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 Nb2O5 on physicochemical and biological properties was investigated. Electrospinning conditions were optimized, yielding nearly bead-free, randomly oriented fibers. SEM analysis revealed that Nb2O5 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 Nb2O5 and PHB, mainly involving the amorphous phase. Furthermore, the incorporation of an increasing amount of Nb2O5 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-Nb2O5 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.