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Oxidant environment and inflammation are the leading cause of chronic wounds such as diabetic ulcers. A dressing containing antioxidants would ensure accelerated wound healing. In this study, electrospun gold nanoparticle (GNP)-embedded nanofibers were developed. GNPs (about 7 nm) were synthesized using saffron extract as a reducing and capping agent (GNP-EXT). For comparison, nanoparticles of the same size were also synthesized using citrate (GNP-CIT). Nanoparticle colloids showed a zeta potential of -27 mV. FTIR confirmed the presence of the extract molecules on the nanoparticles. DPPH assay demonstrated the significant radical scavenging properties of the GNP-EXT. The effect of nanoparticles on the viability of NIH3T3 mouse fibroblast cells was evaluated with an MTT assay that showed no significant toxicity of nanoparticles even in the highest concentration of 250 ppm. Then poly (ɛ-caprolactone) (PCL)- Collagen nanofibers containing GNPs were electrospun. By using SEM, TEM, ATR-FTIR, and contact angle measurement, the nanofibers were characterized. Proper cell adhesion and spreading was observed on nanofibers by SEM and Alamar blue assay illustrated appropriate cyto-compatibility on the obtained nanofibers after 5 days of cell seeding. Wound healing assay also confirmed the cell supporting properties and biocompatibility. The results suggest that saffron-synthesized GNP-loaded nanofibers would be considered as potential wound dressings.

The pandemic outbreak of SARS-CoV-2, with millions of infected patients worldwide, has severely challenged all aspects of public health. In this regard, early and rapid detection of infected cases and providing effective therapeutics against the virus are in urgent demand. Along with conventional clinical protocols, nanomaterial-based diagnostics and therapeutics hold a great potential against coronavirus disease 2019 (COVID-19). Indeed, nanoparticles with their outstanding characteristics would render additional advantages to the current approaches for rapid and accurate diagnosis and also developing prophylactic vaccines or antiviral therapeutics. In this review, besides presenting an overview of the coronaviruses and SARS-CoV-2, we discuss the introduced nanomaterial-based detection assays and devices and also antiviral formulations and vaccines for coronaviruses.

Multi-layer electrospun structures have attracted interests as multifunctional wound dressings. In the present study, a double-layered nanofibrous construct was prepared out of pure type I collagen nanofibers (as the inner layer) and collagen/PLLA/Zataria Multifloraessential oil (as the outer layer). Extracted essential oil was analyzed by GC–Mass Spectrometry. Bi-layers were characterized by SEM, ATR-FTIR and XRD. Water contact angle and swelling studies demonstrated hydrophilicity and a high water absorption capability (1504% of the initial weight) of the nanofibers, respectively. Also, the essential oil showed a strong antioxidant activity (IC50: 7.4 ppm). Cumulative release profile of the essential oil from nanofibers illustrated a burst release in about 120 min and then, a sustained release up to 72 h. Broth micro-dilution, disk diffusion and AATCC 100 assays were performed and the bi-layer dressings exhibited strong antibacterial activity (against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosaand Escherichia coli) and antifungal activity against 4 Candidaspecies. Viability of the fibroblast cells on the obtained structures was evaluated by alamar blue and live/dead assays that confirmed appropriate cyto-compatibility of the nanofibers. Therefore, biocompatible double-layered constructs with strong antimicrobial, antioxidant and water absorption capabilities would be promising as potential wound dressings.

The main objective of this study was to prepare a hybrid three-dimensional scaffold that mimics natural tendon tissues. It has been found that a knitted silk shows good mechanical strength; however, cell growth on the bare silk is not desirable. Hence, electrospun collagen/polyurethane combination was used to cover knitted silk. A series of collagen and polyurethane solutions (4%–7% w/v) in aqueous acetic acid were prepared and electrospun. According to obtained scanning electron microscopy images from pure collagen and polyurethane nanofibers, concentration was set constant at 5% (w/v) for blend solutions of collagen/polyurethane. Afterward, blend solutions with the weight ratios of 75/25, 50/50 and 25/75 were electrospun. Scanning electron microscopy images demonstrated the smooth and uniform morphology for the optimized nanofibers. The least fibers diameter among three weight ratios was found for collagen/polyurethane (25/75) which was 100.86 ± 40 nm and therefore was selected to be electrospun on the knitted silk. Attenuated total reflectance–Fourier transform infrared spectra confirmed the chemical composition of obtained electrospun nanofibers on the knitted silk. Tensile test of the specimens including blend nanofiber, knitted silk and commercial tendon substitute examined and indicated that collagen/polyurethane-coated knitted silk has appropriate mechanical properties as a scaffold for tendon tissue engineering. Then, Alamar Blue assay of the L929 fibroblast cell line seeded on the prepared scaffolds demonstrated appropriate viability of the cells with a significant proliferation on the scaffold containing more collagen content. The results illustrate that the designed structure would be promising for being used as a temporary substitute for tendon repair.

In this study, electrospun nanofibers of polyurethane were prepared utilizing a new solvent system made of chloroform/methanol. Also, we planned to assess effects of four important parameters on diameter of electrospun polyurethane nanofibers using Artificial Neural Networks (ANNs). The parameters investigated included flow rate of syringe pump, distance of spinneret to collector, applied voltage and concentration of polymer solution. Diameter of obtained electrospun nanofibers was measured using scanning electron microscopy (SEM). Results showed that flow rate and distance had reverse relation with fiber diameter, while applied voltage and concentration of polymer solution directly affected the diameter. Also, polymer concentration was shown to be the dominant factor here.