Summary
Bone-tissue scaffolds work best when they combine a biodegradable fibrous framework with a bone-like mineral that encourages cells to become bone-forming. This study designs bio-based biocomposite scaffolds from poly(3-hydroxybutyrate) (PHB) and evaluates how they drive the osteogenic differentiation of human mesenchymal stromal cells (hMSCs). Four scaffold types were produced: electrospun neat PHB, electrospun PHB/gelatin, electrospun PHB/gelatin blended with hydroxyapatite nanoparticles (nHA), and PHB/gelatin fibres onto which nHA was simultaneously electrosprayed. Electron microscopy showed that blending traps most nHA inside the fibres, whereas the combined electrospinning/electrospraying route coats the fibre surface with the bioceramic. Gelatin-containing scaffolds supported faster cell growth, and over 21 days the nHA-sprayed scaffold gave the highest alkaline phosphatase activity and matrix mineralisation — showing that exposing nHA at the fibre surface most effectively promotes bone-forming differentiation.