فهرست مطالب maryam yousefzadeh

Vascular tissue engineering offers innovative solutions to the vascular replacement problems, especially low diameter grafts. Electrospinning is a cost-effective and versatile method for producing tissue engineering scaffolds. Although this method is relatively simple, but at theoretical level the interactions between process parameters and their influence on fiber morphology are not yet fully understood. In this paper, the aim was to find the optimal electrospinning parameters to obtain the smallest fiber diameter by Taguchi’s methodology for vascular tissue engineering applications.

The scaffolds were produced by electrospinning of a polyurethane solution in dimethylformamide. Polymer concentration and process parameters were considered as effective factors. Taguchi’s L9 orthogonal design was applied to the experiential design. Optimal conditions were determined using the signal-to-noise (S/N) ratio with Minitab 17 software. The morphology of the nanofibers was studied by an SEM. Then, human umbilical vein endothelial cells (HUVECs) were cultured on the optimal scaffolds to investigate cellular toxicity of the scaffolds and cell adhesion.

The analysis of experiments showed that polyurethane concentration was the most significant parameter. An optimum combination to reach the smallest diameters was obtained at 12 wt% polymer concentration, 16 kV of the supply voltage, 0.1 mL/h feed rate and 15 cm tip-to-distance. The average diameter of the nanofibers was predicted in the range of 242.10 to 257.92 nm at a confidence level of 95%. The optimum diameter of the nanofibers was experimentally 258±30 nm, which is in good agreement with the estimated value of the Taguchi’s methodology. Cell viability was also reported to be 88.59% and the cells showed good adhesion to the scaffold. These scaffolds can show promising results in mimicking the extracellular matrix and thus in vascular tissue engineering.

Food packaging as a protective layer is one of the most important factors that play a key role in providing healthy food. The aim of this study was to provide a novel paper packaging material by coating with a new dispersion barrier coating based on a mixture of soy protein isolate (SPI) and polyethylene wax (PE-wax) emulsion. For this purpose, mechanical properties, water absorption resistance and oxygen permeability of the specimens were investigated. The results indicated that although the tensile strength of coated paperboards decreased with the addition of PE-wax, there was no significant difference between the SPI-coated paperboards and 30% PE-wax coated ones, and 50% PE-wax coated paperboards showed only a decrease of 6% compared to SPI-coated ones. With increasing the share of PE-wax in the coating formulation, oxygen permeability increased in the coated paperboards but water absorption and water vapor permeability decreased dramatically.

In this study Poly vinyl alcohol (PVA) and cellulose nanocrysrals (CNC) composite nanofibers were prepared by electrospinning process. To dissolve PVA, the deionized water was used due to environmental friendly of PVA. The design of experiments (DOE) was done by the Taguchi method using the Minitab for optimization of electrospinning. Polymer concentration was determined in 4, 6, 8 and 10% by solvent weight. Bead-free fibers were produced in 8% PVA concentration. CNC were added to polymer in 0.5, 1, 1.5 and 2% by PVA weight and DOE was applied for Needle to collector distance (cm), polymer concentration (%), polymer feed rate (mh/hr.) and applied voltage (Kv) were defined as variables, again to reach the thinnest fibers. Nanocomposites were soaked in GA 50% concentration for 48 hrs. to prevent nanocomposites decomposition. SEM and FESEM were used for morphological characterization. Diameter of the fibers was analyzed by Image software. Tensile, Modulus of Elasticity (MOE), Tension, Porosity, swelling and dissolving of nanocomposites were examined. Chemical reactions were traced by FTIR. Fibers with 87±16 nm in diameter were achieved in 0.5% CNC, 22 KV, 0.3 ml/hr. and 20 cm. Swelling and and solubility of nanocomposites were significantly improved by GA. FTIR spectra shows hemiacetal bounds produced during GA soaking. MOE and tensile were improved by CNC addition meanwhile tension and porosity were decreased. Same results were obtained for GA soaked nanocomposites.

There is an increasing demand for tissue-engineered vascular grafts (TEVGs) with long term effectiveness in order to replace or bypass the diseased vessels. Ideal TEVGs should be biocompatible, bloodcompatible and have resistance against aneurysm dilation as well as being easily implantable in the body. Tissue engineering field provides an opportunity for designing and fabrication of ideal synthetic grafts, and so far, researchers have studied several materials and methods for this aim. For example, some TEVGs have been made from decellularized natural tissues, biopolymers, and biodegradable synthetic polymers. However, the researchers still encounter some challenges including true mimicking the mechanical properties of natural tissues and enough neo-tissue ingrowth. Electrospinning is a conventional technique that has a great potential to solve these problems. In this paper, the performed studies on the fabrication of electrospun vascular scaffolds have been reviewed.

There is an increasing demand for tissue engineered vascular grafts (TEVGs) with long-term effectiveness in order to replace or bypass the diseased vessels. Ideal TEVGs should be biocompatible, blood-compatible and have resistance against aneurysm dilation as well as being easily implantable in body. Tissue engineering field provides an opportunity for designing and fabrication of ideal synthetic grafts, and so far, researchers have studies several materials and methods for this aim. For example, some TEVGs have been made from decellularized natural tissues, biopolymers and biodegradable synthetic polymers. However, the researchers still encounter with some challenges including true mimicking the mechanical properties of natural tissues and enough neo-tissue ingrowth. Electrospinning is a conventional techniques that has a great potential to solve these problems. In this paper, the performed studies on fabrication of electrospun vascular scaffolds have been reviewed.
The English abstract is translate of the Persian one. But, unfortunately, it has not 150 words, while the Persian abstract has 180 words.