In the last decade, the use of polymer nanofibers fabricated by electrospinning has attracted much attention, especially in the field of biomedicine and pharmaceuticals. There is already much research on the potential use of nanofibers, but there is lack of knowledge on the interactions of nanofibers with living systems. Particularly important with regard to the application of nanofibers is their safety, which has not yet been adequately researched.
In my master's thesis, we looked at the influence of the chemical properties of electrospun nanofibers on their safety, specifically their citotoxicity. Synthetic (polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polycaprolactone (PCL), polyethylene oxide (PEO)) and natural polymers (hydroxypropylcellulose (HPC), gelatin, chitosan) were used. The diameter of the fabricated nanofibers and the pore size were evaluated using a scanning electron microscope, the polarity of the surface of the nanofibers was investigated by measuring the contact angle,
and the crystallinity of the polymers was determined by differential scanning calorimetry. We investigated the relationships between the process parameters and the properties of the nanofibers to facilitate their fabrication. We also found that the contact angle of nanofibers made of hydrophilic polymers decreased compared to films. Whereas the contact angle of nanofibers
made of hydrophobic polymers increases due to the uneven surface of the nanofibers. A test of metabolic activity closely related to lymphocyte viability was used to evaluate the effect of nanofibers on cytotoxicity to these cells. Nanofibers made of HPC, PVP, PVA, and PCL polymers and composite nanofibers made of PCL/gelatin did not exhibit cytotoxicity to lymphocytes compared to samples without nanofibers. Reduced metabolic activity of lymphocytes was observed for PEO nanofibers and composite nanofibers of PEO/chitosan, but it was not statistically significant. Nanofibers made of PVP and PVA were also thermally stabilized. For PVP, no significant difference in lymphocyte activity was observed after treatment, whereas for PVA, partial chemical degradation occurred during stabilization,
producing acetic acid, which is likely the cause of decreased lymphocyte viability. Decreased metabolic activity of lymphocytes was observed in PCL-irradiated nanofibers compared to non irradiated PCL. In summary, the safety of polymers is not affected by electrospinning, but can be altered by temperature or UV radiation.
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