Özçelik, Serdar
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Ozcelik, Serdar
Özçelik, S
Özçelik, S.
Ozcelik, S
Ozcelik, S.
Özçelik, S
Özçelik, S.
Ozcelik, S
Ozcelik, S.
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Email Address
serdarozcelik@iyte.edu.tr
Main Affiliation
04.01. Department of Chemistry
Status
Current Staff
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WoS Researcher ID
Sustainable Development Goals
1NO POVERTY
0
Research Products
2ZERO HUNGER
0
Research Products
3GOOD HEALTH AND WELL-BEING
5
Research Products
4QUALITY EDUCATION
1
Research Products
5GENDER EQUALITY
0
Research Products
6CLEAN WATER AND SANITATION
1
Research Products
7AFFORDABLE AND CLEAN ENERGY
5
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8DECENT WORK AND ECONOMIC GROWTH
1
Research Products
9INDUSTRY, INNOVATION AND INFRASTRUCTURE
16
Research Products
10REDUCED INEQUALITIES
0
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11SUSTAINABLE CITIES AND COMMUNITIES
0
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12RESPONSIBLE CONSUMPTION AND PRODUCTION
1
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13CLIMATE ACTION
5
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14LIFE BELOW WATER
0
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15LIFE ON LAND
0
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16PEACE, JUSTICE AND STRONG INSTITUTIONS
0
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17PARTNERSHIPS FOR THE GOALS
0
Research Products
Documents
54
Citations
1084
h-index
18
Documents
53
Citations
1040
Scholarly Output
67
Articles
43
Views / Downloads
212435/27144
Supervised MSc Theses
14
Supervised PhD Theses
6
WoS Citation Count
642
Scopus Citation Count
550
Patents
0
Projects
11
WoS Citations per Publication
9.58
Scopus Citations per Publication
8.21
Open Access Source
56
Supervised Theses
20
| Journal | Count |
|---|---|
| Journal of Physical Chemistry C | 5 |
| Nanotechnology | 5 |
| Journal of Physical Chemistry B | 4 |
| Journal of Luminescence | 4 |
| Journal of Fluorescence | 2 |
Current Page: 1 / 6
Scopus Quartile Distribution
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67 results
Scholarly Output Search Results
Now showing 1 - 10 of 67
Article Citation - WoS: 22Citation - Scopus: 18Nuclear-Targeted Gold Nanoparticles Enhance Cancer Cell Radiosensitization(IOP Publishing, 2020) Pratx, Guillem; Özçelik, SerdarRadiation therapy aims to kill or inhibit proliferation of cancer cells while sparing normal cells. To enhance radiosensitization, we developed 40 nm-sized gold nanoparticles targeting the nucleus. We exploited a strategy that combined RGD and NLS peptides respectively targeting cancer cell and the nucleus to initiate cell-death activated by x-ray irradiation. We observed that the modified gold nanoparticles were either translocated in the nuclei or accumulated in the vicinity of the nuclei. We demonstrated that x-ray irradiation at 225 kVp energy reduced cell proliferation by 3.8-fold when the nuclear targeted gold nanoparticles were used. We determined that the radiation dose to have a 10% survival fraction was reduced from 11.0 Gy to 7.1 Gy when 10.0 mu g ml(-1)of the NLS/RGD/PEG-AuNP was incubated with A549 cancer cells. We conclude that the peptide-modified gold nanoparticles targeting the nucleus significantly enhance radiosensitization.Article Citation - WoS: 7Citation - Scopus: 10Enhanced Light–matter Interaction in a Hybrid Photonic–plasmonic Cavity(Springer, 2021) Gökbulut, Belkıs; İnanç, Arda; Topçu, Gökhan; Özçelik, Serdar; Demir, Mustafa Muammer; İnci, Mehmet NaciStrongly concentrated optical fields around a metal nanoparticle in the close vicinity of a dipole noticeably facilitate dramatic changes in the localized density of states due to hybrid photonic–plasmonic mode couplings as compared to that of the pure cavity mode fields. Significant variations of the field intensity in the presence of the metal nanoparticle elucidate enhanced light–matter interaction in a hybrid structure. The enhancement factor of the light–matter interaction is studied through the single-atom cooperativity parameter, which is directly proportional to the ratio of the fluorescence lifetimes of the off-resonant and on-resonant emission. A compact and cost-effective hybrid device, which includes a microfiber cavity, supporting whispering gallery modes, and a well-defined solid nanostructure, consisting of a gold nanoparticle core, overcoated by a silica shell, and decorated with CdS/CdSe quantum dots, is demonstrated to offer an outstanding potential for