Piezoelectric PCL/PVDF core-shell nanofibrous scaffolds for enhanced osteogenesis under dynamic loading

Biomimetic tissue engineering scaffolds must recapitulate the specific structural, biochemical, and electromechanical properties of the native extracellular matrix (ECM) to support cellular function and tissue regeneration. Bone exhibits piezoelectricity, converting mechanical stress into electrical signals that regulate mechanotransduction and guide its remodeling. Likewise, piezoelectric scaffolds can replicate this native ECM feature, providing mechanical support and bioactive stimuli that promote cell growth and differentiation. To develop a suitable bone scaffold with desirable mechanical, biological, and piezoelectric properties, a core-shell nanofibrous scaffold consisting of PCL-PVDF (Polycaprolactone-Polyvinylidene fluoride) and PCL-PVDF-HA (Hydroxyapatite-incorporated) fibers (PVDF or PVDF-HA as shell) was fabricated through coaxial electrospinning. Scanning electron microscopy (SEM) was used to investigate the microstructural characteristics, and images of fractured fiber cross-sections confirmed the successful formation of the core-shell morphology. Piezoelectric properties were initially characterized by XRD and ATR-FTIR, and further validated by measuring the output voltage with an oscilloscope. The core-shell PCL-PVDF scaffold exhibited the highest piezoelectric response compared to the neat PCL, neat PVDF, and PCL-PVDF-HA fibers. The effect of mechanically induced electrical signals on cell behavior was investigated. ALP activity and alizarin red staining tests on human adipose-derived stem cells cultured on scaffolds under dynamic tensile loading at specific strain and frequency confirmed their osteogenic differentiation. Overall, the results confirmed the promising potential of PCL-PVDF nanofibrous scaffold for bone tissue engineering applications.