Kılıç Özdemir, Sevgi
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Kilic, S
Kılıç, Sevgi
Ozdemir, S
Ozdemir, S.
Özdemir, S
Özdemir, S.
Ozdemir, Sevgi Kilic
Özdemir, Sevgi Kılıç
Kilic, S.
Kilic Ozdemir, Sevgi
Kılıç, S.
Kılıç, S
Kilic, Sevgi
Kılıç, Sevgi
Ozdemir, S
Ozdemir, S.
Özdemir, S
Özdemir, S.
Ozdemir, Sevgi Kilic
Özdemir, Sevgi Kılıç
Kilic, S.
Kilic Ozdemir, Sevgi
Kılıç, S.
Kılıç, S
Kilic, Sevgi
Job Title
Email Address
sevgikilic@iyte.edu.tr
Main Affiliation
03.02. Department of Chemical Engineering
Status
Current Staff
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
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WoS Researcher ID
Sustainable Development Goals
1NO POVERTY
0
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2ZERO HUNGER
0
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3GOOD HEALTH AND WELL-BEING
4
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4QUALITY EDUCATION
1
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5GENDER EQUALITY
0
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6CLEAN WATER AND SANITATION
1
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7AFFORDABLE AND CLEAN ENERGY
1
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8DECENT WORK AND ECONOMIC GROWTH
0
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9INDUSTRY, INNOVATION AND INFRASTRUCTURE
4
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10REDUCED INEQUALITIES
0
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11SUSTAINABLE CITIES AND COMMUNITIES
0
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12RESPONSIBLE CONSUMPTION AND PRODUCTION
0
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13CLIMATE ACTION
1
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14LIFE BELOW WATER
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15LIFE ON LAND
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16PEACE, JUSTICE AND STRONG INSTITUTIONS
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17PARTNERSHIPS FOR THE GOALS
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Documents
22
Citations
1055
h-index
13
Documents
14
Citations
294
Scholarly Output
26
Articles
16
Views / Downloads
31044/12056
Supervised MSc Theses
6
Supervised PhD Theses
0
WoS Citation Count
218
Scopus Citation Count
230
Patents
0
Projects
7
WoS Citations per Publication
8.38
Scopus Citations per Publication
8.85
Open Access Source
19
Supervised Theses
6
| Journal | Count |
|---|---|
| Colloids and Surfaces A: Physicochemical and Engineering Aspects | 2 |
| Journal of the Turkish Chemical Society, Section A: Chemistry | 2 |
| Journal of Crystal Growth | 2 |
| American Chemical Society (ACS) Meeting | 2 |
| Energy and Fuels | 1 |
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Scopus Quartile Distribution
Competency Cloud
26 results
Scholarly Output Search Results
Now showing 1 - 10 of 26
Article Citation - WoS: 4Citation - Scopus: 5Quantification of Peg40st Squeeze Out From Dspc/Peg40st Monolayers at Higher Molar Ratios(Elsevier Ltd., 2018) Kılıç, SevgiMixtures of 1,2 Distearoyl-sn-glycero-3-phosphocholine (DSPC) and polyoxyethylene-40-stearate (PEG40St) were prepared at different molar ratios and their miscibility were investigated using Langmuir isotherms. Pure DSPC monolayer exhibited a liquid-condensed (LC) phase whereas PEG40St monolayer exhibited liquid-expanded (LE) phase at the air-water interface at 22 ± 2 °C. At the collapse pressure of 33 mN/m, the PEG40St mean molecular area was calculated to be 28 Å2/molecule for 9:1 composition and 50 Å2/molecule for 5:5 composition, showing an increasing trend with the emulsifier content. A quantification method was developed to estimate the squeeze out amount of PEG40St from Langmuir isotherms of the DSPC/PEG40St mixtures at different molar ratios. Almost 93%, 82%, and 53% of PEG40St displaced for the 9:1, 7:3, and 5:5 mixtures, respectively, at the end of the first collapse plateau and showed a decreasing trend with the PEG40St content. Remaining PEG40St squeezed out at the end of the second collapse plateau, where 20% of PEG40St still contained within the 5:5 composition. It was concluded that increasing PEG40St content would be advantageous to design more stable lipid based microbubbles.Conference Object Investigation of Therapeutic Effects of Doxorubicin Loaded Microbubbles in In-Vivo Breast Cancer Model(Springer, 2017) Serinan, Efe Özgür; Barış, Mustafa; Kürkçü, Gülşah; Önercan, Cansu; Çalışır, Meryem; Altun, Zekiye; Aktaş, Safiye; Aydın, Melek; Kılıç