Biophysics and Medical Technology, Department of Physics, The Norwegian University of Science and Technology, NTNU, NO-7491 Trondheim, Norway.
Department of Biotechnology, The Norwegian University of Science and Technology, NTNU, NO-7491 Trondheim, Norway.
Carbohydr Polym. 2015 Nov 20;133:126-34. doi: 10.1016/j.carbpol.2015.07.004. Epub 2015 Jul 13.
Alginates form gels in the presence of various divalent ions, such as Ca(2+) that mediate lateral association of chain segments. Various procedures exist that introduce Ca(2+) to yield alginate hydrogels with overall homogeneous or controlled gradients in the concentration profiles. In the present study, the effect of adding oligomers of α-l-guluronic acid (oligoGs) to gelling solutions of alginate was investigated by determination of the cluster growth stimulated by in situ release of Ca(2+). Three different alginate samples varying in fraction of α-l-guluronic acid and molecular weights were employed. The cluster growth was determined for both pure alginates and alginates with two different concentrations of the oligoGs employing dynamic light scattering. The results show that addition of oligoG slows down the cluster growth, the more efficient for the alginates with higher fraction of α-l-guluronic acid, and the higher molecular weight. The efficiency in delaying and slowing the cluster growth induced by added oligoG were discussed in view of the molecular parameters of the alginates. These results show that oligoG can be added to alginate solutions to control the cluster growth and eventually also transition to the gel state. Quantitative relation between the concentration of added oligoG, type and molecular weight of the alginate, and concentration, can be employed as guidelines in tuning alginate cluster growth with specific properties.
藻酸盐在各种二价离子（如 Ca(2+)）的存在下形成凝胶，这些离子介导链段的侧向缔合。存在各种将 Ca(2+)引入以产生藻酸盐水凝胶的方法，这些水凝胶在浓度分布上具有整体均匀或受控的梯度。在本研究中，通过测定原位释放 Ca(2+)刺激的团簇生长，研究了向藻酸盐凝胶溶液中添加 α-l-古洛糖醛酸低聚物（寡糖 Gs）的影响。使用了三种不同的藻酸盐样品，其 α-l-古洛糖醛酸的分数和分子量不同。使用动态光散射法测定了纯藻酸盐和两种不同浓度寡糖 Gs 的藻酸盐的团簇生长。结果表明，添加寡糖 G 会减缓团簇生长，对于 α-l-古洛糖醛酸分数较高和分子量较高的藻酸盐更为有效。根据藻酸盐的分子参数讨论了添加寡糖 G 延迟和减缓团簇生长的效率。这些结果表明，可以向藻酸盐溶液中添加寡糖 G 来控制团簇生长，并最终也过渡到凝胶状态。添加的寡糖 G 的浓度、藻酸盐的类型和分子量以及浓度之间的定量关系，可以作为调整具有特定性质的藻酸盐团簇生长的指南。
