Modified Gellan Gum hydrogels with tunable physical and mechanical properties.

TLDR: Three-dimensional encapsulation of NIH-3T3 fibroblast cells in MeGG networks demonstrated in vitro biocompatibility confirmed by high cell survival and the in vitro swelling kinetics and hydrolytic degradation rate were dependent on the crosslinking mechanisms used to form the hydrogels.

About: This article is published in Biomaterials.The article was published on 2010-10-01 and is currently open access. It has received 332 citations till now. The article focuses on the topics: Self-healing hydrogels & Gellan gum.

Figures

Fig. 5. Mechanical properties of GG and MeGG hydrogels: Young’s Modulus, Ultimate stress and Ultimate strain. The influence of three parameters over the mechanical properties of the hydrogels was evaluated: (A) Concentration of ions in the hydrogel fabrication; (B) Type of crosslinking mechanism (P, C or PC); and (C) Polymer concentration. The mechanical properties of the developed hydrogels showed to be highly dependent on the ionic content, type of crosslinking, methacrylation degree and polymer concentration. Statistical analysis through two-way ANOVA and Bonferroni post-hoc test showed significant differences (***p < 0.0001, **p < 0.001, *p < 0.01) between the analyzed groups. NP: not processable.

Fig. 6. In vitro hydrolytic degradation kinetics of the hydrogels in NaOH (0.1 mM) at 37 #C.

Fig. 4. Swelling kinetics of GG and MeGG hydrogels in solutions with different ionic content: (A) water (no ions), (B) PBS (monovalent ions) and (C) DMEM with 10% FBS (mono and divalent ions). GG was not stable in water and dissolved in 30 min. Hence, swelling studies could not be carried out. (D) Confirmation of the ionic nature of the hydrogel shrinking behavior when immersed in PBS. High-MeGG hydrogels were used as an example. Samples were immersed in water for 30 min, then placed in a PBS solution for 20 h and again immersed in water for 30 min. The weight and size of the samples varied with the presence or absence of ions in the solution.

Fig. 1. (A) Schematic illustration of the synthesis of MeGG. 1H NMR spectra (T ¼ 50 #C) of (B) GG, (C) Low-MeGG and (D) High-MeGG recorded in D2O. Methyl group of the MA (ii) was located at d 2.09 ppm and vinyl groups of the MA (iii) were identified around d 5.5e7 ppm.

Fig. 7. Representative fluorescence micrographs of live (green) and dead (red) encapsulated NIH-3T3 cells in GG, Low-MeGG and High-MeGG immediately after encapsulation (day 0) and cultured in vitro for 3 days. The scale bars indicate 100 mm.

Fig. 2. FTIR-ATR spectra of GG, Low-MeGG and High-MeGG. The shoulder appearing around 1640 cm$1 corresponds to the C]C bond of the MA and is present on both Low-MeGG and High-MeGG. The absorption band present around 1770e1680 cm$1 corresponds to the C]O bond of the ester introduced in the chain.

Frequently asked questions

Q1. What are the contributions mentioned in the paper "Modified gellan gum hydrogels with tunable physical and mechanical properties" ?

Hence, this work presents a new class of GG hydrogels crosslinkable by both physical and chemical mechanisms.