Physicochemical and Rheological Characterization of Different Low Molecular Weight Gellan Gum Products and Derived Ionotropic Crosslinked Hydrogels

Abstract

A series of four different low molecular weight gellan gum products was obtained by alkaline hydrolysis with the aim to investigate the impact of the molecular weight on the rheological properties of the polysaccharide aqueous dispersions and on the physicochemical characteristics of derived ionotropic crosslinked hydrogels. In particular, thermo-rheological analysis was conducted on aqueous dispersions to study the influence of molecular weight on the thermogelation properties typical of the native polysaccharide while strain sweep experiments were conducted to establish if aqueous dispersion shows a viscoelastic behavior. The effect of different Ca2+ on the rheological properties of hydrogels were studied. Furthermore, ionotropic crosslinked hydrogels were analyzed in terms of morphology on the dried state and swelling behavior, while their viscoelastic properties were studied by means of rheological analysis conducted in frequency sweep regime after different time points of incubation in phosphate buffer at pH 7.4. Release experiments conducted using fluorescein isothiocyanate labelled dextran as a model diffusion agent and was performed to investigate the possibility of using the low molecular weight GG-derived hydrogels as an active molecule-releasing device. Finally, the cytocompatibility of hydrolysis products was investigated, as well as the capacity of hydrogels to encapsulate viable MC3T3-E1 preosteoblastic cells.

Bioactive Scaffolds Based on Amine-Functionalized Gellan Gum for the Osteogenic Differentiation of Gingival Mesenchymal Stem Cells

“…37 The thermotropic gelation of GG depends on several factors such as polysaccharide molecular weight and concentration, as well as the presence of cations and the degree of cross-linking. 38 Interestingly, as DD EDA% increases, the more considerable is the perturbation on the coil to helix transition, up to an almost totally temperature independence of the moduli in the analyzed range for GG-EDA 0.5 and 1 (Figure 2c). At higher concentrations, the G′ values became similar regardless of the derivatization degree.…”

“…In particular, GG goes through a thermally reversible coil-to-helix transition as the temperature decreases . The thermotropic gelation of GG depends on several factors such as polysaccharide molecular weight and concentration, as well as the presence of cations and the degree of cross-linking …”

Ionotropic Gelation and Chemical Crosslinking as Methods for Fabrication of Modified-Release Gellan Gum-Based Drug Delivery Systems

“…The process takes place mostly after decreasing the temperature. The combination of these helices leads to the formation of a double helix and then to a gel network [ 44 , 45 ].…”

Comparative Large Amplitude Oscillatory Shear (LAOS) Study of Ionically and Physically Crosslinked Hydrogels

“…Over the last decades, several combinations of either polysaccharides or proteins, or even polysaccharides with proteins (including inevitable gelatin), have been utilized to obtain the functionalized mechanical properties of hydrogels [ 1 , 2 , 9 , 10 , 11 , 12 , 13 , 14 ]. Moreover, the mechanical characterization of such hydrocolloid aqueous solutions, and the resulting gels, are studied beyond the LVE, including large-amplitude oscillatory shear (LAOS), among other methods [ 6 , 9 , 10 , 11 , 12 , 13 , 14 ]. When investigating binary gelatin-alginate systems for in situ gelation and ex situ individual gel layers, Goudoulas and Germann [ 9 ] reported comparable storage modulus G’ overshoots for the in situ gelation samples.…”