the enhancement of light–matter interaction. Surface plasmons of a gold nanoparticle, placed inside a hollow cylindrical nanostructure at the surface of a microfiber, are activated upon excitation of the dipoles of the quantum emitters, which are on-resonance with the whispering gallery mode. Time-resolved experiments demonstrate that the single-atom cooperativity parameter of the quantum dots is enhanced by a factor of about 4.8 in the presence of the gold nanoparticle being simultaneously in strong interaction with the cavity mode field and the metal nanoparticle’s surface plasmons.Article Citation - WoS: 100Cholesterol Dictates the Freedom of Egf Receptors and Her2 in the Plane of the Membrane(Elsevier Ltd., 2013) Orr, Galya; Hu, Dehong; Özçelik, Serdar; Wiley, H. Steven; Colson, Steven D.; Opresko, Lee K.The flow of information through the epidermal growth factor receptor (EGFR) is shaped by molecular interactions in the plasma membrane. The EGFR is associated with lipid rafts, but their role in modulating receptor mobility and subsequent interactions is unclear. To investigate the role of nanoscale rafts in EGFR dynamics, we used single-molecule fluorescence imaging to track individual receptors and their dimerization partner, human epidermal growth factor receptor 2 (HER2), in the membrane of human mammary epithelial cells. We found that the motion of both receptors was interrupted by dwellings within nanodomains. EGFR was significantly less mobile than HER2. This difference was likely due to F-actin because its depolymerization led to similar diffusion patterns between the EGFR and HER2. Manipulations of membrane cholesterol content dramatically altered the diffusion pattern of both receptors. Cholesterol depletion led to almost complete confinement of the receptors, whereas cholesterol enrichment extended the boundaries of the restricted areas. Interestingly, F-actin depolymerization partially restored receptor mobility in cholesterol-depleted membranes. Our observations suggest that membrane cholesterol provides a dynamic environment that facilitates the free motion of EGFR and HER2, possibly by modulating the dynamic state of F-actin. The association of the receptors with lipid rafts could therefore promote their rapid interactions only upon ligand stimulation.Master Thesis Development of Sub-Cellular Organelle Targeted Fluorescent Silica Nanoparticles(Izmir Institute of Technology, 2019) Yüksel, Almila; Özçelik, Serdar; Özçelik, SerdarSilica nanoparticles have been studied extensively in cellular applications due to their physicochemical properties. The surface of silica nanoparticles represent the key parameter in biological studies. Owing to their versatile surface chemistry, have ability to increase bioavailability and selectivity. Therefore, it is significant to understand how biomolecules interact with the surface of silica nanoparticles. The study reviews how synthesized both negative and positive potential silica nanoparticles and can transfer their properties to the cells. In the second part, our synthesized silica nanoparticles were characterized physicochemically using some instrumental devices. To answer the role of silica nanoparticles in the cells, some outcomes such as viability test, image analysis, colocalization analysis and mitochondrial membrane potential were investigated. A549 (adenocarcinomic human alveolar basal epithelial cells) and BEAS-2B (human bronchial epithelial cells) cell lines were selected in our studies. Our results showed the cytotoxicity was dose and time dependent in direct proportion. Mitochondrial accumulation were observed in cells treated with the silica nanoparticles according to Pearson’s Coefficient Correlation and Image J analysis. The study concluded that the silica nanoparticles can be used in the field of targeted delivery and bioimaging in cellular studies.Article Citation - WoS: 4Citation - Scopus: 6Absorption Spectrum of Monomeric Pseudoisocyanine: a New Perspective and Its Implications for Formation and Spectral Response of J-Aggregates in Solution and in Thin Films(Elsevier Ltd., 2008) Gülen, Demet; Özçelik, SerdarWe argued against the current spectral assignment for absorption spectrum of monomeric PIC which is widely accepted since the pioneering works of Scheibe and Jelley [G. Scheibe, Angew. Chem. 49 (1936) 563; E.E. Jelly, Nature 138 (1936) 1009]. A new spectrum is presented along with its conceptual basis. The hypothesized spectrum attributes the previous 0-0 (≈525 nm) and 0-1 (≈490 nm) assignments, respectively, to intermediates acting