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Partially degalactosylated xyloglucan from tamarind seeds (Deg-XG) is a very appealing biopolymer for the production of in situ gelling systems at physiological temperature. In this work, we observe that the morphology of hydrogels evolves towards high degrees of structural organization with time, yielding to dense stacks of thin membranes within 24h of incubation at 37°C. We also explore the possibility offered by gamma irradiation of controlling the time scale of this phenomenon, the final morphology and mechanical properties of the system. Structural and molecular modifications of Deg-XG with dose are investigated by FTIR, dynamic light scattering (DLS) and rotational viscosimetry. The impact on gelation ability and gel strength is studied by rheological analysis. The morphology evolution is investigated by SEM analysis, and absence of cytotoxicity verified by MTS assay and optical microscopy of neuroblastoma cells., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Abstract: The use of synergistic interactions between polysaccharides can represent an important approach for the preparation of physical networks with a wide range of industrial applications, such as in the food and biomedical fields. Locust Bean Gum and Xanthan, two biocompatible polymers, are able to form gels when mixed together. A detailed study was carried out on three samples, prepared at different weight ratios and two temperatures, by means of light scattering and rheological techniques. The solid-like character of each sample was evaluated by measurements of the viscoelastic spectrum and intensity autocorrelation function. The contribution of fast and slow fluctuations to the static light scattered intensity was also evaluated at different angles. The power law exponents for the sol–gel transitions were estimated together with the fractal dimensions. The scattering results were found in good agreement with the mechanical ones in revealing a strong dependence of the structural properties of the different samples on their preparation conditions. Indeed, results show that a fine tuning of the properties of the mixed gels is possible through the change of the temperature preparation and/or the polymer weight ratio. [ABSTRACT FROM AUTHOR]

Polymeric hydrogels are increasingly considered as scaffolds for tissue engineering due to their extraordinary resemblance with the extracellular matrix (ECM) of many tissues. As cell adhesion is a key factor in regulating important cell functions, hydrogel scaffolds are often functionalized or loaded with a variety of bioactive molecules that can promote adhesion. Interesting biomimetic approaches exploit the properties of mussel-inspired recombinant adhesive proteins. In this work, we prepared hydrogel scaffolds with a 50%w mixture of k-carrageenan (kC) and polyvinyl alcohol (PVA), by a two-step physical gelation process, and we coated them with Perna viridis foot protein-5β (Pvfp5β). The mechanical and morphological properties of hydrogels were investigated both after conditioning with typical cell culture media and also after coating with the Pvfp5β. The protein resulted strongly adsorbed onto the surface of the hydrogel and also able to penetrate in its interiors to a certain depth, mainly interacting with the kC component of the scaffold as resulted from the confocal analysis. Mouse embryonic fibroblasts NIH-3T3 were seeded on top of the hydrogels and cultured up to two weeks. The role of Pvfp5β in promoting cell adhesion, spreading and colonization of the scaffold was demonstrated. [ABSTRACT FROM AUTHOR]