Özdemir, Sevgi; Yılmaz, Osman; Özdemir, Ekrem[No abstract available]Master Thesis Investigation of Shell Microstructure of Microbubbles for Diagnostic Ultrasound(Izmir Institute of Technology, 2013) Köse, Derya; Kılıç Özdemir, Sevgi; Kılıç Özdemir, SevgiIn this study we reported the effect of shear stress, protein adhesion, temperature, secondary interactions and gas core on microbubble stability which are the main reasons of microbubble dissolution in body. Air filled DSPC/PEG40St microbubbles were examined under shear stress. Increasing PEG40St molar ratio increased the resistivity microbubbles against shear stress. To investigate effect of emulsifier type, microbubbles were produced by mixing DSPC with DSPE-PEG1000, DSPE-PEG2000 and PEG40St at 5:5 molar ratio and PEG40St microbubbles were more stable since it provide better curvature to microbubble shell due to its shape. Shear stress experiments were also performed at different temperatures. With increasing temperature microbubbles became less stable since van der Waals interactions between shell components decreased. When microbubbles were filled with perfluorocarbon, since its solubility is lower and more hydrophobic than air, the stability of microbubbles against shear stress increased. Protein adhesion to microbubble shell was investigated by Langmuir Blodgett (LB) and Surface Plasmon Resonance techniques. Both techniques showed that, as the PEG40St molar ratio and packing density increased, protein adhesion decreased. Secondary interactions between shell components were examined via LB technique and visualized via Brewster Angle Microscopy. As third component to DSPC/PEG40St mixture, StGly, StNH2, DSPS, DSTAP was added and ternary mixtures were generally miscible. Since StGly and StNH2 has single tail, they cannot provide curvature in bubble surface. DSPS and DSTAP mixtures may be recommended drug delivery.Article Citation - WoS: 23Citation - Scopus: 31Nano-Caco3 Synthesis by Jet Flow(Elsevier Ltd., 2017) Ülkeryıldız, Eda; Kılıç, Sevgi; Özdemir, EkremA new methodology was introduced to produce hollow nano calcite particles in homogenous size distribution without aggregation. The design consisted of a jet flow system in which the crystallization region was separated from the stabilization region. The newly produced nano CaCO3 particles of about 140 nm were removed from the crystallization region as quickly as possible into the stabilization region before aggregation or crystal growth. In the stages of crystallization, the particles started to dissolve from their edges which opened-up the pores inside the particles. At the late stages of crystallization, the open pores closed. These particles were stable in Ca(OH)2 solution and no aggregation was detected. Different particles with different morphologies can be produced by adjusting the stages in the crystallization.Master Thesis Development of Ultrasound Triggered Drug Delivery Systems for Cancer Treatment(Izmir Institute of Technology, 2019) Önercan, Cansu; Kılıç Özdemir, SevgiDoxorubicin (DOX) is one of the most commonly used hydrophilic anticancer drug in cancer treatment. However, when it is used in free form, it can attack not only cancer cells but also healthy cells. So as to prevent entering of DOX to the healthy cells, the encapsulation method is employed. Liposomes are suitable for encapsulation of DOX but the most important problems with the use of liposome are hand-foot syndrome and stomatitis. Encapsulation method is not enough because of these reasons, thus delivery of DOX to the desired site by targeted therapy has gained interest in recent years. In this study, DOX was encapsulated into liposomes and the DOX loaded liposomes (LipoDOX) was attached to microbubbles (MBs). MBs as ultrasound contrast agents are widely used in medical imaging. Use of MBs in combination of DOX loaded liposomes facilitates the uptake of the drug because ultrasound cavitation results in opening of transient pores in cell membrane via a process named sonoporation. Herein, MB-LipoDOX complex was engineered to optimize the size of the complex as well as the loaded DOX content. For this purpose, determination of incubation temperature and time for DOX loading into liposome and optimization of liposome formulation for maximum DOX loading were studied. Ratios of Lipid/Cholesterol/PEGylated lipid, PEG chain length and PEG molar ratio in liposome were determined. Also, determination of Strept Avidin (StAv) to Biotin ratio in LipoDOX and the amount of LipoDOX in LipoDOX-MB complex were