Preparation of dendrimer-loaded microcapsules by a layer-by-layer deposition of polyelectrolytes
Preparation of dendrimer-loaded microcapsules by a layer-by-layer deposition of polyelectrolytes
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DOI：
10.1016/j.msec.2009.03.019
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发表时间：
2009-08
期刊：
影响因子：
--
通讯作者：
S. Tomita;Katsuhiko Sato;J. Anzai
中科院分区：
文献类型：
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作者：
S. Tomita;Katsuhiko Sato;J. Anzai
采用聚烯丙基胺盐酸盐和聚乙烯基硫酸酯在含有聚酰胺-胺树枝状大分子的碳酸钙（CaCO 3）微粒表面逐层沉积的方法，制备了以CaCO 3为核心的聚酰胺-胺树枝状大分子微胶囊。荧光光谱分析表明，三甲基罗丹明标记的荧光树枝状大分子被成功地封装在微胶囊中。在pH 4.0时，树枝状聚合物从微胶囊中的泄漏可以忽略不计，而在pH 7.0和9.0的介质中，分别在6 h后释放7%和25%的树枝状聚合物。以孟加拉玫瑰红（RB）和1-苯胺基萘-8-磺酸（ANS）两种有机染料为染料，考察了载药微胶囊的结合和释放性能。RB被容纳在微胶囊中，并在pH 8.0的缓冲溶液中迅速释放，而在pH 7.0的释放受到抑制，可能是由于RB与胶囊中的树枝状大分子结合。ANS的荧光发射在负载树枝状聚合物的微胶囊的存在下被高度增强，这表明ANS与树枝状聚合物在微胶囊中的成功结合，因为荧光强度在不含树枝状聚合物的微胶囊的存在下没有增强。动力学研究表明，在树枝状聚合物负载的微胶囊中的ANS的摄取速率由ANS穿过胶囊壁的运输速率决定。另一方面，ANS从PAMAM的解离是ANS从微囊释放的速率决定步骤。
Poly(amidoamine) dendrimer-loaded microcapsules were prepared by a layer-by-layer deposition of poly(allylamine hydrochloride) and poly(vinyl sulfate) on the surface of calcium carbonate (CaCO3) microparticles that contain poly(amidoamine) dendrimer, followed by dissolution of CaCO3core. A fluorescence spectroscopy revealed that a fluorescent dendrimer labeled with trimethylrhodamine is successfully encapsulated in the microcapsules. The leakage of the dendrimer out of the microcapsule was negligible at pH 4.0, while 7% and 25% of dendrimer were released after 6 h in the media at pH 7.0 and 9.0, respectively. The binding and release properties of the dendrimer-loaded microcapsules were evaluated using two kinds of organic dyes Rose Bengal (RB) and 1-anilinonaphthalene-8-sulfonic acid (ANS). RB was accommodated in the microcapsules and released rapidly into buffer solution at pH 8.0, while the release was suppressed at pH 7.0 probably due to binding of RB to dendrimer in the capsules. A fluorescence emission of ANS was highly enhanced in the presence of dendrimer-loaded microcapsules, suggesting a successful binding of ANS to dendrimer in the microcapsules because the fluorescence intensity was not enhanced in the presence of dendrimer-free microcapsules. The kinetic studies revealed that the rate of uptake of ANS in the dendrimer-loaded microcapsules was determined by the rate of transport of ANS across the capsule wall. On the other hand, the dissociation of ANS from PAMAM is the rate-determining step for the release of ANS from the microcapsules.