Sharif Digital Repository

This study aimed to prepare a type of microcapsule that microencapsulates folic acid and iron at the same time and protects these two substances against environmental and gastrointestinal conditions. Simultaneous release of these two nutrients has dual health properties and improves the efficiency of folic acid microencapsulation. In this study, biocomposites were formed containing alginate, pectin, and carboxymethylcellulose, and the microcapsules were synthesized by the ionization of calcium-alginate ions. Biocomposite optimization mixture with 13 experiments using experimental design software, optimal combination design method based on repopulation separator, restoring folic acid... 

Due to the increased public awareness about the role of food on health, an increased interest of consuming fortified food has grown rapidly. Probiotic bacteria and DHA poly-unsaturated fatty acid are two major bioactive ingredients becoming increasingly popular in food fortification industry due to their beneficial effects. However, high susceptibility of probiotic bacteria during production, maintenance and digestion in acidic and enzymatic conditions of gastrointestinal tract results in decreasing the survivability and therefore reducing health effects in body. Besides, having multiple double bonds in the structure of DHA fatty acid leads to oxidative degradation that produces volatile... 

Recently, diamond nanoparticles have attracted interest for biomedical applications such as drug delivery, targeted cancer therapies, fabrication of tissue scaffolds and biosensors. In the present work, elecrophoretic deposition (EPD) of nanodiamond-bioactive glass-alginate nanocomposite was studied. In vitro bioactivity and biocompatibility of the nanocomposite were evaluated in simulated body fluid (SBF) and by MTT assay. The EPD process was performed under different conditions in order to obtain a uniform coating on the surface of 316L stainless steel substrate. The stability of the suspension was determined via optical sedimentation method and zeta potential analysis. It was found that... 

Burns are one of the most important accidents related to human health. Due to the intense physical and mental complications and high fatality rate associated with them, receiving proper treatment is of paramount importance. The control of infection in wounds would cure and eliminates the effect of wounds and treatment of skin lesions with engineered scaffolds can be an effective method. The purpose of this project is proposing a hydrogel scaffold based on natural polymers of oxidized alginate and gelatin loaded with an herbal drug to control infection and treat burn wounds. For this purpose, the Iranian Oak extract that it's main content is Tanin and PolyPhenolinc materials, was prepared and... 

With the rapid development of biotechnology, peptide and protein drugs are now playing an increasingly important role in therapeutics. Compared with chemical drugs, peptide and protein drugs have some limitations such as low stability and rapid deactivation. Biodegradable and biocompatible polymeric micro carriers have been shown to have a high potential for the delivery of peptides and proteins. Among these polymers, alginate has been widely investigated as a biomaterial. Alginates are natural polysaccharide polymers isolated from brown seaweed. Bovine serum albumin (BSA) loaded calcium alginate microspheres produced in this study by a modified w/o emulsification method. The influence of... 

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,... 

Significant advances in biotechnology have led to the emergence of a cost-effective way with less ethical issues to study disease, organ functions, tumors, and their response to drugs besides studying on animals. Microfluidic devices and organ on a chip (tumor on a chip) were introduced to remove those obstacles. Organ on a chip is a powerful tool for studying different types of tissues and simulating diseases, especially cancers, for biological and medical applications. Organ (tumor) on a chip is considered as a smaller scale of the real organ or tumor and it causes to the real-time study of tissues and their functions more accurately. In this study, to fabricate a droplet-based... 

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... 

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... 

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... 

Three sizes of silica nanoparticles (160±7, 450±10 and 600±25) were sythetized via template-removing method. The synthetized nanoparticles were functionalized with N-(2-aminoethyl)-3-aminopropyl trimethoxy-silane (EDS) to provide a positive charge on the surface of nanoparticles. BET analysis showed that the average pore diameter, surface area and pore volume of nanoparticles were 2.3 nm, 769 m2.g-1 and 0.44 cm3.g-1, respectively. showed that the Amine-functionalized silica nanoparticles were used to enhance the application of alginate polymer for 3D encapsulation of mammalian cells. Incorporating of silica nanoparticles can be suitable for the bead integrity and attachement of mammalian... 

Mammalian cardiac tissue lacks the ability to effectively self-regenerate following severe damage. The application of external therapeutic agents with strong mechanical properties is needed to restore its function. Even though conventional therapies have several challenges and limitations, injectable hydrogels, with minimally invasive, can significantly improve cardiac tissue regeneration. Extracellular matrices are the most appropriate biomaterials for synthesizing cardiac scaffolds. The human amniotic membrane obtained from the amniotic sac is a readily available, abundant, and inexpensive candidate that has been successfully utilized for the clinical treatment of cardiac diseases.... 

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.... 

Cartilage is a connective tissue, whose most important role in the body is to create a surface with a low friction coefficient in order to allow bones to slide on each other without direct contact to transfer loads. Articular cartilage is always under a harsh biomechanical environment and lacks blood, lymphatic and nerve vessels. As a result, it limits the capacity of this tissue to improve and restore itself. According to experimental efforts, cartilage cannot be regenerated spontaneously without the support of healthy subchondral bone. In recent years, the implantation of tissue engineering scaffolds has been considered as an effective strategy for the treatment of osteochondral damage.... 

Nanoparticles have attracted the attention of many researchers because of the distinct physical and chemical properties. Besides the traditional applications in plastic reinforcement, fluid rheological additive, etc., the nanoparticles could be applied to many new fields and high-functional devices. Various chemical methods have been employed for the production of nanoparticles with narrow size distribution, such as co-precipitation, micro-emulsion, electrochemical synthesis, hydrothermal synthesis, sol–gel processing, flame spray pyrolysis, plasma chemical vapor deposition (CVD), hot-soap method and electrospray pyrolysis. But most of them have some problems so that only a few of them... 

One of the major problems in cancer treatment is the side effects of the drugs. Nowadays, scientists are developing smart nanocarriers which used for diagnosis and delivering drugs in order to circulate through blood vessels, pass the immune system, attach to cancer cells and kill them without any side effects. In the first research of this thesis, magnetic nanoparticles were coated by modified alginate and used as smart nanocarriers. Magnetic nanocarrier were sysnthesized based on hydrophobic coating of oleic acid and hydrazine oleate-modified alginate shell. The resulting carrier is pH-sensitive and the alginate shell removes in the low pH medium. DOX was placed between hydrophobic chains.... 

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... 

Quince seed gum is a natural material that was used in Iranian traditional medicine for wound treatment. Alginate is a beneficial biomaterial that has been used in making commercial wound dressings for a long time. In this work, the preparation method and properties of films based on Alginate and Quince seed gum for drug delivery and wound healing have been investigated. According to the obtained results about crosslinking and plasticizing, the suitable condition of synthesis is 0.5% CaCl2 concentration, 2min soaking time, and 13% glycerol in crosslinking solution. In this crosslinking solution, a film with good mechanical properties (tensile strength: 13MPa, elongation: 27.3%, and Young’s... 

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... 

In this research, we developed a drug release system of two biocompatible and biodegradable polymers and biocompatible ceramic nanoparticles. Hydrogels of sodium alginate (SA) were crosslinked using calcium chloride. The SA hydrogels were blended with polyvinyl pyrrolidone (PVP) and mixed with hydroxyapatite nanoparticles (HAP) to make hydrogel nanocomposites in the form of microbeads as drug carriers. Ciprofloxacin was selected as a model antibiotic drug for treatment of bone infection. It was found that SA and PVP form hydrogen bonds and are miscible at whole range of concentrations. Indeed, the SA/PVP blends may be considered as interpenetrating polymer networks (IPNs). HAP nanoparticles...