Structural changes in PVDF fibers due to electrospinning and its effect on biological function

Polyvinylidine fluoride (PVDF) is being investigated as a potential scaffold for bone tissue engineering because of its proven biocompatibility and piezoelectric property, wherein it can generate electrical activity when mechanically deformed. In this study, PVDF scaffolds were prepared by electrospinning using different voltages (12-30 kV), evaluated for the presence of the piezoelectric β-crystal phase and its effect on biological function. Electrospun PVDF was compared with unprocessed/raw PVDF, films and melt-spun fibers for the presence of the piezoelectric β-phase using differential scanning calorimetry, Fourier transform infrared spectroscopy and x-ray diffraction. The osteogenic differentiation of human mesenchymal stem cells (MSCs) was evaluated on scaffolds electrospun at 12 and 25 kV (PVDF-12 kV and PVDF-25 kV, respectively) and compared to tissue culture polystyrene (TCP). Electrospinning PVDF resulted in the formation of the piezoelectric β-phase with the highest β-phase fraction of 72% for electrospun PVDF at 25 kV. MSCs cultured on both the scaffolds were well attached as indicated by a spread morphology. Cells on PVDF-25 kV scaffolds had the greatest alkaline phosphatase activity and early mineralization by day 10 as compared to TCP and PVDF-12 kV. The results demonstrate the potential for the use of PVDF scaffolds for bone tissue engineering applications.