studied. For characterization, Dynamic Light Scattering (DLS) method, Fluorescence Spectrometry method and Coulter Counter device were used. Lipoosme size was found to be associated with the pore size of polycarbonate membrane (200nm) resulting in liposomes at around 190±5 nm in size . When the PEGylated lipid with PEG chain of 2000 was used in liposome structure, particle size distribution is more monodispersed than the others. The maximum amount of DOX loaded liposomes was obtained at 32% Cholesterol, 5% DSPE-PEG2000, after 90 min. incubation at 65oC incubation. Optimum StAv to Biotin ratio in LipoDOX was determined as 1.0. The optimum molar ratio of Biotinylated lipids in LipoDOX was determined as 0.05% and the optimum molar ratio of Biotinylated lipids in MBs was determined as 8%.Article Lipid Monolayer Composition and Production Efficiency in DSPC/PEG40St Microbubbles for Ultrasound Applications(Elsevier, 2025) Kilic, Sevgi; Ozdemir, EkremLipid-coated microbubbles are widely used as ultrasound contrast agents (UCAs) and are being developed as carriers for drug and gene delivery. These microbubbles typically consist of an inert gas core and a stabilizing monolayer shell of phospholipid and a PEGylated emulsifier. In practice, a 9:1 M ratio of DSPC (a saturated phospholipid) to PEG-40-stearate (PEG40St) is conventionally used, under a long-standing assumption that the final composition of the microbubble shell is identical to the initial mixture composition. In this study, we tested that assumption over a wide range of DSPC/PEG40St ratios. Using sonication-based fabrication, we prepared microbubble suspensions with PEG40St fractions from 10 % up to 90 %. We then quantified the shell composition by proton nuclear magnetic resonance (1H NMR) and measured microbubble yield. Contrary to expectation, the PEG40St content in the bubble shells lower than PEG40St added, indicating selective exclusion or "squeezing out" of PEG40St during formation. Only about 4-6 % of the total lipid mixture ended up in the bubble shells and the rest remained as excess in the sub-phase. Thus, 94-96 % of the costly lipid/emulsifier was wasted in the production process. These results overturn the conventional assumption and highlight a critical inefficiency such that substantial amounts of lipid and PEG40St were lost during production, and the bubble yields were low. The findings have important implications for microbubble manufacturing, suggesting that alternative formulations or other production methods are needed to improve efficiency, and thus reduce costs.Article Citation - WoS: 40Citation - Scopus: 46Influence of Tert-Amine Groups on the Solubility of Polymers in Co2(Elsevier Ltd., 2009) Kılıç, Sevgi; Wang, Yang; Johnson, J. Karl; Beckman, Eric J.; Enick, Robert M.There is a need to develop new, non-fluorous polymers that are highly soluble in CO2. Experimental evidence indicates that tertiary amine and pyridine groups may exhibit favorable Lewis acid-Lewis base type interactions with CO2. It is therefore reasonable to assume that incorporation of tertiary amines into the side chain or backbone of non-fluorous polymers may impart a degree of CO2-solubility to the polymer. We present experimental results for eight different tert-amine-containing polymers. Of these polymers, only propyl dimethylamine-functionalized poly(dimethylsiloxane) is soluble in CO2 at temperatures and pressures accessible in our experiments, but even this polymer is less soluble than non-functionalized poly(dimethylsiloxane) at the same chain length. We have performed ab initio calculations on tertiary amine-containing moieties representative of some of the polymers examined experimentally. Our calculations confirm that amine-CO2 interactions are indeed energetically favorable. However, we also find that the moiety self-interactions are typically more favorable than the CO2-moiety interactions. This indicates that the lack of solubility of amine-containing polymers in CO2 is a direct result of strong polymer-polymer interactions.Master Thesis Design and Characterization of Shell Structure of Microbubbles Used in Ultrasound Imaging(Izmir Institute of Technology, 2012) Bölükçü, Elif Şeniz; Kılıç Özdemir, SevgiThe main goal of the study is to redesign the microbubble (MB) shell structure and investigate the interactions between the shell components in the mixed monolayers treated as a model for MBs’ shell in order to improve the stability. To examine effects of emulsifier type (DSPC/PEG40 St, DSPC/DSPE-PEGn) and