Stimuli-responsive piezoelectricity in electrospun polycaprolactone (PCL)/Polyvinylidene fluoride (PVDF) fibrous scaffolds for bone regeneration

Polymeric scaffolds are a determinant part of modern tissue engineering owing to their great diversity, adaptability, and processability. Interestingly, the physical properties of these scaffolds, e.g., porosity, mechanical properties, and biocompatibility, can be tuned to make them smart and stimuli-responsive. In this regard, piezoelectric materials can be applied to stimulate bone regeneration by converting mechanical impulses to electrical signals. In the present research, fibers made of various blend ratios of polyvinylidene fluoride (PVDF)/polycaprolactone (PCL) were fabricated, investigated and optimized to promote bone regeneration. Uniform fibers containing β-phase PVDF were obtained due to the simultaneous stretching and high voltage applied during electrospinning. Furthermore, components interaction, crystallinity, and piezoelectric behavior were estimated through fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and piezometery, respectively. The samples showed improved wettability and controlled biodegradability, and the piezoelectric charge output reached up to 7.5 pC/N in the sample containing 70 wt% PVDF. At the same time, these scaffolds could provide mechanical properties close to the native bone tissue relying on the PVDF component. In vitro assessments demonstrated that the composite scaffolds were biocompatible and could support cell attachment and proliferation. Moreover, their piezoelectric behavior promoted stem cell differentiation into osteoblasts. Considering the obtained results, the potential of piezoelectric PVDF/PCL blend fibers for bone scaffolds is indisputable.