Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Influence of Soil Characteristics on the Phytochemistry of Evergreen Ivy (Hedera Helix L.) Leaves in Deciduous Forests(Wiley-v C H verlag Gmbh, 2025) Yildirim, Elif Begum; Özdemir, Durmuş; Ozer, Gulcin; Sen, Nisa Beril; Ozdemir, Emrah; Makineci, Ender; Ozdemir, Durmus; Guzelmeric, Etil; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyThe evergreen ivy (Hedera helix L.), traditionally used to treat respiratory conditions, contains triterpene saponins, primarily hederacoside C, and various phenolic compounds. This study investigated the relationships between the chemical composition of ivy leaves and their natural growing conditions (moisture, temperature, pH, and electrical conductivity of soil). Ivy leaves were collected monthly over 1 year from oak and beech forests. Hederacoside C, rutin, chlorogenic acid (ChA), neoChA, 4,5-dicaffeoylquinic acid (DCQA), and 3,5-DCQA were analyzed by high-performance thin-layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). Soil parameter data, along with the quantitative HPLC results of ivy leaves, were first subjected to bivariate analysis, which revealed significant correlations, particularly between soil moisture, soil temperature, and the chemical composition of ivy leaves. In addition, ivy samples were classified and clustered based on seasons by principal component analysis (PCA) and hierarchical cluster analysis (HCA), regardless of their collection sites. Digitized HPTLC chromatograms were evaluated by PCA and partial least squares discriminant analysis (PLS-DA) analyses; PCA enabled the grouping of ivy leaves based on their collection sites, and PLS-DA categorized the samples by seasons. The evaluation of the relationships between the phytochemistry of ivy leaves and their natural growing conditions has been reported for the first time.Article The Effect of Co-Delivery of Oxygen and Antibacterial Drug Gentamicin From Alginate-Based Nanocomposite Hydrogels on Bacterial Apoptosis and Cell Viability(Wiley-v C H verlag Gmbh, 2025) Tepeli, Dilek; Kehr, Nermin Seda; Tepeli, Dilek; Demirci, Eylem Kurulgan; Pehlivanoglu, Pelin; Kehr, Nermin Seda; 04.01. Department of Chemistry; 01. Izmir Institute of Technology; 04. Faculty of ScienceThere is a need to develop multifunctional biomaterials that can deliver oxygen and antibacterial drugs together for effective wound healing applications. Here, we report a novel biomaterial capable of co-delivering O2 and the antibacterial drug Gentamicin (GEN) for a period of 7 and 15 days, respectively. This biomaterial is fabricated by the synthesis of perfluorocarbon-based periodic mesoporous organosilica (PMOF) and the loading of its pores with GEN (GENPMOF). The synthesized GENPMOF is incorporated in alginate hydrogel to obtain Alg-GENPMOF with O2 and GEN co-delivery ability. Our results show that PMOF and GENPMOF have concentration-dependent toxicity on both Gram-negative E. coli and Gram-positive S. aureus bacteria. The most effective concentration of PMOF and GENPMOF (0.5 mg/mL) show little toxic effect for fibroblast cells. On the other hand, Alg-PMOF and Alg-GENPMOF prepared using this concentration require a long incubation time with E. coli to induce apoptosis. However, an incubation period of 1 day is sufficient to inhibit the growth of S. Aureus. Furthermore, Alg-PMOF and Alg-GENPMOF increase fibroblast cell viability under both normoxic and hypoxic conditions while slightly decreasing cancerous Malme-3M cell viability within 5 days of incubation.Article Citation - WoS: 2Citation - Scopus: 2Hybrid Preceramic Aerogels for Oil and Solvent Cleanup(Wiley-v C H verlag Gmbh, 2025) Icin, Oyku; Ahmetoğlu, Çekdar Vakıf; Vakifahmetoglu, Cekdar; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study presents the first synthesis and characterization of monolithic hybrid preceramic aerogels using distinct drying techniques: ambient pressure (ambigels) and CO2 supercritical drying. Polymeric ambi/aerogels, derived from polyhydromethlysiloxane (PHMS) and divinylbenzene (DVB), are processed at 200 degrees C, while hybrid ceramic-polymer (ceramer) is produced through pyrolysis at 600 degrees C. Despite variations in drying methods, polymer and ceramer ambi/aerogels exhibit comparable microstructural characteristics, bulk density, pore size and volume, and specific surface area (542-841 m(2) g(-1)). Polymeric and ceramer ambigel with 90 vol% total porosity yield a compressive strength, reaching 2.5 MPa, demonstrating a low thermal conductivity of 0.046 W m-1 K-1. Sorption tests are conducted using oil and organic solvents in aqueous media to benefit their high hydrophobicity (112 degrees < theta < 142 degrees). Aerogels exhibit high sorption capacities: 13.17 g g(-1) for sesame oil, 11.74 g g(-1) for toluene, and 9.19 g g(-1) for n-hexane. The sorption rate for