as the precursor of J-aggregates and to the 0-0 transition of monomeric PIC and brings the spectrum in accord with the seemingly universal spectral fingerprint of cyanines. The hypothesis is used to analyze and interpret the temperature dependence of the UV-vis absorption of PIC aggregates in saline aqueous solution by incorporating the J-band simulations within frenkel exciton formalism. Its implications for aggregate formation kinetics are given on the basis of current spectroscopic evidence. The hypothesis readily answers several long-standing questions: Why compared to many other cyanines at least an order of magnitude higher dye concentration is needed to form J-aggregates of PIC? Why are there no precursors, since aggregation is expected to be a consecutive process? A large number of observations on steady-state and time-resolved spectral properties, and aggregation kinetics in solution/thin films are likely to find reasonable explanations within this hypothesis.Master Thesis Rendering Optical and Structural Properties of Semiconductor Nanocrystals by Chemical Doping(Izmir Institute of Technology, 2012) Sevim, Seçil; Özçelik, Serdar; Özçelik, SerdarSemiconductor nanocrystals are widely used in technologic applications because of their unusual and tunable optical properties. In this study we synthesized two type of semiconductor nanocrystals by the aqueous synthesis method. Colloidal HgCdTe semiconductor nanocrystals were synthesized by cation exchange reaction at room temperature. The absorption and photoluminescence spectra of water dispersible semiconductor nanocrystals appeared in NIR range of the electromagnetic spectrum. Aging process showed higher shift to red region in absorption and fluorescence spectra for HgCdTe nanocrystals. Increasing the initial Hg:Cd mole ratio spectral tuning was achieved. The size of the semiconductor nanocrystals was controlled between 8 nm to 44 nm by selecting the size of initial CdTe nanocrystals. Water dispersible Gd doped CdTe nanocrystals were also studied by changing initial Cd:Gd mole ratio. CdS shell was formed in order to make more compact and stable Gd doped CdTe nanocrystals. Size of Gd doped CdTe/CdS nanocrystals was tuned up to 38 nm by increasing initial Gd content. The optical spectra of Gd doped CdTe nanocrystals were in the range from 535 nm to 555 nm after 4 hours reaction time. Photoluminescence quantum efficiencies of Gd doped CdTe nanocrystals were measured and found out that doping Gd, decrease the quantum yield of nanocrystals. We concluded that CdTe nanocrystals can be used to synthesize doped nanocrystals by chemical doping. We demonstrated that optical and structural properties of Hg and Gd doped CdTe can be rendered by chemical doping.Master Thesis Synthesis and Characterization of Monodispere Silica Based Functional Nanoparticles for Multi-Purpose Applications(Izmir Institute of Technology, 2009) Altın, Burcu; Özçelik, SerdarThe Stöber method was performed to tune the size of monodisperse silica nanoparticles in the range of 10 to 500 nm. It was observed that increasing amount of reactants favors the formation of larger particles A Stöber method in the presence of L-lysine as a catalyst instead of ammonia was developed to prepare well-ordered, highly monodisperse silica nanoparticles based on the hydrolysis and condensation of TEOS. The effect of medium temperature, amounts of L-lysine, TEOS, octane and dye on the size of particle was investigated. It was found that L-arginine increased the size of particles. The amount of TEOS was determined to be 50.0 mmol to obtain the smallest size of particle. The mole of L-lysine slightly altered the size of particles, however the surface of particles was substantially covered by L-lysine. The presence of octane does not change the size of particles. The amount of dye molecule Rhodamine B isothiocyanate (RBITC) does not alter the size of nanoparticles. We showed that temperature plays important role tuning the particle size from 5.0 nm to 80.0 nm.MTT assay indicates no cytotoxicity of the silica particles against MCF-7 (human breast cancer cell lines) and PC-3 (human prostate cancer cell lines) cancer cell lines. The particles enter to the cells within 5 minutes with a concentration of 0.1.g/mL. We propose that these particles can be used in the field of bioimaging and drug delivery.Article Citation - WoS: 19Citation - Scopus: 19Systematic Tuning the Hydrodynamic Diameter of Uniformed Fluorescent Silica Nanoparticles(American Chemical Society, 2011) Durgun, Gülay; Ocakoğlu, Kasım; Özçelik, SerdarWe