Physicochemical characterization of chitosan nanoparticles:: electrokinetic and stability behavior
Physicochemical characterization of chitosan nanoparticles:: electrokinetic and stability behavior
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DOI：
10.1016/j.jcis.2004.08.186
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发表时间：
2005-03-15
影响因子：
9.9
通讯作者：
Bastos-González, D
中科院分区：
文献类型：
--
作者：
López-León, T;Carvalho, ELS;Bastos-González, D
研究了三聚磷酸钠（TPP）离子交联壳聚糖形成的纳米凝胶粒子的物理性质。电动性能和胶体稳定性进行了分析作为介质的pH值和离子强度的函数。壳聚糖颗粒表现出体积相变（溶胀/收缩过程）时，介质的物理化学条件发生变化。实验数据主要通过电泳迁移率测量和光子相关光谱和静态光散射技术获得。壳聚糖链具有葡糖胺基团，如果pH增加，葡糖胺基团可以被去质子化。因此，修改pH值从酸性到碱性值引起的消胀过程的基础上减少的分子内的电排斥内的颗粒网格。电泳迁移率数据有助于证实上述电机制负责的大小变化。此外，在壳聚糖-TPP颗粒的等电点附近的那些pH值下，系统变得胶体不稳定。离子强度的变化也引起了重要的结构变化。在这种情况下，低浓度和中等浓度的KCl的存在会引起肿胀，由于壳聚糖-TPP离子相互作用较弱，导致颗粒迅速崩解。这些最后的结果与部分电离网络中盐的凝胶溶胀理论的预测吻合得很好。(C)2004爱思唯尔公司All rights reserved.
Some physical properties of nanogel particles formed by chitosan ionically cross-linked by tripolyphosphate (TPP) have been studied. Electrokinetic properties and colloidal stability were analyzed as a function of pH and ionic strength of the medium. Chitosan particles showed volume phase transitions (swelling/shrinking processes) when the physicochemical conditions of the medium were changed. Experimental data were mainly obtained by electrophoretic mobility measurements and by photon correlation spectroscopy and static light scattering techniques. Chitosan chains possess glucosamine groups that can be deprotonated if the pH increases. Therefore, modification of pH from acid to basic values caused a deswelling process based on a reduction of the intramolecular electric repulsions inside the particle mesh. Electrophoretic mobility data helped to corroborate the above electrical mechanism as responsible for the size changes. Additionally, at those pH values around the isoelectric point of the chitosan-TPP particles, the system became colloidally unstable. Ionic strength variations also induced important structural changes. In this case, the presence of KCl at low and moderate concentrations provoked swelling, which rapidly turned on particle disintegration due to the weakness of chitosan-TPP ionic interactions. These last results were in good agreement with the predictions of gel swelling theory by salt in partially ionized networks. (C) 2004 Elsevier Inc. All rights reserved.