Interaction Pathways and Structure-Chemical Transformations of Alginate Gels in Physiological Environments
Language English Country United States Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
- MeSH
- Alginates chemistry pharmacology MeSH
- Biocompatible Materials chemistry pharmacology MeSH
- Cellular Microenvironment drug effects MeSH
- Gels chemistry pharmacology MeSH
- Metals chemistry MeSH
- Humans MeSH
- Magnetic Resonance Spectroscopy MeSH
- Cross-Linking Reagents chemistry pharmacology MeSH
- Hydrogen Bonding drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Alginates MeSH
- Biocompatible Materials MeSH
- Gels MeSH
- Metals MeSH
- Cross-Linking Reagents MeSH
The remarkably diverse affinity of alginate (ALG) macromolecules for polyvalent metal ions makes cross-linked alginate gels an outstanding biomaterial. Surprisingly, however, very little is known about their interactions and structural transformations in physiological environments. To bridge this gap, we prepared a set of ALG gels cross-linked by various ions and monitored their structural changes at different media simulating gastric and intestinal fluids and cellular environments. For these studies, we used multinuclear solid-state NMR (ss-NMR) spectroscopy, which revealed a range of competitive ion-exchange and interconversion reactions, the rate of which strongly depended on the nature of the cross-linking metal ions. Depending on the environment, ALG chains adopted different forms, such as acidic (hydro)gels stabilized by strong hydrogen bonds, and/or weakly cross-linked Na/H-gels. Simultaneously, the exchanged polyvalent ions extensively interacted with the environment even forming in some cases insoluble phosphate microdomains directly deposited in the ALG bead matrix. The extent of the transformations and incorporation of secondary phases into the alginate beads followed the size and electronegativity of the cross-linking ions. Overall, the applied combination of various macroscopic and biological tests with multinuclear ss-NMR revealed a complex pathway of alginate beads transformations in physiological environments.
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