1Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran.
2Department of Life Sciences Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
3Chemical Engineering Group, Faculty of Petroleum and Petrochemical Engineering, Hakim Sabzevari University, Sabzevar, Iran
4Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran
Today, electrospinning is using to produce wound dressings with ideal properties like biodegradability, excess oxygen absorption, proper elasticity, non-toxic and non-antigenic properties. One of the problems with wound dressing is bacterial infections. Due to the high antibiotic resistance among bacterial pathogens, a replacement alternative is needed. Over the past decades, the antibacterial activity of metal nanoparticles, such as silver nanoparticles, has been considered. Silver nanoparticles kill bacteria by damaging the DNA, cell membranes and inhibiting the respiratory enzyme activity. Several methods are applied to produce silver nanoparticles, but chemical methods of synthesizing them are often expensive and toxic. For this reason, the method of green synthesis by fungi can be suitable. The Schizophyllum commune is a fungus of the basidiomycetes, which is broadly used in several industries. Schizophyllan (SPG) from S. commune with anti-inflammatory, immune-stimulating, and collagen-producing properties may be good candidates for use in wound dressings. In this study, silver nanoparticles were synthesized by in-situ and ex-situ (by S. commune) methods. Then nanofibers containing SPG and PVA were prepared with these nanoparticles. The FESEM images of schizophyllan nanofibers (PVA/SPG), schizophyllan nanofibers with in-situ silver nanoparticle (PVA/SPG-inAgNPs), and schizophyllan nanofibers with ex-situ silver nanoparticle (PVA/SPG/exAgNPs) showed that the presence of silver nanoparticles in the solution reduced the diameter of the nanofibers by changing the conductivity of the solution. The diameters of PVA/SPG-inAgNPs and PVA/SPG/exAgNPs nanofibers were 169 and 126 nm, respectively. These differences may be due to nanoparticles' presence in SPG structure in PVA/SPG/exAgNPs nanofibers. Examination of nanofibers' antibacterial activity showed that all nanofibers inhibit E. coli and S. aureus' growth. PVA/SPG-inAgNPs significantly (p<0.05) inhibit E. coli and S. aureus' growth by 86% and 61%, respectively. PVA/SPG/exAgNPs had a notable inhibitory effect (p<0.05) on bacterial growth, which shows good anti-microbial properties of the produced silver nanoparticles by the ex-situ method. It inhibits the growth of E. coli and S. aureus by 95% and 90%, respectively. This inhibitory effect is associated with the release of silver ions in bacterial culture media. Silver nanoparticles bind to cell membrane proteins and cause changes in the membrane. Silver ions also inhibit the function of enzymes and cause cell membrane leakage and eventually bacterial death. Cytotoxicity analysis on the L929 cell line shows that the inhibitory effect on the cells' growth and survival was not observed. One of the features of suitable wound coating is non-toxicity and compatibility with human tissue. The synthesis of nanoparticles from green synthesis by fungi seems to have a high potential for synthesizing silver nanoparticles. The production of silver nanoparticles by this method is inexpensive and non-toxic. The nanofibers produced with these nanoparticles (PVA/SPG/exAgNPs) and having a suitable morphology and diameter also have more antibacterial activity. This study indicates that nanofibers have no toxic effect, and are biocompatible and have no inhibitory effect on cell growth and proliferation.