Sharif Digital Repository

The purpose of this reaserch is to create a context in production of Bone Morphogenetic Protein-2 with more effective properties in Bone healing in Iran. Because of demand Of this protein in medical field it could cause an evalution in bone healing. The first section of this reaserch was the Construction of new recombinant plasmid carrying bone morphogenetic protein gene that was title of this thesis. First total RNA was extracted from ostosarcoma cancer cell line MG-63 followed by cDNA synthesis.For amplifying of the mature region of protein a pair of primer with tow restriction site was designed. After Success in PCR and obtaining PCR product with size of 343bp it transferd to vector... 

Nerve repair plays a very prominent and significant role among the efforts that have been made to integrate the concepts of tissue engineering in strategies to repair almost all parts of the body. This is partly due to the complexity of the nervous anatomy system and its function as well as the inefficiency of conventional repair methods that are based on a component of biomaterials or cells alone. Studies show that electrical stimulation can enhance the nerve regeneration process; so the use of conducting polymers has attracted much attention for the construction of neural tissue engineering scaffolds. In this study, the electrical properties of neurons and the effects of electrical... 

Hydrogels are polymeric three-dimensional networks able to swell in the presence of an aqueous medium. Hydrogels from natural proteins and polysaccharides are ideal scaffolds for tissue engineering since they resemble the extracellular matrices of tissue comprised of various amino acids and sugar-based macromolecules.The biocompatible and biodegradable hydrogel scaffolds are promising materials for tissue engineering. Here, we report a new class of hydrogels derived from oxidized alginate (OA) and gelatin. The prepared oxidized alginate was shown to be efficient in crosslinking gelatin, leading to hydrogel formation. The effect of degree of oxidation and concentration of OA on the mechanical... 

The heart stoke which happens due to an obstruction in the coronary artery can result in the presence of a dead part on the heart muscle called Myocardial Infarction (MI). MI can lead to next heart strokes and even the death of the patient. So far, a great number of biomaterials consisting of natural and synthetic polymers and Extra Cellular Matrix (ECM) of human body have been recommended for being used in tissue engineering approaches aiming to rehabilitate the infarcted site. The use of ECM is recommended for mimicking the microenvironment of the body as much as possible which can be very helpful in proliferation of the cultured cells. In this project, we fabricated a composite... 

Once damaged, articular cartilage has very little capacity for spontaneous healing because of the avascular nature of the tissue. Although many repair techniques have been proposed over the past decades, none has successfully regenerated long-lasting tissue to replace damaged cartilage. Tissue engineering have recently demonstrated tremendous approaches for regeneration of cartilage tissue lesions. Tissue engineering is based on three principles: cells, scaffolds for cell adhesion and growth factors. Three-dimensional biodegradable scaffolds play an important role in tissue engineering. In this study, novel cross-linked hybrid chitosan/ECM scaffolds were prepared for articular cartilage... 

Cartilage is an avascular tissue, having limited ability to repair itself. Since the methods for treatment of cartilage defects have been not effective, in recent years, new therapies based on tissue engineering are considered.This paper reports on the development of porous microcarriers composed of acellular matrix of cartilage and natural polymer chitosan. Microcarriers were prepared by electrospray method. Results of mechanical tests, SEM imaging, water uptake behaviour, biodegradation test, and MTT assay demonstrated that the microcarriers composed of 2% (wt) chitosan and 1% (wt) ECM has the best potential for growth and proliferation of primary chondrocyte cells. These results... 

Following heart coronary artery occlusion, heart stroke (HS) happens which leads to the creation of a dead zone on heart tissue named Myocardial Infarction (MI), the presence of which on a patient’s heart will result in succeeding HSs and the death of the patient. In this study, porous microcarriers capable of being utilized in cardiovascular tissue engineering is fabricated using a mixture of myocardium ectracellular matrix (ECM) and Chitosan (Cs). Results of Elasticity tests, SEM images, swelling behavior, biodegradability test, and cell proliferation assay showed that the scaffold consisting of 3.5% (w/w) Chitosan and 0.66% (w/w) ECM has the best potential in providing cardiovascular... 

