Showing 6 results for Fibers
S. Amiri and S. H. Amirshahi,
Volume 26, Issue 2 (1-2008)
Abstract
The reflectance factors of transparent fibers, free delustering agent, are predicted by geometric as well as Kubelka-Munk models.
Transparent fibers are simulated by a net of glass capillary tubes containing different solutions of dyestuffs. Based on the results, prediction of the reflectance factor of capillary net by geometric model is relatively better than those obtained from Kubelka-Munk model. However, the geometric model suffers from a complex and massive computation process. Generally speaking, the geometric model performs better for dark transparent samples due to the ignorable internal scattering phenomena. On the other hand, the Kubelka-Munk model provides better results for light samples, where the geometric model fails in acceptable prediction.
S. Nikbakht Katouli, A. Doostmohammadi, F. Esmaeili,
Volume 35, Issue 1 (6-2016)
Abstract
The aim of this study was to fabricate carbon nanotube (CNT) and bioactive glass nanoparticles (BG) (at levels of
5 and 10 wt%) incorporated electrospun chitosan (CS)/polyvinyl alcohol (PVA) nanofibers for potential neural tissue engineering applications.The morphology, structure, and mechanical properties of the formed electrospun fibrous mats were characterized using scanning electron microscopy (SEM) and mechanical testing, respectively. In vitro cell culture of embryonal carcinoma stem cells (P19) were seeded onto the electrospun scaffolds. The results showed that the incorporation of CNTs and BG nanoparticles did not appreciably affect the morphology of the CS/PVA nanofibers. The maximum tensile strength (7.9 MPa) was observed in the composite sample with 5 %wt bioactive glass nanoparticles. The results suggest that BG and CNT-incorporated CS/PVA nanofibrous scaffolds with small diameters, high porosity, and promoted mechanical properties can potentially provide many possibilities for applications in the fields of neural tissue engineering and regenerative medicine.
M. Shamsi, N. Nezafati, S. Zavareh, A. Zamanian,
Volume 35, Issue 1 (6-2016)
Abstract
Ternary (%mol) (64SiO2-31CaO-5P2O5) system of sol-gel derived bioactive glass fibers was prepared by electrospinning method. X-ray Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nitrogen adsorption test (BET) analyses were performed to investigate the phase and chemical group of the composition, morphology of the surface and specific surface area of the fibers, respectively. SEM observations confirmed that the fibers were nano size. The amorphous nature and the presence of silanol groups in the composition were confirmed by XRD and FTIR, respectively. Apatite formation and biodegradability of the fibers were studied using various analyses after different days of soaking in simulated body fluid (SBF). The results affirmed the presence of apatite layers on the surface of the fibers. Cell culture evaluation indicated that MG-64 human osteoblast-like cells were attached and spread well on the surface. Furthermore, cell viability and cell growth demonstrated that the cells were grown and reproduced well on the fibers.
M. Mirhaj, M. Mahmoodi, A. Shybani,
Volume 36, Issue 4 (3-2018)
Abstract
In this research, keratin (Kr)/ poly caprolactone (PCL)/ hydroxyapatite (HA) scaffold was made by electrospinning method. Then, the effect of HA nanoparticles on properties of scaffold B (Kr 33%, PCL 50% and HA 17%) and scaffold A (Kr 40% and PCL 60%) were studied. The surface morphology, functional groups on the surface of samples, porosity, and specific surface area were evaluated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrophotometer (FTIR), liquid displacement method, and BET test, respectively. The mean diameter of fibers in samples A and B was measured 184 nm and 108 nm, respectively. Results showed that the specific surface area in scaffolds with HA nanoparticles was almost 2 times higher than that of the scaffold without HA. The biodegradability of scaffolds was examined in phosphate buffer solution (PBS) and the results showed an increase in the weight loss percentage of the scaffold B. The cell viability and adherence of osteosarcoma cell line (Saos-2) on the scaffold surface was observed via MTT assay and the results showed an increase in cell growth on PCL/Kr scaffolds with HA nanoparticles. Thus, scaffolds containing HA nanoparticles can be a good choice for tissue engineering applications.
N. Poursharifi, D. Semnani, P. Soltani, S. Amanpour,
Volume 38, Issue 4 (1-2020)
Abstract
In this study, seven-layer nanofiber structures consisting of polycaprolactone/ chitosan polymers loaded with methotrexate and 5-fluorouracil anti-cancer drugs, for controlled drug delivery, were produced and evaluated. For this purpose, the second, fourth and sixth layers were loaded with drug and placed between the drug-free layers. The surface morphology of drug-free and drug-loaded nanofibers was investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR) was used to study their chemical structure. The drug release rate in phosphate buffered saline (pH=7.4) and the released drug concentration were measured by spectrophotometry. Mechanical properties of single- and multi-layered samples were also investigated. SEM images showed formation of uniform and beadless fibers. FTIR spectrum confirmed presence of the drugs in the polymer mixture with no interaction. It was found that by increasing the chitosan content, a brittle structure with decreased elongation is formed. The release behavior of methotrexate and 5-Fluoracil drugs in neutral pH environment for 26 days was evaluated and the results exhibited a slow and sustained release.
S. Torabi, S. Khorshidi, A. Karkhaneh,
Volume 39, Issue 2 (8-2020)
Abstract
For many years, dexamethasone has been used as an anti-inflammatory drug and is still one of the safest glucocorticoids for treating various diseases. Due to the wide range of the side effects of this drug, it is essential to find a suitable delivering system for reduction in dosage with increased effectiveness. Electrospinning is one of the fiber fabrication methods which is widely used to develop drug carriers due to its ability to load various drugs and biological components and control their release. In this research, neat poly (lactic acid) electrospun fibers and dexamethasone loaded fibers were prepared. To evaluate the effect of polymer concentration on morphology, mechanical properties and drug release profile of the resulting fibers, three polymer concentrations of 10%, 14% and 18% w/v were processed. Thereafter, 5% w/v dexamethasone was added to solutions. The scanning electron microscopy images were investigated to obtain the average diameter of fibers and the average area of pores in each sample. In neat samples, by moving from 10% to 18% composition, the average diameter of the fibers increased by 63.21%. However, in drug loaded samples this increased by 51/19%. After evaluating mechanical properties, an increase of 81/34% in Elastic modulus by moving from 10% to 18% composition was observed. Moreover, the ultimate strength increased by 68/021% when increasing the polymer concentration from 10 to 18%. Drug release from the electrospun samples was continued up to 7 days. Linear release was observed in 10% and 14% compositions. The drug release pattern of these samples was of zero order. Considering the importance of zero order release in different applications of dexamethasone, these delivering systems could be useful. The maximum drug release rate belonged to 14% composition (0.044 1/h).
