Sharif Digital Repository

Tissue engineering is a science that tries to create new tissues by using cells, growth factors and appropriate biological materials in order to repair damaged organs and replace parts lost due to various reasons. In this research, the effect of adding mxene sheets on the oxidized alginate-gelatin hydrogel scaffold was investigated. For this purpose, mxene nanosheets were first synthesized by Max phase chemical etching and its synthesis was confirmed by X-ray diffraction spectroscoy, field emission scanning electron microscope, X-ray energy diffraction spectroscopy, Fourier-transform infrared spectroscopy, UV-visible spectroscopy. Then, in order to prepare the scaffolds, different amounts of... 

Cardiovascular diseases are one of the leading causes of death worldwide. Despite significant advances in therapeutic interventions for these diseases, the pathophysiology remains incompletely understood. Challenges in drug evaluation include the lack of appropriate clinical trials, such as conventional 2D cell cultures and animal studies, as well as the absence of model systems that can provide complex and patient-specific cardiac functions for diagnosis. Organ-on-a-chip devices have the potential to mimic the body's response to treatments by utilizing microscale cell culture fluid connections and creating realistic models of human organs of interest. Our objective is to develop a... 

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... 

Wound healing is a complex and regular process. It makes more challenge when the volume of wound exudate becomes uncontrollable. To solve this problem, hydrofiber wound dressings which contain carboxymethyl cellulose fibers are being used. Fast absorption and keeping the moisture in balance specially in chronic wounds, is one of the major features of hydrofiber wound dressings. In this research, which was conducted with the aim of investigating the synergy effect of active glasses and Hydrofiber commercial wound dressing for the healing of skin wounds, especially chronic wounds, the sol-gel method has been used to synthesize bioactive glasses based on borosilicate, replacing a part of CaO... 

The retina, a photosensitive area in the central nervous system, is delicate and intricate. It is susceptible to degenerative disorders such as age-related macular degeneration (AMD), retinitis pigmentosa (RP), Stargardt disease (SD), and glaucoma. These diseases can lead to severe vision loss and ultimately irreversible blindness by causing destruction or dysfunction of different types of retinal cells. Unfortunately, there are no proven treatment strategies to cure or reverse these degenerative disorders. However, cell transplantation therapies may be an alternative to replace distorted cells and improve an individual's vision. Recent clinical outcomes show that transplanted cells in the... 

In this work, we have used a 3D printer and unidirectional ice-templating technique in conjunction, to fabricate a novel composite scaffold to facilitate local osteochondral defects tissue regeneration with a cell-free approach. Using ice-templating to induce radially-aligned porosity formation in type I bovine collagen is known to expedite host cells' migration into the scaffold which their ECM secretion shifts cellular milieu toward that of its neighboring tissue layer. We used numerical analysis to design and optimize appropriate freeze-casting mold, finding the optimum value for pin height and metal slab depth to be 4mm and 14mm, respectively. Collagen content equivalent to 2%w/v was... 

"osteoarthritis" is one of the most common joint diseases. This disease has a close relationship with factors such as aging, weight gain, genetics, mechanical pressures, and severe injuries. Although the mechanism of this disease is not fully understood, inflammation is one of the main causes of its exacerbation and progression. controlling inflammation can greatly help in controlling the disease. One of the common treatment methods for osteoarthritis is intra-articular injection of hyaluronic acid and triamcinolone as anti-inflammatory drug. Hyaluronic acid is the main component of synovial fluid, with its viscosupplementation property, prevents bones from rubbing against each other in the... 

Nowadays, advanced and inexpensive pre-clinical methods for investigating the effects of anti-cancer drugs are expanding. One of the latest three-dimensional laboratory modeling for evaluating the effects of drugs is the use of tumor-on-chip technology, which actually models the physiological system of the body through three-dimensional scaffolds, multicellular cultures, and shaped vascular systems. In this study, three-dimensional culture of cancer cells was performed in the form of spheroids. A chip of U-shaped microstructures with and without gaps was used to trap cells and form cancer spheroids. We simulated the simultaneous effect of drug and oxygen concentration distribution inside the... 

In the last decade, the application of organ-on-chip systems to investigate the effectiveness and side effects of various drugs, modele diseases for different tissues has become noticed a lot because these systems are a promising approach to eliminate animal tests and clinical studies on different people. Current conventional methods for drug testing are expensive, time-consuming, and sometimes unreliable. Various organ-on-a-chip systems have been fabricated in order to mimic the conditions of different native tissues in the human body, but only the blood vessel has been considered in most of them while besides blood vessels, as a source to nourish cells, there are lymph vessels as a sink in... 

Despite the increase in the number of cardiovascular diseases worldwide, the number of new drugs to treat these diseases has been decreasing in the last decade. Current preclinical drug evaluation strategies, which use cell cultures and oversimplified animal models, cannot meet the growing demand for new and effective drugs. In the last decade, the development of microfluidic bioreactors and organ-on-chip systems to improve the drug screening process has been increasing significantly. These systems have shown many advantages over previous preclinical models. Despite all these advantages, keeping the oxygen concentration at the optimal physiological level in microfluidic systems has its own... 

