Optimizing gelling parameters of gellan gum for fibrocartilage tissue engineering

Abstract

Gellan gum is an attractive biomaterial for fibrocartilage tissue engineering applications because it is cell compatible, can be injected into a defect, and gels at body temperature. However, the gelling parameters of gellan gum have not yet been fully optimized. The aim of this study was to investigate the mechanics, degradation, gelling temperature, and viscosity of low acyl and low/high acyl gellan gum blends. Dynamic mechanical analysis showed that increased concentrations of low acyl gellan gum resulted in increased stiffness and the addition of high acyl gellan gum resulted in greatly decreased stiffness. Degradation studies showed that low acyl gellan gum was more stable than low/high acyl gellan gum blends. Gelling temperature studies showed that increased concentrations of low acyl gellan gum and CaCl₂ increased gelling temperature and low acyl gellan gum concentrations below 2% (w/v) would be most suitable for cell encapsulation. Gellan gum blends were generally found to have a higher gelling temperature than low acyl gellan gum. Viscosity studies showed that increased concentrations of low acyl gellan gum increased viscosity. Our results suggest that 2% (w/v) low acyl gellan gum would have the most appropriate mechanics, degradation, and gelling temperature for use in fibrocartilage tissue engineering applications.

Development of gellan gum containing formulations for transdermal drug delivery: Component evaluation and controlled drug release using temperature responsive nanogels

“…At the lower gellan gum concentration the density of the solid hydrogel film decreases, reducing the diffusion pathways and thus increasing drug release (Baumgartner et al, 2002). While gellan gum degradation kinetics may affect drug release from the formulations developed, studies have reported that gellan gum hydrogels have a low degradation rate and are stable for up to 3 weeks (Lee et al, 2011). Results demonstrating that isopropyl alcohol is an important element to increase diclofenac transport in the semisolid gel formulation, especially during the first 4 hours, are consistent with other studies showing that isopropyl alcohol increases drug permeation in semisolid formulations, mostly due to its interaction with the lipid components in the skin (Güngör et al, 2004;Takahashi et al, 1991).…”

Cell-laden hydrogels for osteochondral and cartilage tissue engineering

“…The results of 150-day in vitro culture demonstrated that the modified injectable chondrocyte-laden gellan gum hydrogel with low gelation temperature well maintained the chondrocyte phenotype with high viability and promoted cartilage ECM formation in a long-term scale. In addition to oxidation, gelation temperature can also be tuned by changing proportion of low/high acyl gellan gum and the concentration of covalent cations to optimize cell encapsulation and injectability [153]. …”

Natural polymers for the microencapsulation of cells

“…The degradation rate of the gel is influenced by the number of acyl groups; in particular, hydrogels made of low acyl gellan gums degrade more slowly than the high acyl forms [148]. Furthermore, gellan gum is degraded by the enzyme galactomannanase [149].…”