Synthesis and Evaluation of SrO-Doped Hydroxyapatite Nanoparticle Hydrogels for Bone Regeneration

Hydrogels are multifunctional biomaterials widely utilised in biomedical applications owing to their biocompatibility, water retention capabilities and adjustable properties. Nonetheless, their restricted mechanical strength and bioactivity limit their application in bone tissue engineering. Present study focused on the development and evaluation of SrO-doped hydroxyapatite nanoparticles (SrO–HA) integrated into a polyvinyl alcohol/carboxyl methyl chitosan (PVA/CMC) hydrogel matrix to improve mechanical and osteogenic properties. The SrO@HA/PVA/CMC composite hydrogels were synthesised through a freeze-thaw physical crosslinking method and characterised to assess the porosity, swelling behaviour, ion release and biomineralisation, utilizing SEM, EDS and FTIR techniques. The biocompatibility and osteogenic potential were evaluated using rBMSCs via CCK-8 assays, alkaline phosphatase activity measurement and alizarin red staining. The hydrogels exhibited an interconnected porous structure, characterised by improved mechanical stability and sustained release of strontium ions. Elevated concentrations of SrO–HA (2%, 4% and 10%) enhanced biomineralisation and osteogenic differentiation, with the 4% and 10% hydrogels exhibiting superior efficacy. Sustained ion release facilitated rBMSC proliferation, increased ALP activity and resulted in significant extracellular matrix mineralisation. The biomimetic characteristics of SrO–HA, along with the three-dimensional porous structure of the hydrogels, facilitated these effects. The hydrogels facilitated apatite formation upon incubation in simulated body fluid, confirming their biomineralisation potential. The results indicate the possibility of SrO@HA/PVA/CMC composite hydrogels in bone tissue engineering.