Biocompatible nanofibrous scaffolds incorporating titanium dioxide and melatonin to enhance osteogenesis in ADMSCs

Large bone defects remain a significant clinical challenge due to the limitations of autografts and allografts, prompting interest in bioactive scaffolds for bone tissue engineering. This study aimed to develop and evaluate electrospun nanofibrous scaffolds composed of polycaprolactone (PCL) and polylactic acid (PLA), incorporating titanium dioxide nanoparticles (TiO₂) and melatonin (Mel), to enhance their osteogenic differentiation potential. PCL/PLA, PCL/PLA/TiO₂, PCL/PLA/Mel, and PCL/PLA/TiO₂/Mel scaffolds were fabricated via electrospinning and characterized for morphology, fiber diameter, and mechanical properties. Biological performance was evaluated using adipose-derived mesenchymal stem cells (ADMSCs) through MTT assay, calcium content, alkaline phosphatase (ALP) activity, and osteogenic gene expression. TEM confirmed uniform TiO₂ nanoparticle distribution without agglomeration. All scaffolds exhibited continuous cylindrical fibers without defects. TiO₂ incorporation reduced tensile strength but increased elongation, while melatonin enhanced tensile strength. MTT assays confirmed biocompatibility and higher proliferation in TiO₂- and Mel-containing scaffolds. Calcium content and ALP activity were significantly higher in TiO₂- and/or Mel-modified scaffolds, with the PCL/PLA/TiO₂/Mel group showing the most significant osteogenic differentiation potential. Gene expression analysis revealed upregulated osteopontin, osteonectin, and osteocalcin in TiO₂- and Mel-containing scaffolds. Co-incorporation of TiO₂ nanoparticles and melatonin into electrospun PCL/PLA scaffolds synergistically enhances osteogenic differentiation and may serve as a promising strategy for bone tissue regeneration.