Acid-Labile Polyvinylamine Micro- and Nanogel Capsules.
Acid-Labile Polyvinylamine Micro- and Nanogel Capsules.
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DOI：
10.1021/ma070443o
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发表时间：
2007-06
期刊：
影响因子：
5.5
通讯作者：
Lianjun Shi;C. Berkland
中科院分区：
文献类型：
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作者：
Lianjun Shi;C. Berkland
中空纳米颗粒代表了有效成分封装的新兴发展领域。扩大这些纳米材料的能力将需要继续努力填充诸如尺寸控制，生物降解性和环境响应性等特性。采用自由基聚合的方法在纳米二氧化硅表面制备了耐酸聚n -乙烯基甲酰胺（PNVF）纳米胶囊。在含有酸不稳定的缩醛的新型交联剂存在下的聚合促进了氢氧化钠对二氧化硅纳米颗粒模板的稳定蚀刻和可降解PNVF纳米胶囊的回收。PNVF的甲酰胺侧基通过长时间暴露于氢氧化钠水解得到聚乙烯胺（PVAm）微胶囊和纳米胶囊。随着pH值的降低，两种胶囊类型的溶出率均有所增加。此外，PVAm纳米胶囊的膨胀与PVAm网络的相对电荷密度成正比（甲酰胺水解程度和pH的函数），可能是由于弹性壳网络中带正电的氨基的排斥。所报道的合成方法提供了赋予纳米胶囊关键属性的方法，如尺寸控制、pH敏感降解、pH响应肿胀和胺功能。
Hollow nanoparticles represent an emerging area of development for the encapsulation of active ingredients. Expanding the capabilities of these nanomaterials will require continued efforts to infill properties such as size control, biodegradability, and environmental responsiveness. Acid-labile poly(N-vinylformamide) (PNVF) nanocapsules were synthesized by free radical polymerization of N-vinylformamide on the surface of silica nanoparticles. Polymerization in the presence of a novel crosslinker that contains an acid-labile ketal facilitated stable etching of silica nanoparticle templates using sodium hydroxide and recovery of degradable PNVF nanocapsules. The formamido side group of PNVF was then hydrolyzed by extended exposure to sodium hydroxide to produce polyvinylamine (PVAm) micro- and nanocapsules. Both capsule types demonstrated an increasing dissolution rate as pH decreased. In addition, PVAm nanocapsules exhibited swelling in proportion to the relative charge density of the PVAm network (a function of the degree of formamide hydrolysis and pH), presumably due to the repulsion of positively charged amino groups within the elastic shell network. The synthetic approaches reported provide methods to endow nanocapsules with key attributes such as size control, pH sensitive degradation, swelling in response to pH, and amine functionality.