Electrospun nano-polycaprolactone (PCL) is an ideal candidate for biomedical applications, as it mimics the extracellular matrix and possesses good biocompatibility, biodegradability and mechanical properties. Formic acid/acetic acid (FA/AA) and formic acid/acetone (FA/A) solvent systems were reported to be the safest solvents for the preparation of nanoscale electrospun polycaprolactone and they are also a common solvent with many natural polymers. In the present study a comparison between the electrospun fibers produced by the two systems was done. The optimum conditions for preparing PCL nanofibers were studied. The results indicated that finer fibers were found for formic acid/acetic acid in comparison with those produced by formic acid/acetone solvent system. In addition, it was found that optimum conditions for PCL nanofibers electrospinning were detected for 70:30 FA/AA solvent ratio with 15% PCL concentration and a tip to collector distance of 12.5 cm at 20 kV.

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This study aims at fabricating promising cytocompatible hybrid biocomposite scaffolds from chitosan (CS), hydroxyapatite (HAP) and lignin (L) for bonetissue engineering by using freeze-drying technique. Different ratios of HAP to L (50: 0, 37.5: 12.5, 25: 25 and 12.5: 37.5) were taken to determine the optimum ratio to obtain composite with superior properties. The mechanical and biological properties of the resulting composites were investigated. The mechanical results showed that the prepared composite with a ratio of 25 : 25 of HAP / L exhibited a remarkable enhancement in the mechanical properties compared to the others. Additionally, it was found from the in vitro results that the addition of L enhanced the water uptake value of the resulting scaffolds indicating increased hydrophilicity. As a result, a significant increase in the attachment and proliferation of MG-63 cell line (osteoblast like cells) was observed in composite scaffolds with L over the scaffold without L (CS/HAP). From these results, it could be suggested that the prepared composite scaffold with 25 : 25 of HAP/ L is very promising biomaterials in bone tissue-engineering as it exhibited a better mechanical and biological properties than the other prepared composites.

In this study, we have investigated the effect of adding zinc chloride (ZnCl2) on polycaprolactone (PCL) before and after electrospinning. The rheological properties and conductivity of ZnCl2/PCL solutions were measured prior to the electrospinning process. The resultant electrospun mats were characterized by SEM, contact angle, FTIR, XRD, mechanical properties, as well as its antibacterial and stem cell proliferation assessment were tested. It was found that the fibers became finer by increasing the zinc salt content. Moreover, stability increased slightly up to 5% Zn-PCL and also the hydrophilicity has been enhanced by 52%. By adding ZnCl2, the degradation rate and mechanical properties were significantly increased. Also, the resultant mats have shown antibacterial properties against S. aureus than E. coli. From the stem cells proliferation study, it can be observed that by increasing ZnCl2, the stem cells proliferation was significantly increased. Grooved multichannel nerve conduits were successfully fabricated by rolling the electrospun mats produced on corn husks which has shown better cell alignment and attachment. Hence, adding zinc chloride is a facile biocompatible enhancement to polycaprolactone nanofibers to be used in nerve regeneration.

Upon the tremendous spread of coronavirus, there is a need to develop biodegradable, multifunctional, antiviral masks that can be safely used without polluting the environment as conventional surgical masks do. In this study, a three-layered mask filter is designed and fabricated. The first two layers contain electrospun polyamide with dispersed nanoparticles (NPs) of TiO 2 and ZnO prepared via breakdown anodization. The third layer is composed of Nigella sativa oil (black seed oil) electrospun with polyamide and blended with chitosan to form an effective antiviral three-layered mask filter. The morphological characterization revealed the nanoscale features of the fabricated nanofibers with the ZnO and TiO 2 NPs being embedded in the polymeric matrix. The specimens showed good wettability, which is necessary for virus attachment and its subsequent decay. The assembled mask has shown very good mechanical properties. The cytotoxicity results revealed that the proposed mask filter has less cytotoxic effect on the A549 cell line than the commercial KN95 mask filter with maintaining a cell viability of 65.3%. The antiviral activity test showed a variable virucidal effect against human adenovirus on A549 cells. The proposed mask showed the highest effect on the virus followed by PA-ZnO and PA-TiO 2 films, which supports the assumption that the used NPs may have broad and promising effects on viruses when combined with the electrospun films.