Sustainable fabrication of Sr-doped hydroxyapatite-polymer nanofiber composites with enhanced physicochemical and functional properties

The healing of large segmental bone defects remains a major challenge in regenerative medicine, prompting the development of biomimetic scaffolds that exhibit osteoconductivity, biocompatibility, bioactivity, and biodegradability similar to native bone tissue. In this study, a flexible electrospun nanofiber scaffold composed of bovine bone-derived strontium-doped hydroxyapatite (Sr-HAp), polymethylmethacrylate (PMMA), and cellulose acetate (CA) was fabricated to replicate the natural extracellular matrix of human bone. Sr-HAp was synthesized through thermal degradation of bovine bone followed by incorporation of strontium nitrate, and the resulting nanoparticles were uniformly embedded in the PMMA/CA nanofiber network using electrospinning. Morphological and structural analyses confirmed that Sr-HAp was well dispersed within the fibers, maintaining a crystalline structure without aggregation. The addition of CA enhanced the hydrophilicity and water absorption capacity of the scaffold, leading to improved swelling and degradation behaviour. Moreover, the Sr-HAp/PMMA/CA nanofiber scaffold exhibited significant cytotoxic effects against human prostate cancer (PC-3) and epidermoid carcinoma (A431) cell lines, with inhibition rates of 34.43 % and 61.65 % at 200 μg/mL, respectively. Further, the cytocompatibility of the Sr-HAp/PMMA/CA nanofiber scaffold against the human embryonic kidney (HEK293) cell line shows a non-toxic nature with the cytocompatibility of 94.9 % at 200 μg/mL. Overall, the biogenic Sr-HAp/PMMA/CA electrospun nanofiber scaffold demonstrates excellent physicochemical and biological properties, highlighting its potential as a promising material for tissue regeneration applications.