Cardiovascular disease is responsible for a majority of health problem in developing countries. Heart diseases are the leading cause of death in the United State with approximately 40% of the death occurs by heart failures and coronary artery defects. Myocardial infarction is one of the diseases that occurs by coronay artery blockage. Cardiac tissue engineering (CTE) is an emerging field that holds great promise towards the development of innovative treatment strategies for heart disease. There are two common scaffolds for CTE, electrospun fiber mats and hydrogels. Although fibers are known as 3D environment for cells, they actually act as a 2D surface, because of lack of cell infilteration.... 

The the nervous system as a most comlicated body system , plays an important and vital role for the body systems. damage to the peripheral nervous system result in nervous system disorders which claissified to Neuropraxia, Axonotmesis and Neurotmesis based on damage itensity. tissue engineering considered as one of the repairing nervous damage way, which by creating 3D substrat (scaffold) with proper physical structure, increses possibility of adhesion, growth and proliferation of cells to increase regeneration rate of damaged nerve. in this study, a combination of dual-electrospinning and rolling the spun film used to preparate a nerve guidance conduit (NGC) based on gelatin, PCL and... 

Methods that has been used for articular defects are faced with many limitations, so new therapies based on tissue engineering were taken into consideration in recent years. However, tissue engineering also encounters challenges regarding optimal scaffold construction and suitable cell source selection. Mature harvested chondrocytes are limited in number and may lose their chondrogenic potential in several cultures, leading to dedifferentiation. In addition, using stem cells also presents unique challenges associated with them, among which hypertrophic differentiation is the most substantial problem. Choosing the appropriate biomaterial similar to the cartilage structure with sufficient... 

This research studies a 3D channeled myocardium scaffold with computational fluid dynamics. It proposes a mathematical model to evaluate the impact of oxygen carriers and scaffold geometry on cell growth in a 3D cardiac construct. The modeling results show that using 5.4% perfluorocarbon oxygen carrier (PFC) has increased cardiac cells density 15% of the initial seeded cells comparing to pure culture medium without PFC supplementation. Effects of the scaffold geometry on cell density in the construct were examined by increasing channel numbers and changing the construct length. The results show that increasing channel numbers (by 50% decreasing channels diameter and wall to wall spacing) the... 

In this research, fabrication of a mediator free nano-biosensor for the detection of cyanide has been studied. This biosensor utilizes 75 nm diameter (nano) ZnO particles synthesized with sol- gel method for modification and immobilization of Horseradish peroxidase (HRP). Cyanide plays inhibitory role in decomposition of H2O2 while HRP plays catalyst role in this reaction. Cyanide inhibits enzyme activity thorough binding with enzyme active sites and result in decreasing electrical current in electrochemical decomposition of H2O2. Amperometery response of biosensor shows linear relation between inhibition percent and cyanide concentration in range of 3µM - 24µM with detection limit of 0.62µM... 

Myocardial infarction (MI) is one of the diseases caused by the temporary or permanent cramp of major coronary arteries. Due to this blockage, blood flow to the heart's myocardial tissue is greatly reduced and finally the person suffered from a Heart stroke (HS). Heart tissue engineering is a promising approach, based on the combination of cells and suitable biomaterials to develop and create heart-like biological substitutes. Since high cardiac cell density, providing metabolic needs like oxygen and nutrients was a challenge. So creation of blood vessel networks within this type of designed tissue has been considered very much.The purpose of this project is to construct scaffolds with... 

