Thu B, Bruheim P, Espevik T, Smidsrød O, Soon-Shiong P, Skjåk-Braek G
Department of Biotechnology, Norwegian Institute of Technology, University of Trondheim, Norway.
Biomaterials. 1996 May;17(10):1031-40. doi: 10.1016/0142-9612(96)84680-1.
The interactions between alginate and polycations have been studied by using different labelling techniques. Binding of poly-L-lysine (PLL) to alginate in the gel state is mainly governed by the amount of dissociable negative charges on the bead surface. PLL was found to bind more rapidly to gel beads made from alginate with a high content of mannuronic acid. The binding was enhanced by increasing the alginate concentration on the surface by making inhomogeneous beads. When the capsules were stored in the presence of cations with high affinity for alginate (Ca2+, Sr2+), PLL was washed off. Less PLL is bound to strontium alginate than to calcium alginate beads. Two mechanisms appear to be responsible for the binding of sodium alginate to alginate PLL capsules (coating): (i) an electrostatic interaction between the soluble coating material and excess positive charges on PLL on the surface; (ii) the formation of a calcium alginate gel on the surface owing to leaching of calcium ions from the core. The stability and efficiency of the coating as a function of molecular size and sequential structure of the coating polymer have also been investigated.
通过使用不同的标记技术研究了藻酸盐与聚阳离子之间的相互作用。聚-L-赖氨酸（PLL）与凝胶态藻酸盐的结合主要受珠粒表面可解离负电荷数量的控制。发现PLL与由富含甘露糖醛酸的藻酸盐制成的凝胶珠粒结合得更快。通过制备不均匀珠粒增加表面藻酸盐浓度可增强结合。当胶囊在对藻酸盐具有高亲和力的阳离子（Ca2+、Sr2+）存在下储存时，PLL会被洗脱。与钙藻酸盐珠粒相比，PLL与锶藻酸盐的结合较少。藻酸钠与藻酸盐-PLL胶囊（包衣）的结合似乎有两种机制：（i）可溶性包衣材料与表面PLL上多余正电荷之间的静电相互作用；（ii）由于钙离子从核心沥出，在表面形成钙藻酸盐凝胶。还研究了包衣的稳定性和效率与包衣聚合物分子大小和序列结构的关系。
