Genipin versus Ferric Chloride cross-linked unmodified Gum Arabic/Chitosan/nano-Hydroxyapatite nanocomposite hydrogels as potential scaffolds for bone regeneration

Ferric chloride (FeCl(3)) and Genipin were utilized as cross-linkers to create two types of nanocomposite hydrogels through physical and covalent cross-linking methods, respectively. The hydrogels were composed of unmodified Gum Arabic (GA), Chitosan (Ch), and natural nano-Hydroxyapatite (nHA) using an acrylic acid solvent. Both the natural nHA and the FeCl(3) vs. genipin cross-linked GA/Ch/nHA nano-composite hydrogels were prepared and characterized using various in vitro and in vivo analysis techniques. The use of FeCl(3) and genipin cross-linkers resulted in the formation of novel hydrogels with compressive strengths of (15.43–22.20 MPa), which are comparable to those of natural cortical bone. In vivo evaluation was conducted by creating calvarial defects (6 mm) in Sprague–Dawley male rats. The results showed the formation of new, full-thickness bone at the implantation sites in all groups, as evidenced by digital planar tomography and histological staining with Hematoxylin and Eosin stain (H & E). Additionally, the use of genipin as a cross-linker positively affected the hydrogel's hydrophilicity and porosity. These findings justify further investigation into the potential of these nanocomposite hydrogels for bone regeneration applications.