Sharif Digital Repository

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... 

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... 

Building complex and functional tissues and organs is very challenging. One of the challenges is building an efficient network of blood vessels that can be used to facilitate the transport of nutrients and oxygen to the host. In addition to using channels for oxygen supply, another solution is to use oxygen-carrying materials. In this study, in addition to designing and simulating scaffolds with multi-scale microchannels, calcium peroxide was used to release oxygen and eliminate hypoxia in the scaffold. Here alginate is used as the main material for scaffolding. In an attempt to build a scaffold using a bio-printer, pluronic acid was also used as a sacrificial material to create canals.... 

Cranioplasty is a surgical procedure for repairing skull defects. This surgery will protect the brain tissue, reduce pain in the lesion site and reduce the psychological burden on the patient. Cranioplasty implants should have distinct characteristics, i.e., high strength for protecting the brain, full coverage of skull defects, resistance to infection, non-expansion with heat, and reasonable price. Titanium implants, bone allografts, hydroxyapatite, and methyl methacrylate are commonly used in this surgery. However, these materials have many disadvantages that limit their use. As a result, biodegradable material and 3D printing technology are the next steps for designing scaffolds according... 

Polylactic acid (PLA) is considered as a great option to be employed as 3D porous scaffold in tissue engineering applications owing to its excellent biocompatibility and processability. However, relatively weak mechanical properties, low degradation rate and inappropriate biodegradability limit its extensive usage. In order to overcome the mentioned challenges, micrometric magnesium (Mg) particles were incorporated into the PLA matrix by the fused deposition modeling (FDM) technique. The effects of various Mg contents (i.e., 2, 4, 6, 8 and 10 wt%) on the mechanical, thermal, structural, wettability, rheological, biodegradability characteristics and cellular behavior of the 3D porous PLA-Mg... 

Skin, the largest organ in the body, presents sophisticated functions for maintaining the structural integrity of the entire body. Skin can regulate the temperature of the body, protect the body against microorganisms, have a sensory function, and produce vitamin-D through UV exposure when in direct sunlight.Due to the self-healing property of skin tissue, skin can be repaired by itself. Nevertheless, if extensive skin loss happens, owing to diabetic ulcers or deep burns, skin will not be able to repair the wound by itself. Therefore, it will lose its functions, and the fabrication of a skin equivalent will be necessary. These skin equivalents will cover the wound, regenerate the native...