved. The size and surface morphology of the capsules was characterized by various microscopy techniques. The pH responsive loading behavior was elucidated by confocal laser scanning microscopy (CLSM) studies using fluorescence labeled dextran (FITC-dextran) and labeled BSA (FITC-BSA). CLSM images confirmed the open (pH≤6) and closed state (pH≥7) of the capsules. A model drug bovine serum albumin (BSA) was spontaneously loaded below its isoelectric point into hollow microcapsules, where BSA is positively charged. The loading of the BSA into the microcapsules was found to be dependent on the feeding concentration and pH of the medium. 65% of the loaded BSA was released over 7h of which about 34% was released in the first hour. These findings demonstrate that (CMC/PAH)(2) hollow capsules can be further exploited as a potential drug delivery system.
通过将聚电解质逐层吸附到碳酸钙微球上来制备由羧甲基纤维素钠（CMC）和聚烯丙基胺盐酸盐（PAH）组成的稳定的空心微胶囊。随后，通过添加钙螯合剂去除核心。zeta 电位研究表明，随着聚电解质层的连续沉积发生电荷反转，表明成功地实现了带相反电荷的聚电解质的交替静电吸附。通过各种显微镜技术对胶囊的大小和表面形态进行了表征。通过使用荧光标记的葡聚糖（FITC-葡聚糖）和标记的 BSA（FITC-BSA）的共焦激光扫描显微镜（CLSM）研究阐明了 pH 响应的负载行为。CLSM 图像证实了胶囊的开（pH≤6）和闭（pH≥7）状态。将牛血清白蛋白（BSA）作为模型药物在低于等电点的条件下自发加载到空心微胶囊中，其中 BSA 带正电荷。发现 BSA 的加载量取决于进料浓度和介质的 pH 值。在 7 小时内释放了 65%的加载 BSA，其中约 34%在第一个小时内释放。这些发现表明（CMC/PAH）（2）空心胶囊可以进一步开发为潜在的药物传递系统。