additional components (DSPC/PEG40 St/DSPG, DSPC/PEG40 St/DSPA, DSPC/PEG40 St/DSPE) on stability, molecular interactions and morphological properties, mixtures having various compositions were investigated by Langmuir Blodgett (LB) method and Atomic Force Microscope (AFM) and Brewster Angle Microscope (BAM). For DSPC/PEG40 St monolayers thermodynamically analysis indicated that the attractive forces between the components in the monolayer of 30% PEG40 St were very strong. It was observed that addition of large amount of peg-grafted phospholipids (lipopolymer) increased the attractive forces between molecules in DSPC/DSPE-PEG1000 and DSPC/DSPE-PEG350 monolayers unlike DSPC/DSPE-PEG2000 monolayers. Additionally, the use of different phospholipid as an additional component such as DSPG, DSPE and DSPA in DSPC/PEG40 St mixture signified that intermolecular forces were influenced by the monolayers’ compositions and polar headgroups differences. It was noticed that among the ternary mixtures consisting 70% DSPC, DSPC/PEG40 St/DSPE monolayers exhibited stronger molecular interaction than DSPC/PEG40 St/DSPG and DSPC/PEG40 St/DSPA monolayers while DSPC/PEG40 St/DSPA mixtures showed stronger interaction for mixtures composed of 50% PEG40 St. However, phase separations detected at some regions for these monolayers by BAM and AFM may affect the stability negatively. Therefore, thermodynamically analysis, BAM and AFM results should be evaluated together to assess potential MBs’ shell structures.Article Citation - WoS: 20Citation - Scopus: 23Rice-Like Hollow Nano-Caco3 Synthesis(Elsevier Ltd., 2016) Ülkeryıldız, Eda; Kılıç, Sevgi; Özdemir, EkremWe have shown that Ca(OH)2 solution is a natural stabilizer for CaCO3 particles. We designed a CO2 bubbling crystallization reactor to produce nano-CaCO3 particles in homogenous size distribution without aggregation. In the experimental set-up, the crystallization region was separated from the stabilization region. The produced nanoparticles were removed from the crystallization region into the stabilization region before aggregation or crystal growth. It was shown that rice-like hollow nano-CaCO3 particles in about 250 nm in size were produced with almost monodispersed size distribution. The particles started to dissolve through their edges as CO2 bubbles were injected, which opened-up the pores inside the particles. At the late stages of crystallization, the open pores were closed as a result of dissolution-recrystallization of the newly synthesized CaCO3 particles. These particles were stable in Ca(OH)2 solution and no aggregation was detected. The present methodology can be used in drug encapsulation into inorganic CaCO3 particles for cancer treatment with some modifications.Article Effect of Temperature on Stability of Lipid Microbubbles(Turkish Chemical Society, 2019) Kılıç, SevgiThe effect of temperature on stability of lipid microbubble shell containing polyethyleneoxide-40-stearate (PEG40St) as emulsifier was investigated. Microbubbles at 4 °C were subjected to different temperatures up to 48 ºC (down-to-up) and it was found that both the number and the size of microbubbles remained unchanged in the population up to a certain time, so called “onset time”. The onset time was about 6 hours at 10 °C, 2 hours at 20 °C and shorter at elevated temperatures, exhibiting an exponential decrease with increasing temperature. Once the onset time was reached, the number of microbubbles started to decrease and the average size of the population started to increase. Observation of single microbubbles on a constant temperature heating stage exhibited that each microbubble had its own onset time, with the smaller microbubbles vanishing earlier than the larger ones. The Langmuir monolayer studies showed that hydration degree of the emulsifier PEG chains decreased with temperature, causing them go through conformational changes and subsequently destabilization of the shell. By subjecting the freshly produced microbubbles directly to the desired temperatures in up-to-down fashion, more stable microbubbles were able to be produced, with their onset time increased 40% at 10 °C to 500% at 38 °C. Overall, the results suggest that the new strategies need to be developed to control the collapse process in the microbubble shell resulting from the conformational changes in the PEG chains of the emulsifier for the design of more stable microbubbles. © 2019, Turkish Chemical Society. All rights reserved.
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