Master Degree / Yüksek Lisans Tezleri

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Department: search.filters.department.Thesis (Master)--İzmir Institute of Technology, BioengineeringSubject: search.filters.subject.Gold nanoparticles

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  • Master Thesis
    Green Synthesis of Metal Nanoparticles and Their Applications as Plasmonic Substrates
    (Izmir Institute of Technology, 2018) Elveren, Beste; Arslan Yıldız, Ahu; Yıldız, Ümit Hakan; Arslan Yıldız, Ahu; Yıldız, Ümit Hakan; 04.01. Department of Chemistry; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    Gold nanoparticles (GNPs) have been widely used in diagnostic, tissue engineering, and drug delivery fields, in the last decades. Generally, reducing gold salts to zero valent gold has been accomplished by harsh chemicals and strong reducing agents, which cause toxicity and eventually limiting the bioapplications. Green synthesis is a newly developing methodology to synthesize GNPs. Especially natural products and plants extracts are commonly preferred for green synthesis based on their natural content. Biological molecule-capped GNPs, are more biofriendly and biocompatible nano-materials that can be used for varied applications.1-3 Sensor applications; varying from biosensing to environmental analysis, are an important field that GNPs were intensively utilized.4-5 Cyanide ion (CN-) has been considered as one of the main pollutants of water, because of its rapid discharge. CN- is currently being used in industry such as; polymer synthesis6, noble metal mining7, pest control8, plastics production etc., at large scale. However, there is an unmet need for CN- detection and monitoring. Colorimetric detection of CN- that utilizes GNPs has been done by several researchers.9-10 However, in all these studies reduction of GNPs were done by strong reducing agents. Green synthesis of GNPs eliminates the toxic side-products that can be harmful to both environment and human health. To overcome this problem green synthesized GNPs were used to establish the sensor platform, which can be further employed for CN- detection. Oxidation of GNPs in the presence of cyanide molecules is a direct-forward, colorimetric and optical method that requires no toxic chemicals; therefore it is a greener approach towards CN- detection in water resources.
  • Master Thesis
    Development of Gold Nanoparticle-Based Plasmonic Assay Platform for Esherichia Coli Detection
    (Izmir Institute of Technology, 2017) Erdoğan, Duygu; Yıldız, Ümit Hakan; Arslan Yıldız, Ahu; Yıldız, Ümit Hakan; Arslan Yıldız, Ahu; 04.01. Department of Chemistry; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    The traditional methods for pathogen detection have long detection time and insufficient sensitivity. Optical methods can overcome these drawbacks. There are solution based nanoparticle growth in the literature to enhance a surface sensitivity for biosensing applications. In this project, surface refractive index (RI) sensitivity was enhanced on solid support via gold growth to develop a label free, simple and costeffective methodology for bacteria screening. The gold nanoparticles (GNPs) were grown on solid support by using 20 μl of HAuCl4 / 80 μl of NH2OH at varied incubation times. Firstly, about 20 nm GNPs were synthesized and immobilized on polystyrene surfaces. Then, these GNPs were utilized as seed particles, and grown on solid support. During GNPs growth, a red shift in the plasmonic wavelength was observed. Morphological characterization showed that almost uniform gold growth could be achieved. The plasmonic platform sensitivity was validated by varied concentrations of sucrose, ethanol and BSA solutions, showing that the plasmonic platform gave a response to any small RI change. Next, two different E.coli bacterial strains’ adsorption was tested. Adsorption screenings for about 107 E.coli DH5-alpha cells/ml and 107 E.coli BL21(DE3) cells/ml in Phosphate Buffer Saline were made on growth gold surfaces. Further, E.coli BL21(DE3) containing milk and apple juice were also adsorbed on these gold surfaces with a 30 min incubation time. The results showed that these gold surfaces exhibit higher binding kinetics for bacteria. Therefore, the proposed LSPR-based label free methodology can be an alternative to the bacteria screening in water or food samples.