Composite Hydrogels of Alkyl Functionalized Gellan Gum Derivative and Hydroxyapatite/Tricalcium Phosphate Nanoparticles as Injectable Scaffolds for bone Regeneration

An alkyl functionalized gellan gum derivative is here used to producehydrogels containing hydroxyapatite and tricalcium phosphate nanoparticlesas injectable nanostructured scaffolds for bone regeneration. The amphiphilicnature of the polysaccharide derivative along with its thermotropic behaviorand ionotropic crosslinking features make possible to produce injectable bonemimetic scaffolds that can be used to release viable cells and osteoinductivebiomolecules. The influence of different nanoparticles concentration on therheological and physicochemical properties of the injectable systems isstudied. It is found that the presence of inorganic nanoparticles reinforces the3D hydrated polymeric networks without influencing their injectability butimproving the physicochemical properties of ionotropic crosslinked hydrogelsproduced with two different curing media. Preliminary cytocompatibility testsperformed with murine preosteoblast cells revealed that gellan gum basedhydrogels can safely encapsulate viable cells. Loading and releaseexperiments for dexamethasone and stromal cell-derived factor-1demonstrate the drug delivery features of the obtained injectable systems.