report a facile method for systematic tuning the hydrodynamic diameter of uniformed fluorescent silica particles in the size range from 12 to 465 nm. Dynamic light scattering and electron microscopy studies demonstrate that the hydrodynamic size distribution of the silica particles is uniform. We show that the initial amounts of ethanol and ammonia are essential to tune the size of these particles. The hydrodynamic diameter of such a particle increases as the amount of ammonia is increased. On the other hand, an increase in the amount of ethanol leads to the formation of smaller particles. Higher initial amount of ethanol yield an increase in the concentration of ethoxide ions and a decrease in the concentration of hydroxide ions. Such control over the concentration of hydroxide ion, which is responsible for the formation of siloxane bonds, causes a controlled-growth of the silica particles, resulting in precise tuning the hydrodynamic size. We confirm that a linear relationship exists between size and brightness of particles, demonstrating that the amount of dye molecules in such particles can be regulated by the presented method. We prove that the silica network provides protection for dye molecules encapsulated in particles against solvents, fluorescence quenchers, and unfavorable pH of environments. Moreover, the fluorescent silica particles with the size of 12, 50 and 250 nm were found to not be cytotoxic against the epithelial cell lines of MCF7 and PC3 even when the dosage levels up to 1.0 mg/ml and incubation periods up to 72 hours were applied.Article Citation - WoS: 11Citation - Scopus: 11Investigation of Structure-Spectroscopy Relationship of Twodimensional J-Aggregates of Tetrachlorobenzimidazolorcarbocyanine Preferentially Oriented in Poly-Vinly Thin Films(Elsevier Ltd., 2009) Gülen, Demet; Atasoylu, Onur; Özçelik, SerdarThe structure–spectroscopy–function relationship of 1,1 0 ,3,3 0 -tetraethyl-5,5 0 ,6,6 0 -tetrachlorobenzimidazolocarbocyanine (TTBC) aggregates is studied using a combination of experimental and theoretical techniques. The aggregates are macroscopically aligned in poly-vinyl-alcohol thin films by vertical spin coating. Angular dependence of the UV–Vis spectra is measured at eleven different orientations between the electric field polarization and the macroscopic alignment axis. The aggregates are characterized by a pair of Davydov split bands with opposite polarization behaviors: an H-band (505 nm) and a J-band (594 nm) polarized respectively, close to being parallel and perpendicular to the alignment axis. Spectral response is interpreted via simulations within the Frenkel exciton formalism. TTBC aggregates are shown to assume very similar internal molecular packing (herringbone) and dynamics of excited states (phononassisted intraband and interband relaxations) in ionic aqueous solution and in thin films. The general conclusions on the structure–spectroscopy–function relationship are expected to hold for other cyanine aggregates with the same generic spectral features.Article Citation - WoS: 3Citation - Scopus: 6Hybrid Photonic-Plasmonic Mode-Coupling Induced Enhancement of the Spontaneous Emission Rate of Cds/Cdse Quantum Emitters(Elsevier, 2022) Gökbulut, Belkıs; İnanç, Arda; Topçu, Gökhan; Özçelik, Serdar; Demir, Mustafa Muammern this paper, a hybrid photonic-plasmonic resonator, which comprises an electrospun polymer fiber with a micrometer diameter and a core/shell nanostructure with a gold nanoparticle core, is constructed to investigate the dynamics of the coupled spontaneous emission of CdS/CdSe quantum dots (QDs). The gold nanoparticle core; covered with a silica shell, anchored with individual CdS/CdSe QDs, is placed inside a hollow cylindrical nanocavity formed on the surface of the microfiber to enable integration of the optical mode with the plasmonic effect, which is induced by the localized surface plasmons of the metal nanoparticle being present in the vicinity of the dipoles. The spontaneous emission rate of the QDs, coupled into the hybrid photonic-plasmonic mode, is measured to enhance by a factor of 23 via a time-resolved experimental technique. This result suggests that the regeneration of the optical mode-field inside the photonic-plasmonic resonator through the interaction of the dipoles with the localized surface plasmons of a metal nanoparticle strongly enhances the density of the electromagnetic states of the quantum emitters to facilitate an enhanced spontaneous emission within the host medium of the proposed polymer based-photonic structure.