Despite a lot of intensive research in the field of polymer nanofibers as wound-healing and tissue-regeneration materials, the behavior of cells in contact with nanofibers in vitro as well as in vivo is still not well understood. However, this knowledge is crucial for the design of nanofibrillar materials that are suitable for biomedical applications. Therefore, in this study we present the preparation of poly(vinyl alcohol) (PVA) nanofibers from a physico-chemically characterized polymer solution by electrospinning together with a stabilization method to preserve the morphology of the nanofibers in aqueous conditions. An investigation of the effects of a nanofibrillar scaffold on the growth of human keratinocytes showed that randomly oriented PVA nanofibers delay the keratinocytesʼ adhesion but improve their strength, greatly alter their morphology, increase their metabolic activity and limit their mobility. We have shown that due to the small interfiber pores, the whole cells are unable to penetrate into nanofibrillar network efficiently. However, flexible cell parts can penetrate into the nanofibrillar network, whereas the cell nuclei stay on the surface of electrospun scaffold. Additional reason for poor cell mobility is random orientation of nanofibers, which does not provide continuous routes for successful cell infiltration. Therefore, nanofibrillar support with nanosized interfiber pores could potentially be used to enable an efficient cell proliferation and accelerate surface-wound healing, but not for 3D tissue regeneration. Finally, we showed that aligned nanofibers can successfully direct the migration and proliferation of cells, which is a crucial property of nanomaterials for the successful regeneration of tissues with a highly organized structure.
COBISS.SI-ID: 3339121
Electrospinning is an efficient and flexible method for nanofiber production, but it is influenced by many systemic, process, and environmental parameters that govern the electrospun product morphology. This study systematically investigates the influence of relative humidity (RH) on the electrospinning process. The results showed that the morphology of the electrospun product (shape and diameter) can be manipulated with precise regulation of RH during electrospinning. Because the diameter of nanofibers correlates with their rigidity, it was shown that RH control can lead to manipulation of material mechanical properties. Finally, based on the solution's rheological parameter - namely, phase shift angle - we were able to predict the loss of homogenous nanofiber structure in correlation with RH conditions during electrospinning. This research addresses the mechanism of RH impact on the electrospinning process and offers the background to exploit it in order to better control nanomaterial properties and alter its applicability.
COBISS.SI-ID: 3496561
Nanofibers prepared from poly (vinyl alcohol) (PVA) using the electrospinning process have received a great deal of attention over the past decade due to their outstanding characteristics and their applicability in the field of biomedicine, coupled with their innovative preparation. However, the success of the electrospinning process depends strongly on the parameters of the source polymer solution. Of these parameters the majority of published papers routinely examine the viscosity, conductivity and surface tension, while other, indeed crucial, physical characteristics are only rarely investigated. In the present work, the emphasis was also on a comprehensive investigation of the bulk and interfacial rheology as well as on the small-angle X-ray scattering (SAXS) of PVA solutions. A detailed analysis revealed rearrangements of the molecules in the solutions depending on the polymer concentration proved by measured surface tension, determined apparent specific volume and radius of gyration. Further, we found out that smooth nanofibers are formed only from those PVA solutions, where properly firm internal polymer structures that can be oriented in the direction of an applied electric field, enable complete polymer elongation during the electrospinning. It is important to note that this is the first time that suchan extensive study has been made and, our findings provide a better insight into the physical properties of the solutions for electrospinning as well as their decisive influence on the formation of the nanofibers.
COBISS.SI-ID: 3362417