Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Increasing Doxorubicin (dox) Release From Liposomes(Izmir Institute of Technology, 2019) Hanoğlu, Berçem Dilan; Özdemir, Ekrem; Altun, Zekiye SultanCancer is the second most common cause of death in the world and its incidence is increasing day by day. Doxorubicin (DOX) is an anthracycline group drug frequently used in many cancer treatments including breast cancer. However, free DOX has many harmful side effects and need to be encapsulated into nanocarrier such as liposomes. Although liposomal DOX has many advantages over its free form, liposomal DOX has undesirable side effects such as hand and foot syndrome. In this thesis, it was aimed to develop a more effective liposomal DOX delivery and release systems. Liposomes were prepared with alkaline solutions containing tris, sodium carbonate, ammonium chloride, and ammonium sulfate. DOX loading into liposomes and the percentage of release from liposomes were examined. A loading efficiency of about 80% was achieved, while the release was found to be below 13% at room temperature. The release of DOX was found to be enhanced from liposomes in the presence of ammonia (NH3), whose content was dependent on pH. Temperature was also found an important parameter and enhances DOX release at higher temperatures than the phase transition temperature of the lipid. A two-component liposomal system was proposed where ammonia (NH3) would be released from one liposome and enhance the DOX release from other liposomes. It was found that temperature, pH, and ammonia (NH3) concentration affected DOX release from liposomes. As a result, DOX was successfully loaded into liposomes and ready to study their effect on breast cancer cells.Master Thesis Hydrothermal Preparation of Single Crystalline Ceo2 Nanoparticles and the Influence of Alkali Hydroxides on Their Structure and Optical Behavior(Izmir Institute of Technology, 2009) Kepenekci, Özlem; Eanes, Mehtap; Eanes, MehtapSingle crystalline cerium oxide nanoparticles were synthesized via hydrothermal method by mixing aqueous solution of cerium nitrate [Ce(NO3)3.6H2O] with an alkali base. Several characterization methods were used to identify morphology and crystalline nature such as X-ray Diffraction, Scanning and Transmission Electron Microscopes. This study is divided into three parts. In the first part, some controlling parameters like, that were affecting size and shape of CeO2 nanoparticles, were studied. It was found that size of CeO2 nanoparticles increased when increasing both reaction time and temperature. Alkali base concentration promoted the particle growth. Also, particle morphology was more uniform rather than aggregated in presence of higher concentrated alkali base. When the alkali base type was changed, the use of NaOH produced larger cubic nanocrystals of CeO2 than KOH and LiOH.Second part is related to determine the optical properties of CeO2 nanoparticles. Based on the UV-Vis and Fluorescence Spectroscopy results, size, bandgap and defect level of CeO2 nanoparticles can be easily determined. Nanoparticles in presence of NaOH alkali base were found to produce less defective CeO2 nanoparticles as compared to KOH and LiOH. The last part of this work is to evaluate the shape effect on morphology, size and optical properties of CeO2 nanoparticles. Rod crystals of CeO2 were produced when the hydrothermal synthesis temperature was low (120°C) or when the reaction time was short (1 hour). When the synthesis temperature was higher than 160°C well defined cubic crystals of CeO2 started to form.Master Thesis Production and Characterization of Water Soluble Cdsete Based Core/Shell Nanocrystals and Their Applications in Bioimaging(İzmir Institute of Technology, 2009) Özdemir, Seda; Özçelik, SerdarIn recent years, nanotechnology has become one of the most intensively studied fields. At the nanometer scale, materials have unique electrical, optical, magnetic and chemical properties. They can be used for a wide variety of applications such as electrooptical devices, tagging and medical applications. The goal of this study was to produce water-dispersible alloyed CdSexTe1-x semiconductor nanocrystals, which are suitable to interact with biomolecules. CdSexTe1-x nanocrystals were synthesized by a single step aqueous synthesis method. Monodisperse, CdSexTe1-x nanocrystals with zinc blende structure were obtained in water. Synthesized nanocrystals emit in the range from 528 nm to 620 nm. CdSexTe1-x nanocrystals have 17% photoluminescence quantum yield, after the CdS shell coating the photoluminescence quantum yield increased up to 22%. MTT test and Trypan Blue tests were used to evaluate the toxicity of CdSexTe1-x nanocrystals. MTT measurements reveal that the MCF7 cancer cells are not affected by the nanocrystals at any dosage and exposure condition, but lethal effects are determined at the concentration of 1.0ug/ml for the PC3 cells. The BEAS 2B cells are very sensitive to the nanocrystals and do not proliferate at concentration of 0.5ug/ml. Confocal microscopy studies show that the nanocrystals has ability to penetrate to the cytoplasm of cells.Master Thesis Production of Nano Calcite in Large Scale(Izmir Institute of Technology, 2013) Alıcı, Sezen Duygu; Özdemir, EkremCalcium carbonate (CaCO3) has been used extensively as filling material in various industries in order to improve some mechanical properties of the composite materials and to reduce the product costs. There are mainly two methods for synthesizing CaCO3 crystals: chemical method and carbonization method. The carbonization method is the most appropriate method for nano calcite production. A systematic study was conducted on the synthesis of calcite in nano sizes, homogeneous size distribution, and different morphologies by employing the newly developed small penetration method. The effects of various parameters on the particle size and morphologies such as flow rates of raw