Sharif Digital Repository

In this research, fabrication of a mediator free nano-biosensor for the detection of cyanide has been studied. This biosensor utilizes 75 nm diameter (nano) ZnO particles synthesized with sol- gel method for modification and immobilization of Horseradish peroxidase (HRP). Cyanide plays inhibitory role in decomposition of H2O2 while HRP plays catalyst role in this reaction. Cyanide inhibits enzyme activity thorough binding with enzyme active sites and result in decreasing electrical current in electrochemical decomposition of H2O2. Amperometery response of biosensor shows linear relation between inhibition percent and cyanide concentration in range of 3µM - 24µM with detection limit of 0.62µM... 

Nowadays , application of enzymes as biocatalysts in wastewater treatment processes is increasing. It is economically important to reuse enzymes and increase their stability in these types of processes. Therefore, was immobilization of enzymes and using them in wastewater treatment have a great importance.In this project, Horseradish peroxidase enzyme, whose effect on phenol removal reactions in other studies has been proven before, was immobilized on the alginate-coated magnetic nanoparticles, to investigate the effect of immobilization on the stability and function of this enzyme for phenol removal. The enzyme was immobilized at the temperature of 25 ° C and pH = 8, according to the data... 

In this project during 2 sections the synthesis and application of nanomaterials based on carbon nanotubes and graphene oxide for immobilization of Glucose oxide and Horseradish peroxidase enzymes for construction of effective biosensors were investigated. In section 1, we introduce a new nanomaterial in which TiO2-coated carbon nanotubes were functionalized with amine groups (NH2-TiO2-CNTs). This nanomaterial was fixed on a glassy carbon electrode surface and then its ability for direct electron transfer of Glucose oxidase (GOx) and Horseradish peroxidase (HRP) on the modified electrode was investigated. The direct electrochemistry of immobilized GOx and its electron transfer parameters at... 

The treatment of water effluent from alcohol industries is among the most challenging industrial wastewater treatments. The challenge mainly arises from the high capacity of organic compounds allowing the growth of microorganisms and pollutants. Brown color of the wastewater also contributes to this phenomenon; it absorbs more sunlight which then reduces the oxygenation of water and thus adversely affecting the aquatic life. Moreover, the acidity of the wastewater decreases the pH level of agricultural soils, so its quality Thus, distillery wastewater, without any treatment can pose a serious threat to the environment. In our study, we investigate the decolorization of molasses wastewater... 

In this project an enzymatic peroxidase biosensor based on two naono structured material 1-Polyaniline nananofibers 2-Polyethylene glycol-Poly citric acid copolymer was studied for phenol detection.Polyaniline nanofibers and poly ethylene glycol-poly citric acid copolymer were synthetized by chemical polymerization.Electrochemical behaviors of these biosensors were studied using cyclic voltammetry (CV) and amperometric techniques. The amperometric response of the coated electrodes is highly stable with 92% of the initial activity remaining after 5 determinations. These phenol biosensors show an oxidation peak at 0.55V. The amperometric response for phenol biosensor based on Polyaniline... 

Effective parameters on decolourization of Sumifix Black B or Reactive Black 5 (RB5) by the extracted peroxidase from Coprinus Cinereus NBRC 30628 in a bioreactor have been reviewed in this master thesis. These parameters were such as hydrogen peroxide concentration, pH of dye solution, enzymatic activity and hydraulic retention time. All of these parameters were optimized in such condition that enzyme solution was added to bioreactor at the initial time of reaction. Optimum concentration for hydrogen peroxide, pH, dye concentration, and hydraulic retention time in above mentioned condition of reactor were 96.1 mM, 8, 40 ppm, and 60 min, respectively. It is worth to note that the higher... 

In recent years, the biodegradation of micro-contaminants using enzymes has attracted the attention of many researchers in the field of environment and health. Micro- and nano-scale environments play an important role in enzymatic catalysis that directly affects the activity and stability of enzymes. Therefore, setting a nanoscale environment for enzymes is very important, especially in liquids with undesirable properties (such as pH, temperature, toxicity, etc.) in this work, a method proposed in which the pH and the substrate concentration are regulated for enzymatic catalysis using a metal-organic framework, consisting of Glucose Oxidase (GOx) and Horseradish Peroxidase (HRP) immobilized... 

Growth factors play an important role in tissue repair and regeneration including articular cartilage tissue. Direct injection of growth factor is a common practice in clinics. However, it has been shown that this method is not very effective and, in some cases, induces some side effects. Moreover, incorporation of this valuable signals in systems where they are quickly released and washed out is not effective as well. Thereby the aim of this study was to design and fabricate an efficient system to effectively deliver growth factors for cartilage tissue engineering. The designed system is an injectable, in situ forming hydrogel, based on hyaluronic acid (HA) as a biocompatible and attractive... 

Levofloxacin has been widely used in recent years as an antibiotic in the treatment of various bacterial infections. This drug compound is known as a newly emerging contaminant. In this study, the degradation of this pollutant has been investigated using advanced oxidation processes, biological process, and a combination of advanced oxidation-biological processes. In order to evaluate the degradation of levofloxacin with advanced oxidation processes, an electrochemical process was used. Advanced oxidation processes were carried out to optimize initial concentration parameters of the contaminant (5-15 milligrams per liter), electrolyte concentration (2.5-10 grams per liter), and current... 

Enzymes, the nanometric biocatalysts that play a key role in biochemical reactions of living cells and bio-organisms, offer various applications including biosensing, bioremediation and chemical synthesis. A simple bio-conjugation procedure to surround a single horseradish peroxidase (HRP) enzyme molecule with dendritic polyester macromolecules (Polyester-32-hydroxyl-1-carboxyl bis-MPA Dendron, Generation 5) was proposed in this project. The characterization of resultant nanoparticles entitled HRP dendrozyme, was performed by TEM, DLS, GPC and FTIR spectroscopy. The results showed that HRP nanoparticles were spherical in shape and have an average size of 14 nm in diameter. Furthermore,...