Development and characterization of 3D bioprintable and mechanically reinforced hydrogel based on gellan gum/methylcellulose/cellulose nanocrystals

3D bioprinting has appeared as a promising technology in the area of tissue engineering. Here, bioinks composed of various concentrations of gellan gum (GG), methylcellulose (MC) and cellulose nanocrystal (CNC) were developed for extrusion-based bioprinting. Among the binary mixtures of GG/MC, the blend of 1% w/w GG and 4% w/w MC (1GG/4MC) provides the best property to further tailoring as bioink. For the ternary mixtures of GG/MC/CNC, 1GG/4MC/4% w/w CNC (1GG/4MC/4CNC) provide the best printability characteristic but not sufficient mechanical performance. Ionic crosslinking using various concentrations of salts including CaCl2, KCl and NaCl were applied to improve the mechanical strength. Both 1GG/4MC/4CNC/0.022% w/w CaCl2 (1GG/4MC/4CNC/0.022CaCl(2)) and 1GG/4MC/4CNC/0.075% w/w KCl (1GG/4MC/4CNC/0.075KCl) exhibit mechanical stability with good printability. Both provide higher compressive modulus than 1GG/4MC/4CNC and 1GG/4MC, and show great shear-thinning and thixotropic behaviors. They show porous microstructure and sufficient swelling ratio to maintain high cell viability. Excellent biocompatibility of 1GG/4MC/4CNC/0.022CaCl(2) and 1GG/4MC/4CNC/0.075KCl is demo nstrated with cell viability of 119.55% and 100.77%, respectively, based on MTT assay. A good cell viability of 97%-98% up to 14 days was attained for both bioprinted constructs. Taken together, these novel 1GG/4MC/4CNC/0.022CaCl2 and 1GG/4MC/4CNC/0.075KCl hydrogels exhibit good attributes for a promising 3D bioprinting material.