materials, concentration, pipe diameter, volumes of stabilization tank and reaction chamber, length in the reaction chamber, stirring rate, and temperature were investigated. Calcite particles of about 100-150 nm were achieved to produce in homogeneous size distributions for the developed method at large scale.Master Thesis Production of Nano Caco3 in Bench Scale by Small Penetration Theory(Izmir Institute of Technology, 2013) Toprak, Görkem; Özdemir, EkremCalcium carbonate (CaCO3) has been used as filling material in various industries such as paint, paper, and polymeric materials. Using filling materials will enhance some of the physical properties of the composite material and decrease the product costs. Especially, the physical properties of the composite materials were enhanced significantly when the CaCO3 is used in nano sizes. CaCO3 can be produced from natural sources by crushing, grinding, and sieving processes, however, calcite obtained from the natural sources are usually in micron sizes and they are not in the desired quality and purity. Here, it was proposed that the dissolution rate of CO2 is the limiting step in CaCO3 crystallization and a small penetration method was developed for the limited dissolution of CO2 in the Ca(OH)2 solution. When Ca(OH)2 was added into the 10 mM CaCO3, zeta potential values of CaCO3 particles were increased from negative to positive value indicating that CaCO3 particles were stabilized in the presence of Ca(OH)2 solution. Rice-like CaCO3 particles were synthesized at the very early stage of crystallization. When crystallization progresses, the high energetic end sites started to dissolve, and the dissolution was progressed through the inside of the particles resulting in hollow calcite particles. BET surface area of hollow calcite particles was found to be 14.75 m2/g. Different parameters such as Ca(OH)2 flow rate, CO2 flow rate, Ca(OH)2 concentration, pipe diameter etc. were studied. Calcite particles in nano sizes, homogeneous size distribution, hollow shapes, and different morphologies were achieved to be produced.Master Thesis Development of a Novel Electrocardiography Sensor Based on a Composite Silver Chloride Nanoparticles and Polyaniline(Izmir Institute of Technology, 2013) Taşcıoğlu, Didem; Özçelik, SerdarThe electrical activity of the heart is detected by electrodes attached to the surface of the skin. These electrodes detect bioelectrical signals in the human body. Physilogical status of heart condition especially cardiovascular diseases and disturbances in the cardiac rthym are recorded by electrocardiography (ECG). Despite the fact that the usage of disposable ECG electrodes in our country is substantial nearly as 70 million in 2010, these electrodes are not fabricated in Turkey. In the scope of this study, it was aimed to develop a novel sensor based on synthesized AgCl/Polyaniline nanocomposites for ECG electrodes. In this study, the production of silver chloride (AgCl) nanoparticles was achieved by the polyol method. ABS (Acrylonitrile butadiene styrene) was used as a supporting material of the ECG electrode. Synthesized AgCl nanoparticles were not easily adsorbed on the surface of ABS. We develop a synthetic chemistry to perform simultaneous synthesis of AgCl nanoparticle and polymerization of aniline on surface of ABS. Polyaniline acts as a chemical linker between the nanoparticle and ABS surface in the same batch reactor. The synthesized composite based on polyaniline and AgCl nanoparticles completely covers the surface of ABS. To evaluate electrodes, we fabricated a disposable ECG electrode and compared it with the disposable electrodes that are commercially available. The electrocardiography data indicated that the fabricated electrodes were demonstrated a performance which is comparable with the commercial electrodes. The results demonstrate that a novel ECG electrodes can be manufactured based on this new composite material and method develop in our laboratory.Master Thesis Development of Nanopatterns on Self Assembled Monolayer (sam) Organic Films Using Scanning Probe Microscope (spm) Nanolithography Techique(Izmir Institute of Technology, 2006) Gül, Semra; Okur, SalihPatterning and fabrication of nanostructures on surfaces is a great demand for nanoscale electronic and mechanical devices. Current techniques such as electron beam lithography and photolithography provides limited resolution and they are not capable of reproducible in nanoscale. Among those, Scanning Probe Microscopy (SPM) lithography that uses a nanometer sharpened tip has demonstrated outstanding capabilities for nanometer level patterning on various surfaces. Moreover, SPM techniques offer creating nanopatterns of Self Assembled Monolayers (SAMs) with molecular precision and visualizing surfaces with the highest spatial resolution. In this work, nanoscratches on gold surfaces and oxidation patterns on titanium surface were successfully performed as example of SPM lithography. In the second stage, Octadecylamine-HCl, Octadecanetiol (ODT) and Decylmercaptan (DM) SAM organic films were fabricated on various substrates; i.e., mica, silica, titanium surface deposited on silicon, n and p type silicon, using self assembly film preparation techniques. The film thicknesses were measured with Atomic Force Microscope (AFM). Nanopatterns were fabricated on SAM films using AFM tip by exerting a local high pressure at the contact that causes the displacement of SAM molecules by a high shear force. It was observed that there was no formation of SAMs on n type Si and silica substrates whereas there were organic assemblies on the other substrates. Fabricated nanopatterns were examined and thickness measurement was done. Molecular lengths of the organics were evaluated by using of SPARTAM 02 LINUX-UNIX with the method of PM3 and the measured values were compared with the calculated ones and it was concluded that monolayers were formed on the surfaces.