Master Degree / Yüksek Lisans Tezleri

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

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Subject: search.filters.subject.Gold nanorods

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Now showing 1 - 3 of 3
  • Master Thesis
    Effect of Gold Nanorod Properties on Lspr Response
    (01. Izmir Institute of Technology, 2023) Bulmuş Zareie, Volga; Tekin, Hüseyin Cumhur; Bulmuş Zareie, Esma Volga; Tekin, Hüseyin Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Optical qualities make gold nanorods (GNRs) excellent for plasmonic biosensors. Localized surface plasmon resonance (LSPR) phenomenon which occurs on GNR surfaces enables the creation of highly sensitive biosensors. The physical properties such as aspect ratio and size are directly related to the LSPR response of GNRs. The aim of this study is to investigate the impact of the aspect ratio (AR) and the interparticle distance on the localized surface plasmon resonance (LSPR) response of GNRs decorated glass sensor chips. For this aim, GNRs were first synthesized using a seed-mediated growth method. The effect of AgNO3 concentration on the AR of GNRs was investigated. It was observed that increasing AgNO3 concentration resulted in GNRs with higher AR and a red shift in the longitudinal plasmon peak wavelength. GNRs with an AR of 4, 6 and 8 were successfully synthesized. Next, the effect of the stabilizer molecule type and molecular weight on the distribution of GNRs on the silanized glass surface was investigated. It was found that the APTES modified glass surfaces cannot be coated with CTAB stabilized GNRs. Using GNRs stabilized with PEG5K resulted in a more homogeneous distribution of GNRs on the glass surface with respect to GNRs stabilized with PEG2K. The interparticle distance between GNRs on the glass surface was successfully controlled by simply concentrating or diluting the GNR solution used for coating the glass surfaces. It was observed that the LSPR peak shifts decreased upon binding of analytes as the interparticle distance between GNRs decreased in the studied range. On the other hand, as the AR decreased, the LSPR response of the GNRs shifted blue. The results presented in this thesis may contribute to future research to improve the potential of LSPR-based biosensors for diverse biomedical and diagnostic applications.
  • Master Thesis
    Design of Localized Surface Plasmon Resonance (lspr) Based Biosensor for Detecting a Potential Cancer Biomarker
    (Izmir Institute of Technology, 2020) Bulmuş Zareie, Volga; Bulmuş Zareie, Esma Volga; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Conventional methods for detection of cancer are invasive, expensive and not suitable for early diagnosis. Therefore, demand for simple, sensitive and rapid biosensors for detection of cancer have been enormous. Gold nanorods (GNRs) have been ideal materials for utilization in biosensors because of their exceptional optical properties. Localized surface plasmon resonance (LSPR) which is created on GNR surface can be used for the development of label-free and sensitive biosensor systems. LSPR responds to changes in the refractive index of the surroundings and this change can be observed as the shift in the maximum absorption wavelengths. In this thesis, an LSPR based GNR biosensor was developed for sensitive detection of a sialic acid as a potential cancer biomarker. For this purpose, GNRs were synthesized at around 40-50 nm in length. Afterwards, glass surfaces were coated with GNRs and functionalized with self-assembling molecules. Specific monoclonal antibodies(Ab) were conjugated to the surface. The surface modifications were characterized via contact angle, scanning electron microscope, Fourier transform infrared spectroscopy and zeta potential. Ab-functionalized glass surfaces were used to quantitatively detect specific molecular bindings via LSPR. The sensitivity of the biosensor was determined as 281 RIU/nm. The detection limit in PBS was 1 nM, while in serum it was found to be as 10 nM because of the high protein content of serum. Control experiments showed that the developed biosensor chip was selective. The proposed system is promising for early diagnosis of cancer since it can detect a potential cancer biomarker at concentrations as low as nanomolar level.
  • Master Thesis
    Development of Mitochondria Targeted Gold Nanorods
    (Izmir Institute of Technology, 2019) Uçak, Hande; Özçelik, Serdar; Özçelik, Serdar; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of Technology
    Lung cancer has the largest number of lives for the global pattern of cancer death. However, the percentage of the cancer treatment is too low. Gold nanoparticles have a widely range in terms of biomedical applications in diagnosis, imaging because of their unique optical properties, simple synthesis techniques, biocompatibility and suitable for easy surface change. Redox reactions in the mitochondria generates a potential called as mitochondria membrane potential. The aim of the study is to design mitochondria targeted gold nanorods and to observe how the designed gold nanorods effects the mitochondria membrane potential by targeting the mitochondria on A549 and BEAS-2B cell lines. Gold nanorods were utilized by seed growth mediated method and the surface bioconjugation was performed with triphenyl phosphonium cation as a mitochondria targeted molecule. Poly (sodium-p-styrene sulfonate) was used to prevent aggregation during the bioconjugation process. Gold nanorods which had 30 nm x 10 nm in length and diameter depending on SEM images had well-defined absorption bands 513 nm and 774 nm in wavelength. Mito-pot analysis with the fluorescent intensity ratio and colocalization analysis with light intensity for targeting gold nanorods to mitochondria showed that the accumulation on mitochondria for TPP-GNR was higher than PSSGNR. TPP-GNR was more toxic than PSS-GNR for both of cell lines by investigations of MTT viability test. TPP-GNR targeted to mitochondria and it affected fundamental cellular functions in mitochondria. To concluded that accumulation on mitochondria was accomplished for TPP-GNR and the decreasing of mitochondria membrane potential was observed on this study.