Showing 4 results for Mottaghitalab
Faezeh Mottaghitalab, Seyed Shahryar Arab, Jafar Mohammadian,
Volume 7, Issue 2 (9-2016)
Abstract
Bacteriorhodopsin (bR) is a membrane protein that acts as a light-driven proton pump in Halobacterium salinarum. This protein contains seven transmembrane α-helical subunits, helices A–G, one beta-sheet and a retinal chromophore. Studies show that bR have the property of absorbing the microwave. Among several methods molecular dynamics simulation (MD) is the most systemic approach. With this method we can study structural changes and dynamic of macromolecules. In this project, we use modeling and molecular dynamic simulation. To obtain more accurate structures after the equilibration a 15 ns MD simulation was done. After that, in order to find the effective sites of microwave absorption on bR a production run was performed with applying electric field in the time intervals of 786 ps that is equal to one sinusoidal frequency at microwave spectrum. At last, conformational changes under effect of sinusoidal wave has been assigned the effective sites of microwave absorption in the protein. Our study shows that microwave in the frequency of 8 GHZ and the time interval that mentioned above, cannot make significant changes on the protein. In the other hand, we have seen some reversible changes in Beta-sheet and D, C, B helices.
Volume 12, Issue 3 (9-2009)
Abstract
Objective: Tissue engineering is an (interdisciplinary field that applies polymeric scaffolds to control tissue formation in three-dinemtion (3D). The scaffold provides the microenvironment (synthetic temporary extracellular matrix) for regenerative cells, supporting cell attachment, proliferation, differentiation, and neo tissue genesis due to their suitable chemical, physical and biological structures. In this study, chitosan/poly (vinyl alcohol) (CS/PVA) was exploited as scaffold for nerve regeneration.
Materials and Methods: Electrospinning was used to fabricate CS/PVA nanocomposites for U373 cells seeding and proliferation. Electrospinning is a versatile and simple method to fabricate non-woven thin layer fibers from polymeric solutions. Consequently, the biocompatibility of CS/PVA nanocomposite was evaluated using biological assays and cell attachment study.
Results: Results indicated that CS/PVA nanocomposites with 15/85 proportion shown an almost homogenous network of the electrospun fibers and confirmed that they can be knitted in meshes and improve U373 cells proliferation and cell attachment.
Conclusion: The nano-sized CS/PVA scaffolds are nontoxic and biocompatible which can promote proliferation of U373 cells and their appropriate adhesion to nanocomposite for improved peripheral nerve regeneration.
Volume 12, Issue 4 (10-2010)
Abstract
Objective: Nowadays, as the field of neural tissue engineering advances, the fabrication and application of combined structures open a new window of research for the regeneration of nervous system injuries. In this study, chitosan/poly(vinyl alcohol)-carbon nanotube nanocomposites has been exploited as scaffolds.
Materials and Methods: Electrospinning was used to fabricate chitosan/poly(vinyl alcohol)-carbon nanotube scaffolds. Raman spectroscopy and scanning electron microscopy (SEM) was used to evaluate the chemical and physical structure of the electrospun scaffolds. Then, the biocompatibility of the scaffolds was evaluated using MTT assay and Neutral red assay.
Results: The results showed that the chitosan/poly(vinyl alcohol)-carbon nanotube nanocomposites have suitable structural and morphological aspects for human brain-derived cells growth and proliferation. Therefore, the cells could maintain their usual morphology while adhering to the surface of the nanocomposites due to an appropriate biocompatibility of the scaffolds.
Conclusion: Chitosan/poly(vinyl alcohol)-carbon nanotube nanocomposites could enhance the proliferation of human brain-derived cells due to their proper structure and biocompatibility.
Volume 23, Issue 2 (Spring 2020)
Abstract
Aims: Despite the efficacy of current therapies against HIV-1 infection, these methods are not a permanent treatment because they cannot prevent the return of viremia from latent cell reservoirs. On the other hand, the virus may become resistant to these drugs. Therefore, providing safer and more effective therapeutic strategies, such as inhibition of genes by siRNA, is essential. The successful therapeutic application of siRNAs requires an efficient delivery system to target cells.
Materials & Methods: In this study, a specific siRNA was designed against the HIV-1 nef gene. Then a stable HEK293 cell line expressing HIV-1 nef was developed and after fabrication and evaluation of superparamagnetic iron oxide nanoparticles (SPION) coated with trimethyl chitosan, the efficiency of nanoparticles for delivering siRNA into the cells and inhibition of nef gene was investigated.
Findings: Iron oxide nanoparticles (spherical-shaped with an average size of 85nm and the average zeta potential of +29mV) were significantly effective in transporting siRNA into HEK293 cells compared to control groups and at the same time had low toxicity to the cells. In addition, SPION-TMC containing anti-nef siRNA inhibited about 85% of the expression of this gene in stable cells (compared to control cells).
Conclusion: The optimized SPION-TMC nanocarriers can be used as a promising approach in HIV-1 infection therapy. However, pre-clinical in vivo evaluation of the drug/siRNA delivery system efficiency remains to be conducted.
