Impact of Glucose on the Nanostructure and Mechanical Properties of Calcium-Alginate Hydrogels
Journal article, 2022

Alginate is a polysaccharide obtained from brown seaweed that is widely used in food, pharmaceutical, and biotechnological applications due to its versatility as a viscosifier and gelling agent. Here, we investigated the influence of the addition of glucose on the structure and mechanical properties of alginate solutions and calcium-alginate hydrogels produced by internal gelation through crosslinking with Ca2+ . Using1H low-field nuclear magnetic resonance (NMR) and small angle neutron scattering (SANS), we showed that alginate solutions at 1 wt % present structural hetero-geneities at local scale whose size increases with glucose concentration (15–45 wt %). Remarkably, the molecular conformation of alginate in the gels obtained from internal gelation by Ca2+ crosslinking is similar to that found in solution. The mechanical properties of the gels evidence an increase in gel strength and elasticity upon the addition of glucose. The fitting of mechanical properties to a poroelastic model shows that structural changes within solutions prior to gelation and the increase in solvent viscosity contribute to the gel strength. The nanostructure of the gels (at local scale, i.e., up to few hundreds of Å) remains unaltered by the presence of glucose up to 30 wt %. At 45 wt %, the permeability obtained by the poroelastic model decreases, and the Young’s modulus increases. We suggest that macro (rather than micro) structural changes lead to this behavior due to the creation of a network of denser zones of chains at 45 wt % glucose. Our study paves the way for the design of calcium-alginate hydrogels with controlled structure for food and pharmaceutical applications in which interactions with glucose are of relevance.

Alginate

Glucose

Poroelasticity

Hydrogels

Crosslinking

Mechanical properties

SANS

Structure

Author

Patricia Lopez-Sanchez

Chalmers, Biology and Biological Engineering, Food and Nutrition Science

Ali Assifaoui

University of Burgundy - Franche-Comté

Fabrice Cousin

University Paris-Saclay

Josefine Moser

RISE Research Institutes of Sweden

Mauricio R. Bonilla

Basque Center for Applied Mathematics (BCAM)

Anna Ström

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Gels

23102861 (eISSN)

Vol. 8 2 71

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Subject Categories

Physical Chemistry

Polymer Technologies

Other Materials Engineering

DOI

10.3390/gels8020071

PubMed

35200453

More information

Latest update

1/3/2024 9