Craniofacial bone defects without scarring are a major clinical issue. These critical defects, which can be caused by infection or fracture, cannot be repaired without surgery. The main goal of skull repair is to protect vulnerable structures such as the brain, or it can be due to the improvement of jaw function and beauty. Tissue engineering can offer a new generation solution. The purpose of this study was to construct and characterise a degradable polymer/ bioceramic composite scaffold with allograft powder used in the craniofacial bone. The complexities of the extracellular matrix of humans can be simulated using 3D bioprinting.In this study, tricalcium silicate (TCS) was first... 

Organ-on-chip microfluidic devices create a three-dimensional and dynamic model that allows researchers to model diseases and test different drug candidates. In this regard, using a lung-on-a-chip microfluidic device, Covid-19 disease was numerically modeled. Initially, the distribution of oxygen concentration in the blood and respiratory membrane in the healthy state; when the respiratory membrane is the only barrier between air and blood; was found and observed that in this case, the length that the blood had to travel to reach full saturation was the same in the alveolar capillaries and the lung-on-a-chip microdevice. Then, to simulate the different phases of the disease, the formation of... 

In this study, a new bioink was introduced for the production of tubular tissue structures for cardiac tissue engineering by bioprinter using the FRESH (Freeform Reversible Embedding of Suspended Hydrogels) method. The novel bioink that we used was a combination of cardiac extracellular matrix (cECM) and oxidized alginate. The cardiac extracellular matrix was used to increase the biomimetic of the printed structures to the actual tissue of the body, and also to create sites for cell adhesion, and to improve cell growth and survival. We used alginate oxide (oxidation degree: 5%) to increase the mechanical properties of the tissue. Alginate oxidation has been due to extracellular matrix (ECM)... 

In this study, chitosan-based nanoparticles were prepared due to their biocompatibility, availability, high loading capacity of drug, stimulus responsive behavior and the presence of active functional groups. Chitosan was chemically functionalized with reactive oxygen species (ROS)-responsive moiety to respond to the oxidative stess and endosomal pH in nerve injuries. To prepare nanoparticles, functinalized chitosan ionically gelated with pH-responsive polyanions with ROS-scavenging properties such as polyacrylic acid and hyaluronic acid. Then, pH- and ROS-responsive nanoparticles were used for selective transfection into reactive astrocytes and axonal regeneration in spinal cord injuries.... 

PMMA bone cement lacks biodegradability and the ability to bond with surrounding bone tissue. Therefore, the development of a new generation of bioactive bone cements that are biodegradable and possess adequate mechanical properties as well as desirable setting time is receiving remarkable interest.In this study, we have developed novel mineral-based bioactive bone cements. Our mineral bioactive bone cements were composed of Calcium Sulfate Hemihydrate, Bioactive Glass, and Tricalcium Silicate. Firstly, a binary system composed of Calcium Sulfate Hemihydrate and Bioactive Glass was optimized based on mechanical and setting behavior. Secondly, Tricalcium Silicate was added to the powder phase... 

Because of the inability of conventional methods to regenerate the infarcted part of the heart, regenerative medicine based on using scaffolds and hydrogels incorporation with cells and biological factors emerges as a promising approach. Micro-structures, especially hollow microcapsules created by the microfluidic system, has received a great deal of attention due to their inspired biomimetic structures, providing complete coverage cells, and preventing an immune response, consequently. This study aimed to use a microfluidic system to fabricate hollow microcapsules and investigate the behavior of rat cardiomyoblast cells (H9C2) along with exosomes within these structures. These structures'... 

Herein, we successfully prepared two types of hydrogels, alginate-beta-cyclodextrin based hydrogel and alginate without beta-cyclodextrin hydrogel in order to use in cartilage tissue engineering. At first, sodium alginate was modified with beta-cyclodextrin ring due to incorporate the kartogenin (KGN) differentiating drug in the hydrogel structure. For confirming the correctness of the modification reactions, H-NMR spectroscopy was used. In the presence of phenolized-ECM, alginic acid, modified alginate with beta cyclodextrin, HRP, H2O2, calcium carbonate, and glucono-delta-lactone (GDL), ECM-alginate-IPN and ECM-modified-alginate-IPN hydrogels were synthesized. Then, the KGN was loaded on... 

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... 

3D bioprinting technology is a promising approach for corneal stromal tissue regeneration. At first, two different concentrations of GelMA macromer (7.5% and 12.5%) were tested for corneal stroma bioprinting. Due to high macromer concentrations, 12.5% GelMA was stiffer than 7.5% GelMA, which made it easier to handle. In terms of water content and optical transmittance of the bioprinted scaffolds, we observed that scaffold with 12.5% GelMA concentration was closer to the native corneal stroma tissue. Subsequently, cell proliferation, gene and protein expression of human corneal stromal cells encapsulated in the bioprinted scaffolds were investigated. Cytocompatibility in 12.5% GelMA scaffolds... 

One of the chief kinds of receptors in cancer angiogenesis is the tyrosine kinase VEGFR-2. This target receptor is presented in both forms; active and inactive. adenosine triphosphate (ATP) residue is the location of deformational change from inactive to active form. Small molecule inhibitors have been designed for various forms of this receptor. In current study, the interaction of small molecular inhibitors including; Regorafenib, Cabozantinib and Thiosanib with dual VEGFR-2 receptor forms was investigated by molecular dynamics with Gromacs software. Cabozantinib and Regorafenib inhibitors had a lower binding energy in interaction with the inactive state however, Thiosanib inhibitors in...