The purpose of this study is to assess the inhibitory effects of an appropriate nanoparticles loaded with gallic acid on the fibrillation of alpha-synuclein. Alpha-synuclein is a major component of protein plaques in synucleinopathies, particularly Parkinson’s disease. Gallic acid (GA, 3,4,5-trihydroxy benzoic acid) is a well–known small molecule which can inhibit the formation of α-synuclein fibrils. For the process of fibrillation, purified protein was incubated at 37◦C and pH 7.2. Fibrillation was analyzed by the standard fibril methods.after that investigated fabricating of gallic acid trapped in the chitosan nanoparticles and gallic acid loaded in chitosan –coated mesoporous silica... 

Enzymes are widely used in industry, however, the expensive cost, low stability, and the limited activity in a certain range of temperature and pH, have limited the usage of such bio-catalists. In addition to increasing and preserving their activity under different conditions, the enzyme immobilization can improve its stability in different pH, temperature values and increase its thermostability, storage stability and the possibility of their recycling. Meanwhile, utilizing the super-magnetic systems could be very helpful as well. For instance, separation of the the magnetic nano-particles like Fe3O4 from reaction system using an external magnetic field is easily possible. In this study,... 

Myocardial Infarction occurs due to sudden blockage in a coronary artery and causes necrosis of myocardial tissue. Since myocardium is unable to self-regenerate, cardiac tissue engineering has become a promising therapeutic approach for MI treatment by restoring heart function via combination of cells, biomaterials and signaling factors. For this purpose, myocardial extracellular matrix (ECM) is an attractive biomaterial providing better biomimetic for cultured cells. In this project, we synthesized an in situ forming hydrogel derived from myocardial ECM and for improving mechanical and electrical properties of ECM hydrogel we added oxidized alginate (OA) with 5% oxidation degree and APTMS... 

Since cartilage has limited self-regeneration, in-situ forming hydrogels can act as an ideal scaffold for cartilage tissue engineering to fill the defect gap due to their ability to homogeneously encapsulate the desired cells, efficient mass transfer and minimally invasive characteristics. In this project, an injectable hydrogel with improved structure by adding silk fibroin (SF) nanofibers and better biochemical properties by employing the cartilage extracellular matrix (ECM) was fabricated. The in-situ forming hydrogel is consisted of different concentrations of ionic crosslinked alginate incorporated with different concentrations of SF nanofibers and 1% w/v enzymatically crosslinked... 

In recent years, many efforts have been made in tissue engineering and new methods for the treatment of cartilage damage, with an emphasis on their non-invasive and less aggressive nature. Meanwhile, injectable and in situ forming hydrogels have been considered as a less invasive nature. On the other hand, lack of enough mechanical properties in these hydrogels is one of their main problem. In this study, gelatin and alginate was used to fabricate hydrogel as interpenetrating network (IPN) hydrogel and silica nano particles were also used to increase mechanical properties in the fabricating of hydrogels. Gelatin is also combined with dopamine in order to induce bio adhesive properties of... 

The nervous system is the most important communication machine in body which regulates the function of other organs. Peripheral nerves in contrary to central nervous system have the potential for regeneration, but regrowth requires proper environmental conditions and supporting growth factors. Tissue engineered scaffolds create a suitable milieu for disconnected axon to regenerate. The aim of this study in the first stage is the fabrication of nanostructured of conductive polymers (graphene and polyaniline) within a bed of gelatin polymer and then conducting some analyses including conductance, degradation rate and tensile test besides morphological analyses of fibers through SEM and... 

After carbon and hydrogen the most existed element in crude oil is sulfur which is appeared as sulfur compound in fossil fuels. Sulfur might be converted to hydrogen sulfide by hydrodesulphurization operation. The increasing demand for sulfur removal has required large improvements in hydrodesulphurization technology.Most hydrodesulphurization processes use fixed-bed reactors, however, there are still some disadvantages with performing hydrodesulphurization in these reactors. The most important one is high exothermic nature of hydrodesulphurization process which cause some problems for catalyst in these reactors and decrease the performance of catalyst. In order to solve the temperature...