Methods of loading and releasing low molecular weight cationic molecules in weak polyelectrolyte multilayer films
Methods of loading and releasing low molecular weight cationic molecules in weak polyelectrolyte multilayer films
复制标题
DOI：
10.1021/la010873m
复制
发表时间：
2002-02-19
期刊：
影响因子：
3.9
通讯作者：
Rubner, MF
中科院分区：
文献类型：
--
作者：
Chung, AJ;Rubner, MF
以亚甲基蓝染料为指示剂，研究了聚丙烯酸（PAA）和聚烯丙胺盐酸盐（PAH）多层膜的载药量和释放行为。PAA/PAH多层组装在pH = 2.5/2.5加载MB整个多层由于可用的结合位点和可渗透的结构。MB的负载量随膜厚度的增加而线性增加。使用缓冲的MB溶液能够更快和更均匀地将MB加载到多层中，因为MB溶液内的离子引起多层膜的进一步溶胀。释放研究表明，pH敏感的释放机制，其中较低的pH环境增加释放速率。缓冲环境也增加了MB从多层膜的释放速率。通过在2.5/2.5 PAA/PAH多层膜顶部组装pH 6.5/6.5的PAA/PAH的帽层，在非缓冲条件下更好地控制MB通过多层膜的扩散。然而，在缓冲条件下，6.5/6.5 PAA/PAH封端层的渗透性由于溶胀而增加，并且MB扩散不受阻碍。需要做进一步的工作来减缓缓冲条件下MB的释放。本文所展示的弱亲水性多层膜的可控负载能力和pH敏感性释放行为可能对药物递送应用有用。
This work studied the loading capabilities and release behavior of poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) multilayer films, using methylene blue dye (MB) as an indicator. PAA/PAH multilayers assembled at pH = 2.5/2.5 loaded MB throughout the multilayers due to available binding sites and a permeable structure. The amount of MB loaded increased linearly with increasing film thickness. Use of buffered MB solutions enabled faster and more uniform MB loading into the multilayers, because ions within the MB solution caused further swelling of the multilayer film. Release studies demonstrated a pH-sensitive release mechanism, where lower pH environments increased the release rate. Buffered environments also increased the release rate of MB from the multilayer films. By assembling capping layers of PAA/PAH at pH 6.5/6.5 on top of 2.5/2.5 PAA/PAH multilayers, the diffusion of MB through the multilayers was better controlled under nonbuffered conditions. Under buffered conditions, however, the permeability of the 6.5/6.5 PAA/PAH capping layers increased due to swelling, and MB diffusion was not hindered. Further work needs to be done to slow release of MB under buffered conditions. The controlled loading capabilities and pH-sensitive release behavior of weak polyelectrolyte multilayer films demonstrated here may be useful toward drug delivery applications.