Electrospun membranes of polyhydroxybutyrate–niobium pentoxide as potential scaffolds for bone tissue engineering

In recent years, the fabrication of biomimetic electrospun membranes has represented a promising approach for bone tissue engineering. In this study, electrospun composite fibers based on polyhydroxybutyrate (PHB) and different amounts of niobium oxide were developed, and the influence of Nb 2 O 5 on physicochemical and biological properties was investigated. Electrospinning conditions were optimized, yielding nearly bead-free, randomly oriented fibers. SEM analysis revealed that Nb 2 O 5 affected fiber size, reducing their diameters by approximately 16 %, whereas it did not influence membrane wettability, suggesting that the particles were embedded within the polymer matrix. FTIR-ATR analysis revealed physical interactions between Nb 2 O 5 and PHB, mainly involving the amorphous phase. Furthermore, the incorporation of an increasing amount of Nb 2 O 5 decreased PHB crystallinity and significantly enhanced tensile strength and Young’s modulus, the latter reaching a value of 85.50 ± 0.15 MPa for PHB-Nb 2 O 5 94/6 w/w (PHB-Nb6), three times that of pure PHB. Hydrolitic degradation study suggested that the presence of oxide slightly reduced membrane degradation rate in the early stage. All oxide-containing membranes showed no toxicity to hBMSCs and exhibited osteoinductive potential, with concentration-dependent increases in mineralization and ALP activity, peaking with PHB-Nb6. Finally, qRT-PCR analysis showed upregulated expression of osteogenic differentiation-related genes in hBMSCs cultured with PHB-Nb membranes. • PHB-based fibers with different amounts of Nb 2 O 5 were prepared by electrospinning. • The effect of Nb 2 O 5 on membrane properties was investigated. • FTIR revealed physical interactions between Nb₂O₅ and the PHB amorphous phase. • A higher Nb content reduced PHB crystallinity and enhanced its mechanical properties. • Nb enhanced mineralization, ALP activity, and osteogenic gene expression of hBMSCs.