Polyvinylidene fluoride (PVDF) is one of the most important piezoelectric polymers. Piezoelectricity in PVDF appears in polar b and ɣ phases. Piezoelectric fibers obtained by means of electrospinning may be used in tissue engineering (TE) as a smart analogue of the natural extracellular matrix (ECM). We present results showing the effect of rotational speed of the collecting drum on morphology, phase content and in vitro biological properties of PVDF nonwovens. Morphology and phase composition were analyzed using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. It was shown that increasing rotational speed of the collector leads to an increase in fiber orientation, reduction in fiber diameter and considerable increase of polar phase content, both b and g. In vitro cell culture experiments, carried out with the use of ultrasounds in order to generate electrical potential via piezoelectricity, indicate a positive effect of polar phases on fibroblasts. Our preliminary results demonstrate that piezoelectric PVDF scaffolds are promising materials for tissue engineering applications, particularly for neural tissue regeneration, where the electric potential is crucial.
This article presents little known facts sampled from the notes and personal records of Professor Stanis$aw Pigoń and Karol Wojtyła. The two met for the first time in 1938, when young Wojtyła began his studies at the Polish Department of the Jagiellonian University. A bond of mutual liking and respect, based on similar personalities and similar war experiences, morphed into an abiding friendship in the years after the war. The article chronicles that friendship on the basis of documents and private papers held in the Jagiellonian Library (Professor Pigoń’s Archives) and the Archives of the Metropolitan Curia in Cracow. Wojtyła, when he became Pope John Paul II always spoke warmly about his university teachers, especially about Professor Pigoń.