Since collagen is naturally a main extracellular matrix protein, it has been applied widely in skin’s tissue engineering scaffolds to mimics the characteristics of extracellular matrix for proper transplantation of living cells. However, there are challenges that come with application of this natural polymer such as high solubility in aqueous environments which requires further consideration such as chemically cross-linking in order to stabilization. But these treatments also affect its functionality and finally cellular behaviors on scaffold. In this research we evaluated the suitability of collagen nanofibers versus collagen nanoparticles for cell adhesion and viability on glutaraldehyde cross-linked scaffolds. Appling a dual-pump electrospining machine a blend PCL-Gelatin from one side and collagen nanofibers or collagen nanoparticles from the other side were collected on the collector. The fabricated scaffolds were characterized by scanning electron microscopy, contact angle, and mechanical analysis. The cell viability, adhesion and morphology were studied respectively using MTT assay, hoechst staining and scanning electron microscopy. The results indicated significantly improvement of cell viability, adhesion and better spreading on scaffolds with collagen nanoparticles than collagen nanofibers. It seems changes in surface morphology, viscoelastic moduli and swelling ability following cross-linking with glutaraldehyde in scaffold with collagen nanoparticles are still favorable for cellular proliferation. Based on these results, in the case of glutaraldehyde cross-linking, application of collagen nanoparticles rather than collagen nanofibers in tissue regeneration scaffolds will better mimic the extracellular matrix characteristics; and preserve the viability and adhesion of seeded cells.
Fibrinogen plays a necessary role in blood clotting and wound healing. In this study, a new solvent mixture of formic acid/acetic acid with low toxicity was investigated as an alternative solvent for fibrinogen electrospinning. The nanofibers were analyzed by scanning electron microscope (SEM), simultaneous thermal analysis (STA) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that when the ratio of formic acid to acetic acid was 75/25 (v/v) the finest defect-free fibres with diameters ranging from 184 ± 37 to 241 ± 70 nm were obtained. In addition, the average fibre diameters increase with increasing concentration of fibrinogen from 10wt% to 12wt%. It is concluded that solvent mixture consisting of formic acid/acetic acid can be a great solvent for electrospinning of fibrinogen and is able to produce nanofiber structures.
Silver nanoparticles (AgNPs) are considered an appropriate approach to treat the leishmaniasis in terms of the toxicity and resistance of current anti-leishmanial drugs. This study aimed to prepare stable AgNP and their apoptotic effects on the metabolic activity of Leishmania major. AgNPs were prepared with a green synthesis method using Z. multiflora Boiss ([Formula: see text] extract as a reducing and carboxymethylcellulose (CMC) stabilizer agent. The formation and colloidal stability of AgNPs were shown using ultraviolet-visible absorption spectroscopy during an 80-day period. The average diameter of [Formula: see text][Formula: see text]nm and the surface charge of [Formula: see text][Formula: see text]mv were obtained for AgNPs. Furthermore, the toxicity and apoptotic values of AgNPs on Leishmania major were evaluated by MTT assay and flow cytometry, compared with Glucantime[Formula: see text] (meglumine antimoniate) as the current standard medication for leishmaniosis. The results indicated that [Formula: see text] extracts coated AgNPs (Z.M@AgNPs) reached IC[Formula: see text] at a 100[Formula: see text][Formula: see text]g/mL concentration, while Glucantime[Formula: see text] reached this point at a concentration of 4000[Formula: see text][Formula: see text]g/mL. The flow cytometry data revealed that the primary mechanism of death in the promastigotes was apoptosis (35.44% for AgNPs and 32.69% for Glucantime[Formula: see text]). The present findings suggest that Z.M@AgNPs are superior therapeutic agents than Glucantime[Formula: see text] as the positive control group for leishmaniasis treatment. However, further advanced studies are needed to confirm these results.
AbstractThe aim of this study was an investigation on the proliferation rate of normal human epidermal keratinocytes (NHEK) on the cross-linked and uncross-linked fibrinogen/polycaprolactone (Fbg/PCL) nanofibers to determine a suitable scaffold for skin tissue engineering. Nanofibrous scaffolds were prepared by electrospinning of different weight ratios of Fbg to PCL and were analyzed as morphology, surface chemical properties and cytocompatibility by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, respectively. The diameters of the blended uncross-linked scaffolds were in the range of 124±43 nm–209±155 nm. Cross-linking of scaffolds with glutaraldehyde did not make a significant change in the diameter of blended scaffolds in 16 h. Cross-linking also improved the tensile strength and weight loss rate of scaffolds. However, cross-linking demonstrated an unfavorable effect on the attachment and proliferation of NHEK cells. The proliferation study revealed that uncross-linked scaffolds containing 50% and 70% Fbg provide a better environment for the growth of NHEK cells, and can be considered promising scaffolds in tissue engineering applications.
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