Aligned electrospun porous P34HB/lecithin scaffold for bone tissue regeneration

Bone tissue engineering has emerged as a promising restorative strategy for bone regeneration, yet it remains challenging to develop an appropriate scaffold with optimal porous microstructure for bone repair. Unlike random fibrous scaffolds, the aligned nanofibrous structure could provide contact guidance for cell orientation and enhances mechanotransduction signaling. The purpose of this study was to investigate the effect of aligned electrospun poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) nanofibrous scaffold with lecithin on guided bone regeneration. In this study, aligned P34HB scaffold (PA group) and random P34HB scaffold (PR group) were fabricated via electrospinning with different speeds of rotating collector, respectively. And lecithin was coated on PA scaffolds (PA/L groups) by immersion method. The morphology, phase composition, and physical properties of these scaffolds were characterized. Meanwhile, cellular behaviors of bone marrow mesenchymal stem cells (BMSCs), including proliferation, adhesion, osteogenic differentiation, and related gene expression, were also investigated. Finally, a rat critical calvarial defect model was used to evaluate the biocompatibility and effect of these scaffolds on bone repair. The mean fiber diameters of PR and PA scaffolds were 893.0 ± 189.4 nm and 832.6 ± 193.1 nm, respectively. And Lecithin coating significantly reduced the water contact angle from 112.3° ± 3.5° (PA) to 48.6° ± 2.1° (PA/L) (P < 0.05). The in vitro results demonstrated that PA/L scaffolds showed the highest ALP activity at day 7 and mineralization at day 14. Gene expression analysis revealed that PA/L scaffolds significantly upregulated Alp and Col1a1 at early time points. Furthermore, the in vivo micro-CT analysis revealed that the PA/L group achieved the highest bone volume fraction of 38.7% ± 3.2% at 4 weeks post-implantation. All these results above indicated that aligned nanofibers of P34HB scaffolds in combination with the lecithin could exert a synergistic effect on promoting osteogenesis and regeneration of bone defects. This study represents the first successful combination of aligned P34HB electrospun fibers with soy lecithin coating. The PA/L scaffold could not only topographically guide cell growth but also significantly enhance hydrophilicity and osteogenic differentiation, which could offer a synergistic strategy for bone tissue regeneration. Thus, aligned P34HB scaffold with lecithin showed great application potential for bone tissue regeneration.