Cerium oxide nanoparticle-integrated nanocellulose/sodium alginate hydrogel scaffolds: a promising platform for bone tissue engineering

The critical-sized bone defects arising due to trauma and other congenital disorders require external intervention for healing. The limitations associated with conventional autografts and allografts can be overcome through Bone Tissue Engineering (BTE) by inducing the regeneration of damaged tissue. In the current study, cerium oxide nanoparticles (CeNPs) green synthesized from Justicia adhatoda aqueous leaf extract were incorporated into Cellulose nanofiber/Sodium alginate (CNF/SA) polymer matrix to form sustainable biomaterial scaffold. The particle size of the CeNPs was determined in the range 4-8 nm using high-resolution transmission electron microscopy (HR-TEM). Fourier transform-infrared (FT-IR) spectroscopy revealed the characteristic functional groups of the constituents. The porous morphology of the hydrogels is evidenced in field-emission scanning electron microscopy (FESEM) and the scaffolds exhibited dose- dependent swelling ratios ranging from 180 to 60%. The MTT assay results revealed the excellent cytocompatibility greater than 90% for all the hydrogel formulations. The composites exhibited remarkable antibacterial potential against S. aureus and E. coli bacterial strains. The assessment of osteogenic potential of hydrogels using alizarin red staining (ARS) and alkaline phosphatase (ALP) assay demonstrated remarkable osteogenic responses with maximum ALP activity observed at 100 µg/mL and enhanced calcium deposition for the hydrogel formulation containing highest concentration of CeNPs. The synergistic effect of each constituent may have resulted in the elevated levels of calcium deposition and enhanced ALP activity with increase in concentration of CeNPs. The results highlight the potential of the CNF/SA/CeNP hydrogel composites as promising platform for bone tissue regeneration applications.