Advanced Guar Gum/Polyvinyl Alcohol/MnP-Based Smart Hydrogel for Promoting Osteoblastic Proliferation

Exposed bone fractures (EBF) represent a critical clinical challenge due to the simultaneous disruption of bone and surrounding soft tissues, requiring multifunctional biomaterials capable of providing mechanical adaptability, structural stability, and biological support. In this study, we developed a smart, shear-thinning, self-healing hydrogel composed of guar gum, polyvinyl alcohol, gelatin, collagen, and chitosan-stabilized manganese phosphate (MnP) micro/nanoparticles. MnP particles were synthesized via a quitosan/ascorbic acid-assisted route and characterized by SEM, DLS, FTIR, and EDS, confirming spherical morphology and successful phosphate incorporation. The resulting nanostructured hydrogel exhibited high porosity (>85%), controlled swelling, pH responsiveness, and efficient rheological self-recovery (>90% storage modulus restoration under cyclic deformation). The system demonstrated non-Newtonian behavior and effective adhesion to skin without irritation after 10 h of contact. In vitro assays using MC3T3-E1 pre-osteoblasts confirmed cytocompatibility and concentration-dependent modulation of cell migration. The incorporation of MnP micro/nanoparticles contributes potential osteogenic functionality while preserving mechanical integrity and dynamic responsiveness. These findings suggest that the developed nanocomposite hydrogel represents a promising auxiliary platform for the treatment of exposed bone fractures.