Sharif Digital Repository

The heart diseases and in particular coronary artery disease have been vastly increased in recent years. Bypass operation is the major recognized way of this disease treatment however, one third of patients don’t have the suitable autologous vein for this operation. It should be noted that for this operation a suitable conduit with diameter as narrow as possible is needed. On the other hand, usage of synthetic polymers won’t be suitable for this operation due to the coagulation forming. The only way to overcome this problem is the use of tissue engineering with the aid of scaffold and autologous cells with the natural tissue function, which reconstructed the desire tissue causing no... 

The development of novel three dimensional degradable porous scaffolds is of great interest for tissue engineering.silk ibroin has recently received intensive attention as a material for use in fabrication of 3D porous scaffolds beacuse of its excellent biocompatibility, physical and mechanical properties, and easy processibility. However, silk alone has no osteoinductive property and considerebely lower mechanical properties than native bone. In order to overcome this limitation silk fibroin can be combined with other materials.the properties of scaffold can be significantly improved and new features can be endowed by the second ccomposition. The present study deals with fabrication of... 

Treatment of critical-size bone defects caused by sport injuries, accidents, trauma, infection, and osteoporosis remains a major clinical challenge. In order to repair or regenerate large bone defects, bioactive three-dimensional scaffolds play a key role due to their multilevel porous structure, high surface area, enhanced mass transport and diffusion. Many studies reported that macropore diameters greater than 500 µm can lead to vascularized bone tissue. In this study, a hierarchically porous composite scaffold was prepared. Hierarchically porous silk fibroin- bioactive glass composite and fibroin scaffold were fabricated with controlled architecture and interconnected structure with... 

Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. The goal of cartilage tissue engineering is to design a scaffold with proper pore structure and similar mechanical properties to the native tissue. In this study Porous scaffolds prepared from silk fibroin, chitosan and gelatin blends with varying ratio of silk fibroin and gelatin by freeze drying method were characterized for physicochemical, mechanical and biological properties. Among the... 

Recently, some wound dressings have been designed that are expected to enhance the wound healing process and prevent blood bleeding and infection. Polymeric dressings have attracted attention due to their biocompatibility, biodegradability, lack of toxicity, and non-allergenic nature. There is widespread interest in using silk fibroin (SF) for this purpose because of its unique properties. Given these points, we have designed an injectable antioxidant hydrogel wound dressing based on SF and Polydopamine(PDA) modified ZnO nanoparticles. First, ZnO nanoparticles were doped with Cu and then modified with PDA (ZnCuO@PDA). XRD, FTIR, SEM, and TEM characterizations were carried out to confirm the... 

In recent decades, due to the significant growth of implants’ application and considering the infection of the implants as the most momentous factor in implantation failure, study on the controlled drug release and other biologically active agents in modern drug delivery systems has attracted many kinds of research throughout the world and efforts are being made to use regulated drug delivery systems for implantation which is also the purpose of this current scientific work.To achieve this, the anodizing process was used to fabricate titanium oxide nanotubes (TNTs) to increase the absorption capacity of the drug in the implants and these TNTs were formed regularly and uniformly in an organic... 

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... 

Currently, using biocompatible and injectable polymeric microcarriers as one of the efficient methods to transfer cells and active agents has gained much attention for bone regenerative medicine. However, they have some drawbacks such as weak mechanical stability and lack of mineral materials, which are the major ingredients of the bone tissues. Accordingly, it is expected that mimicking the chemical and physical structure of bone tissues could be valuable in their medical applications. Herein, a new porous biodegradable microcarriers (MCs) made of silk fibroin-oxidized alginate-bioactive glass was fabricated by electrospraying method. Response surface methodology (RSM) was used to study the... 

It is known that Fluoride ions strongly affect bone mineralization and formation. In the present study, the engineered bone tissue scaffolds are fabricated using silk fibroin (SF) and flouridated TiO2 nanoparticles. TiO2 nanoparticles are modified by fluoride ions, and different levels (0, 5, 10, 15 and 20 wt.%) of the fluoridated TiO2 nanoparticles (TiO2-F) were subsequently added to the SF matrix through phase separation method to prepare silk fibroin/flouridated TiO2 nanocomposite scaffolds (SF/TiO2-F). Phase structure, functinal groups, morphology and mechanical properties of the obtained scaffolds were evaluated by X-ray difraction method (XRD), Fourier transform infrared spectroscopy... 

In recent years, it is expected that the fabrication of multilayer scaffolds and the use of different methodologies in one product can be a new progressing method in skin substitute production. Accordingly, this project aims to fabricate a bilayered composite scaffold with a combination of hydrogel and electrospinning method. We have tried to prepare a scaffold made of oxidized alginate (OAL), gelatin (G), and silk fibroin (SF) without using corrosive solvents and toxic crosslinking agents as a scaffold and drug delivery system. As different biological, chemical, physical, and mechanical factors play a vital role in the healing process, we have characterized the proposed scaffold via DSC,... 

Articular cartilage is devoid of blood vessels, lymphatics, and nerves which gives it a very limited intrinsic healing and repair capabilities. Being under constant harsh biomechanical environment, makes maintaining the health of articular cartilage a vital principle in having healthy joints. Tissue engineering as a method for regeneration of damaged tissue have attracted a lot of attention. Articular cartilage engineered scaffolds act as a macro scale drug delivery system which in addition to having a good mechanical properties similar to that of cartilage tissue, have to provide a highly porous environment for cell migration and proliferation. The aim of this study is to fabricate a drug...