Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Serum albumin

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  • Master Thesis
    Determination of Cadmium Bound To Whey Proteins by Laser-Induced Breakdown Spectroscopy at Low Pressures
    (2023) Yalçın, Şerife; Yaman, İlayda; Yalçın, Şerife Hanım; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    In this thesis study, a dried-droplet LIBS methodology at reduced pressures for determining cadmium in aqueous media and in biological samples has been developed. With the advantage of the signal enhancement effect at reduced pressures, the optimum pressure for Cd detection was determined. Results were justified with the plasma images taken at different pressures. 100 mbar pressure was found as the optimum for most emission lines of Cd. To find the most suitable substrate onto which analyte droplets will be loaded, silicon wafer-based substrates of different coating types and coating thicknesses were studied. Among them, the c-Si substrate was found to show the highest signal enhancement for Cd detection. The performance of the methodology for quantitative analysis of Cd was shown by standard solutions and certified reference water samples. Calibration curves were constructed, and performance characteristics (limit of detection, accuracy, precision) were evaluated. Detection limits in absolute amounts of 6.8 pg and 1.05 pg were obtained at atmospheric and 100 mbar pressures, respectively. The application studies involve the determination of Cd bound to whey proteins. For this purpose, standard protein (BSA) and whey protein extracted from the milk were incubated in standard Cd solutions for several hours and filtered through cut-off filters via centrifugation. The unreacted cadmium in the filtrate and Cd-bound protein in fraction were analyzed separately. It has been shown that dried-droplet LIBS at reduced pressures is a suitable methodology for identifying and determining Cd and Cd bound to proteins with a picogram amount of detection capability.
  • Master Thesis
    Synthesis of Drug Loaded Ph Sensitive Albumin Nanoparticles
    (2023) Adem, Umut; Akdoğan, Yaşar; Akdoğan, Yaşar; Adem, Umut; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Serum albumin-based nanoparticles (NPs) are commonly used for drug delivery due to their stability, biodegradability, ease of particle size control and no toxicity. In this study, bovine serum albumin (BSA) was functionalized with catechol-containing dopamine (D) to synthesize D-BSA NPs using pH responsive catechol-metal coordination bonds. Instead of using glutaraldehyde, V(III) ion was used as a cross-linker for synthesizing NPs. Catechol-V(III) coordination bonds provided pH responsive NPs due to their different stoichiometry of catechol-metal complexes (e.g. mono-, bis- or tris-) at different pH values. For the synthesis of D-BSA NPs, desolvation method was used with acetone as desolvating agent. Uniformly sized NPs were synthesized with an average of 294 nm with a PDI value of 0.15. Doxorubicin is loaded to NPs with a 15:1 DOX:D-BSA molar ratio. DOX encapsulation efficiency and drug loading capacity of D-BSA NPs were found to be 98% and 10%, respectively. Conversion to bis- and/or mono- catechol-V(III) complexes in acidic medium resulted in degradation of NPs and rapid release of the loaded doxorubicin (DOX). DOX releases reached to 51, 76 and 95% at pH values 7.4, 5.5 and 4.2, respectively at the end of 80 hours. Furthermore, the cytotoxic effects of prepared D-BSA NPs, in comparison to free DOX were studied with MCF-7 cells. Increasing D-BSA concentrations up to 0.2 mg/mL did not affect the cell viability, significantly. But, upon cell (MCF-7) uptake in vitro, DOX-loaded D-BSA NPs and free DOX reduced cell viability by 75% and 20% in 24 hours, respectively.
  • Master Thesis
    Preparation and Characterization of Drug Loaded Cationic Albumin Nanoparticles
    (01. Izmir Institute of Technology, 2021) Akdoğan, Yaşar; Emrullahoğlu, Mustafa; Sözer, Sümeyra Çiğdem; Akdoğan, Yaşar; Emrullahoğlu, Mustafa; 03.09. Department of Materials Science and Engineering; 04.04. Department of Photonics; 01. Izmir Institute of Technology; 03. Faculty of Engineering; 04. Faculty of Science
    Serum albumin protein behaves as a carrier and transporter for both hydrophilic and hydrophobic drugs. Therefore, albumin could be used in the drug carrier systems. Since albumin nanoparticles have a negative charge under physiological conditions, their anionic drug loading and delivering capacities are restricted. This study aims to obtain higher anionic drug loading capacity by producing cationic bovine serum albumin nanoparticles (cBSA NPs). Firstly, the carboxyl groups of amino acids present on the surface of albumin were conjugated with ethylenediamine to change the charge of albumin from negative to positive. Then, cBSA NPs were obtained using the desolvation process. Anionic salicylic acid (SA) was used for drug loading studies of the obtained cBSA NPs. SA loading and releasing experiments were studied with UV-Vis and electron paramagnetic resonance (EPR) spectroscopy. In the UV-Vis, the drug loading capacity of cBSA NPs was found to increase ~2 fold, and drug release was slower compared to BSA NPs. For EPR studies, SA was labeled with stable radicals. Spin labels allow the simultaneous monitoring of bound and free drugs in the same sample. The drug was loaded into nanoparticles using two methods. Based on EPR results, it was found that drug was loaded to cBSA NPs with 50% and 93%, and to BSA NPs with 4% and 15% ratios, by desolvation and incubation, respectively. Thus, UV-vis and EPR measurements showed that cBSA NPs have higher SA loading potential and slower release ability compared to anionic albumin nanoparticles.
  • Master Thesis
    Preparation and Characterization of Serum Albumin Nanoparticles Obtained From Modified Bovine Serum Albumin
    (01. Izmir Institute of Technology, 2021) Akdoğan, Yaşar; Demir, Mustafa Muammer; Akdoğan, Yaşar; Demir, Mustafa Muammer; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The serum albumin has been used as a drug nanocarrier for a long time due to its rich drug transportation ability. Here, modified bovine serum albumin (BSA) proteins were obtained by conjugation with ethylenediamine and dopamine molecules, separately. Using these modified proteins, new BSA nanoparticles were obtained by a desolvation method. Native BSA has a net negative charge at the physiological condition. However, ethylenediamine conjugation yields a positive charge on it, and thus produces cationic BSA (cBSA) protein. On the other hand, dopamine functionalization (D-BSA) makes BSA eager to coordinate with transition metals. After preparation of modified proteins (cBSA and D-BSA), their nanoparticles were prepared with desolvation method but using different crosslinking mechanisms. For cBSA NPs preparation, a traditional crosslinking agent of glutaraldehyde was used. However, for D-BSA NPs preparation, Fe(III) ions were added to the system to achieve the stable nanoparticle formation. In order to obtain cBSA NPs, several organic solvents were used as desolvating agents. cBSA NPs with an average size around 200 nm were obtained in a high formation yield (54.8%) only through addition of acetonitrile to the cBSA aqueous solution. Similarly, different desolvating agents were studied to obtain D-BSA NPs. The promising results were obtained upon addition of 1:5 (v/v) of water/acetone mixture. After addition of the desolvating agent, Fe(III) ions were added to the solution to interconnect D-BSA with each other. This connection is pH sensitive therefore albumin nanoparticles were stable at basic pH values but not at acidic pH values. By this way, pH sensitive D-BSA NPs around 300 nm particle sizes were obtained.