Modified Gellan Gum hydrogels with tunable physical and mechanical properties

Abstract

Gellan Gum (GG) has been recently proposed for tissue engineering applications. GG hydrogels are produced by physical crosslinking methods induced by temperature variation or by the presence of divalent cations. However, physical crosslinking methods may yield hydrogels that become weaker in physiological conditions due to the exchange of divalent cations by monovalent ones. Hence, this work presents a new class of GG hydrogels crosslinkable by both physical and chemical mechanisms. Methacrylate groups were incorporated in the GG chain, leading to the production of a methacrylated gellan gum (MeGG) hydrogel with highly tunable physical and mechanical properties. The chemical modification was confirmed by proton nuclear magnetic resonance ( 1 H-NMR) and Fourier transform infrared spectroscopy (FTIR-ATR). The mechanical properties of the developed hydrogel networks, with Young's modulus values between 0.15 and 148 kPa, showed to be tuned by the different crosslinking mechanisms used. The in vitro swelling kinetics and hydrolytic degradation rate was dependent on the crosslinking mechanisms used to form the hydrogels. Three-dimensional (3D) encapsulation of NIH-3T3 fibroblast cells in MeGG networks demonstrated in vitro biocompatibility

Shear strength behavior and parameters of microbial gellan gum-treated soils: from sand to clay

“…Gellan gum exhibits poor solubility at low temperature, while sufficient gum dissolution with random coil conformation forms uniform gellan gum solutions at temperatures higher than 90°C [39]. Upon temperature decrease, randomly dispersed gellan gum coils adopt a double-helical structure through ionotropic sol-gel transition, which results in high viscous and firm gellan gum gel formation [26,61]. Details of the gellan gum rheology and a case study of experimental implementations can be found in Chang et al [17,22].…”

Modified gellan gum hydrogels for tissue engineering applications

“…Other work using methacrylated LAGG has shown that the degradation rate (in 0.1 mM NaOH, at 37 °C) can be influenced by the cross-linking 90 mechanism, i.e. physical or combined physical and chemical 58 .…”

“…Other strategies involve methacrylation of the GG chain (Fig. 1C) followed by physical and/or chemical 65 cross-linking 58 . These approaches can be used to tune the elastic modulus of GG hydrogels to that comparable with a wide range of human soft tissues such as muscle, liver and cartilage 59 .…”

Tissue engineering with gellan gum

“…Such UV cross-linking approaches were recently highlighted as a promising means of accurately controlling bioprinted scaffolds 123 . Although methacrylated gelatin has been the principal material applied for this purpose to date 136,137 , the methacrylated gellan gums that have so far been photopolymerised whilst confined in a casting mould 37,63,104 could be readily applied in UV-bioprinting. Extending MA-GG into the field of UV-bioprinting presents a new mode of GG biofabrication with significant future potential.…”