Sharif Digital Repository

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... 

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... 

Double network (DN) hydrogels are a new interpenetrate polymer network (IPN) that are usually contain about 60-90 % water. Despite of this amount of water, they are though and strong. DN hydrogels comprise of two networks, the first one as the brittle gel, is generally high density crosslinked and the second one, the loose and stretchable network, is loosely crosslinked or even without crosslinking. Therefore, we used cationic polymer, chitosan, and anionic polymer, alginate, as the first networks, therefore, we used sodium phosphate for physical crosslinking of chitosan, and calcium chloride as the physical crosslinking agents for alginate network. Also, poly (vinyl alcohol) (PVA), as the... 

Most natural folate derivatives are highly sensitive to temperature, oxygen and light and their stability depends on food process condition. Alginate and pectin were evaluated for folic acid encapsulation and increasing its stability. By combining them and optimising encapsulation condition the efficiency was enhanced up to 90% . Furthermore, using polymers in combined form caused decrease in folic acid leakage from capsules in acidic condition of stomach. First of all, the time of encapsulation was measured which was 140-180 minutes. In this study the effect of Calcium Chloride concentration on encapsulation was studied. Therefore, two variables were selected which were pectin to algine... 

The enzyme L-asparaginase (L-asparagine amidohydroxylase , EC 3.5.1.1) is utilizable in the treatment of acute childhood lymphoblastic leukaemia. L-asparaginase catalyses the hydrolysis of the amino acid L- asparagines to L-aspartic acid and ammonia. Unlike normal cells,malignant cells which can only slowly synthesize L-asparagine , are killed by lacking exogenous supply. In contrast, normal cells are protected from Asn-starvation due to their ability to produce this amino acid.
In this study , L- asparaginase from E.coli, was immobilized onto a polymeric compound, poly(vinyl alcohol)(PVA) with cross-linking agent glutaraldehyde and calcium alginate beads .. Herein ,with the use of the... 

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... 

Uptake characteristics of alginate microcapsules containing D2EHPA/TOPO for adsorption of uranium from industrial effluent were examined using batch, stirred and column method .stable alginate microcapsules in dried form was developed by immobilizing of D2EHPA/TOPO in porous matrix of calcium alginate. Characteristics of microcapsules were carrying out by destructive chemical analysis, BET, SEM and TG .the synthesized microcapsules showed a good column properties and high selectivity and reusability. In addition, isotherm adsorption of calcium alginate and microcapsules were fitted with frendlich's equation .the microcapsules also demonstrated that, the uptake percentage was constantly high... 

In the past few decades, many attempts have been made to combine the benefits of homogeneous and heterogeneous catalysts. The immobilization of homogeneous catalysts onto the surface of heterogeneous supports is the result of such efforts. In this research, immobilized heterogeneous catalysts were designed and synthesized based on double network hydrogels, which produce from interpenetrating of two biocompatible and biodegradable polymer networks. In order to provide magnetic responsibility and easy separation of catalyst from the reaction mixture, the magnetic nanoparticles were dispersed onto the surface of double network hydrogel. Finally, various metal nanoparticles such as palladium and... 

In the present research the methods and challenges to ocular drug delivery have been investigated with more emphasis on ocular diseases that do not have any approved treatment. Periocular route is a promising alternative to the common routes of ocular drug delivery especially for treatment of posterior eye diseases. Based on barriers for efficient drug delivery to the eye, magnetic drug targeting revealed to be influential to eliminate some obstacles of this route which has not been worked before. It is hypothesized that the particles can pulled into the eye or will be trapped inside the sclera tissue or even if it is not happened, they can stay behind the sclera and magnetic force can... 

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.... 

In this study, Pseudomonas aeruginosa BBRC-10036 was used for lipase production. The organism secreted the enzyme extracellulary. First of all, effect of initial pH of the culture broth on lipase activity was studied in order to determine the optimum condition for lipase production. After production, this enzyme must be separated from culture and after that the enzyme must be purified for using in analysis and industry. Different methods are used for purification of the enzyme. In this research, first precipitation was used and then this lipase has been purified by Ion exchange Chromatography leading to 2.33- fold purification and 11.47% recovery. In precipitation by acetone, maximum... 

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... 

Vitamin C is an essential for the survival of human, animals and plants. Human and most animals can not produce vitamin C in their bodies, thus the need to produce vitamin C as a supplement is necessary. Nowadays, for the industrial production of vitamin C, two Chinese and Rychstyn methods are used, the first method is a two-step method which is accomplished biological and the second method is done chemically. In Chinese method, first step, which is the most important step is production of L-sorbose from D-sorbitol by Gluconobacter oxydans bacteria .Thus, in this study it was attempted to optimize the production of L-sorbose to be used in industrial production of L-ascorbic acid. In... 

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... 

In this thesis, a novel graphene oxide (GO)/sodium alginate (SA)/polyacrylamide (PAM) ternary nanocomposite hydrogel with excellent mechanical performance has been fabricated through freeradical polymerization of acrylamide (AAm) and SA in the presence of GO in an aqueous system followed with ionically crosslinking of calcium ions. Physical and chemical characteristics of the composite were investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling behaviors of the composite hydrogels were investigated under varying conditions of time and pH. The optimized swelling capacity in standard conditions was found to be 1711% per gram of the hydrogel. The... 

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... 

β-galactosidase enzyme is immobilized from Kluyveromyces lactis by Microencapsulation method in various compositions of sodium alginate and Carboxymethyl cellulose. Optimum stabilization was gained at 1.85% sodium alginate, 0.9% carboxymethyl cellulose and 2% calcium chloride through applying Surface response methodology. Yield of immobilization and activity was 54.94% and 65.27%. variation of yield of immobilization versus alginate concentration was a quadratic curve with the maximum. When alginate's concentrations is low, the cavities diameter is great, so the enzyme leaks from capsule while immobilizing. At high concentrations of alginate, despite the smaller cavities, immobilization... 

Probiotics are defined as essential live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. In order to provide health benefits for probiotic bacteria it has been recommended that they must be present at a minimum level of 106 CFU/g of food product or 107 CFU/g at point of delivery or be eaten in sufficient amounts to yield a daily intake of 108 CFU. Several studies have shown that certain strain of lactic acid bacteria, such as Bifidobacterium bifidum and Lactobacillus acidophilus prevent some diseases linked to the gastro-intestinal tract. however, many reports have demonstrated their poor survival and stability. Their survival in the... 

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... 

Microbial proteases are among the most important hydrolytic enzymes and havebeen studied extensively since the advent of enzymology. They are essentialconstituents of all forms of life on earth, including prokaryotes, fungi, plants andanimals.In recent years there has been a phenomenal increase in the use of alkaline protease asindustrial catalysts. Alkaline proteases (EC.3.4.21–24, 99) are defined as thoseproteases which are active in a neutral to alkaline pH range. Cell immobilization is a technique that restricts the free movements of microorganisms in the process and it has a lot of advantages including this fact that biotechnologists’ dream for using continuous system in fermentation...