Magnesium ions and alginate do form hydrogels: a rheological study

Abstract

Our study shows that magnesium ions which have so far been considered as non-gelling ions for alginate do induce alginate gelation. Rheology is used to examine effects of alginate chemical composition as well as alginate and magnesium ion concentration. Gelation in this system occurs at ca. 5-10 times higher concentration of ions than reported for calcium-based gels. Alginate network formation with magnesium ions is very slow and is typically accomplished within 2-3 hours. Gelation with magnesium ions is also strongly dependent on alginate chemical composition as the presence of long guluronic units privileges faster gel formation.

Mechanical properties of alginate hydrogels manufactured using external gelation

“…Topuz et al [18] reported that Mg 2+ does promote the gelation of alginate solutions, but the kinetics of gelation are much slower than for Ca 2+ and the resultant gels exhibited moduli <5 kPa. The samples produced using Mg 2+ in the work reported here were indistinguishable from the ungelled alginate solution upon performing indentation measurements.…”

“…Alginate hydrogels have been used in bone and cartilage tissue engineering [13][14], as vehicles for cell delivery, wound dressings, and as matrices to immobilise cells [15][16]. They are commonly formed via ionotropic gelation of dissolved alginate in the presence of multivalent cations such as Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ [17][18]. Delivery of the cations into the alginate solution is often performed using an emulsification method, leading to the production of alginate hydrogel beads; this is usually described as internal gelation [19][20].…”

Polymeric Supramolecular Hydrogels as Materials for Medicine

“…Groll and coworkers investigated the possibility to form alginate hydrogels with magnesium ions, supplementing a new alginate-based biomaterial [112]. For this purpose, different types of alginate were used, differing in the ratio of guluronic and mannuronic acid, in their respective block lengths, and in the composition of the blocks (plain guluronic, plain mannuronic, or alternating); the magnesium concentration was also varied, leading to a toolbox ranging from 0.5 to 8 wt% alginate concentration and ion concentrations of 10-400 mmol L −1 .…”

Quantum Chemical Studies of Potential Associates in Europium (III) Alginate Solutions

“…На сегодняшний день особый интерес пред-ставляют наработки в области производства аль-гинатных гелей для медицинского и биологиче-ского анализов [2][3][4]. В частности, их комплексы с редкоземельными элементами характеризуются способностью к люминесценции, что позволяет использовать их для визуализации средств достав-ки лекарственных препаратов к месту заражения при облучении УФ-светом [2].…”