Piezoelectric core-shell fibrous scaffolds of PVDF-ZnO/PCL for bone regeneration

One promising approach to improve bone regeneration is the use of piezoelectric scaffolds, which can positively affect cell growth and proliferation. PVDF, as a piezoelectric polymer, is an attractive candidate for use as a bone scaffold. However, other components should be added to PVDF to improve wettability, biodegradability, biocompatibility, and other biological properties. In this research, PVDF containing ZnO-PCL core-shell fiber composites were fabricated by coaxial electrospinning. TEM images were used to determine the proper electrospinning parameters that can provide a homogenous core/shell structure. Afterward, the surface of the samples was corona-treated to improve wettability. FTIR spectroscopy was used to estimate the piezoelectric β phase fraction in the core PVDF fibers, which demonstrated that the highest β phase fraction was obtained in the presence of 0.5 wt% ZnO nanoparticles. The tensile test results revealed that by adding ZnO nanoparticles to the scaffolds, the ultimate tensile strength of samples decreased, yet the values were in the acceptable range. The water contact angle measurements showed that the corona treatment could successfully reduce the contact angle from about 130° to 60°. Based on the obtained results, the F-0.5Z sample was chosen as the optimum sample and was used for biological and piezoelectric assessments. It rendered the piezoelectric output of 6.5 pC/N. In vitro assessments showed that this sample is biodegradable and bioactive, could support cell attachment and proliferation and intensified calcium mineralization. The composite containing 0.5 wt% ZnO had the best result and could be used as a scaffold in bone regeneration and repair.