Lorén Niklas, Shtykova Liubov, Kidman Siw, Jarvoll Patrik, Nydén Magnus, Hermansson Anne-Marie
SIK, The Swedish Institute for Food and Biotechnology, P.O. Box 5401, SE-402 29 Göteborg, Sweden.
Biomacromolecules. 2009 Feb 9;10(2):275-84. doi: 10.1021/bm801013x.
The effect of the kappa-carrageenan concentration on gel microstructure and self-diffusion of polyamideamine dendrimers has been determined by transmission electron microscopy (TEM), image analysis, and nuclear magnetic resonance (NMR) diffusometry. Different salt conditions of KCl, NaCl, and mixtures thereof allowed for formation of significantly different microstructures. The kappa-carrageenan concentrations were varied between 0.25 and 3.0 w/w% for a salt mixture containing 20 mM KCl and 200 mM NaCl gels and between 0.5 and 4.0 w/w% for 250 mM NaCl gels. Furthermore, the effect of potassium ion concentration on the gel structure and the dendrimer diffusion rate was determined. The potassium ion concentration was varied between 20 mM KCl and 200 mM KCl. Two different dendrimer generations with significant difference in size were used: G2 and G6. Dendrimers were found to be sensitive probes for determination of the effect of the gel microstructure on molecular diffusion rate. A qualitative comparison between TEM micrographs, NMR diffusometry data and image analysis showed that the gel structure has a large impact on the dendrimers diffusion in kappa-carrageenan gels. It was found that diffusion was strongly influenced by the kappa-carrageenan concentration and the dendrimer generation. Small voids in the gel network gave strongly reduced diffusion. Image analysis revealed that the interfacial area between the gel network and the surrounding water phase correlated well with the dendrimer diffusion.
通过透射电子显微镜（TEM）、图像分析和核磁共振（NMR）扩散测定法，确定了κ-卡拉胶浓度对聚酰胺胺树枝状大分子凝胶微观结构和自扩散的影响。KCl、NaCl及其混合物的不同盐条件导致形成显著不同的微观结构。对于含有20 mM KCl和200 mM NaCl凝胶的盐混合物，κ-卡拉胶浓度在0.25至3.0 w/w%之间变化；对于250 mM NaCl凝胶，κ-卡拉胶浓度在0.5至4.0 w/w%之间变化。此外，还确定了钾离子浓度对凝胶结构和树枝状大分子扩散速率的影响。钾离子浓度在20 mM KCl至200 mM KCl之间变化。使用了两种尺寸差异显著的不同树枝状大分子代数：G2和G6。发现树枝状大分子是用于确定凝胶微观结构对分子扩散速率影响的灵敏探针。TEM显微照片、NMR扩散测定数据和图像分析之间的定性比较表明，凝胶结构对树枝状大分子在κ-卡拉胶凝胶中的扩散有很大影响。发现扩散受到κ-卡拉胶浓度和树枝状大分子代数的强烈影响。凝胶网络中的小空隙使扩散大大降低。图像分析表明，凝胶网络与周围水相之间的界面面积与树枝状大分子扩散密切相关。