the oil is nearly 10 times slower than that for toluene and n-hexane. Regarding regeneration and reusability, polymer and ceramer aerogels show consistent sorption properties cycles tested for n-hexane and toluene.Article Citation - WoS: 2Citation - Scopus: 3Development of Mg-Alginate Based Self Disassociative Bio-Ink for Magnetic Bio-Patterning of 3d Tumor Models(Wiley-v C H verlag Gmbh, 2024) Şahin, Hasan; Arslan Yıldız, Ahu; Sahin, Hasan; Arslan-Yildiz, Ahu; 04.04. Department of Photonics; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyAlginate forms a hydrogel via physical cross-linking with divalent cations. In literature, Ca2+ is mostly utilized due to strong interactions but additional procedures are required to disassociate Ca-alginate hydrogels. On the other hand, Mg-alginate hydrogels disassociate spontaneously, which might benefit certain applications. This study introduces Mg-alginate as the main component of a bio-ink for the first time to obtain 3D tumor models by magnetic bio-patterning technique. The bio-ink contains magnetic nanoparticles (MNPs) for magnetic manipulation, Mg-alginate hydrogel as a sacrificial material, and cells. The applicability of the methodology is tested for the formation of 3D tumor models using HeLa, SaOS-2, and SH-SY5Y cells. Long-term cultures are examined by Live/dead and MTT analysis and revealed high cell viability. Subsequently, Collagen and F-actin expressions are observed successfully in 3D tumor models. Finally, the anti-cancer drug Doxorubicin (DOX) effect is investigated on 3D tumor models, and IC50 values is calculated to assess the drug response. As a result, significantly higher drug resistance is observed for bio-patterned 3D tumor models up to tenfold compared to 2D control. Overall, Mg-alginate hydrogel is successfully used to form bio-patterned 3D tumor models, and the applicability of the model is shown effectively, especially as a drug screening platform.Article Citation - WoS: 10Citation - Scopus: 11Tunable Magnetism in 2d Organic-Ion Mnps<sub>3</Sub> Via Molecule-Dependent Vacancy Generation(Wiley-v C H verlag Gmbh, 2024) Tezze, Daniel; Pereira, Jose M.; Tutar, Dogukan; Ramos, Maria; Regner, Jakub; Gargiani, Pierluigi; Gobbi, Marco; 01. Izmir Institute of TechnologyThe magnetic properties of van der Waals materials are profoundly influenced by structural defects. The layered antiferromagnet MnPS3 offers a unique opportunity to explore defect-related magnetism, as Mn2+ vacancies can be generated by the intercalation of specific guest molecules. However, the effectiveness of this process in atomically thin flakes and the extent of the magnetic tunability remain unclear. Here, it is shown that the magnetic properties of MnPS3 can be tailored through the intercalation of different guest molecules. Notably, the insertion of four alkylammonium ions introduces different populations of Mn2+ vacancies, leading to a transition from the pristine antiferromagnetic state to more complex magnetic textures, including a ferrimagnetic state displaying a magnetic saturation of 1 mu B per atom. Moreover, it is shown that the intercalation of few-nm-thick flakes also leads to the emergence of a ferrimagnetic response. This in-flake intercalation, which can be monitored in real time using optical microscopy, can be interrupted before completion, generating lateral heterostructures between pristine and intercalated areas. This approach opens the way to the use of partial intercalation to define regions with distinct magnetic properties within a single flake.Article Improving the Device Stability by Controlling the Morphology of Quantum Dot Emissive Layer Via a Coating Process in Blue Qleds(Wiley-v C H verlag Gmbh, 2024) Özçelik, Serdar; Varlıklı, Canan; Diker, Halide; Ozcelik, Serdar; Varlikli, Canan; 01. Izmir Institute of Technology; 04.01. Department of Chemistry; 04.04. Department of Photonics; 04. Faculty of ScienceBlue light-emitting CdSe@ZnS/ZnS quantum dot (QD) nanoparticles (NPs) were synthesized and their photophysical properties in both solution and film phases were investigated. The morphological properties of films prepared by different coating methods i. e. single layer coating from low to high concentrations of QD solutions and layer-by-layer (multilayer) coating within constant low QD solution concentration, were also examined in detail. Varying the concentration (1-10 mg/mL) and the number of layers (from 1-16) did not essentially affect the photophysical properties of QD films, although it resulted in a direct increment in QD film thickness. The concentration and layer-dependent films were used as an emissive layer (EML) in QD light-emitting diodes (QLEDs). Although the "6 mg/ml(-1) Layer" QD EML-based device exhibited relatively high device efficiency compared to the "1 mg/ml(-10) Layers" based one at working voltage region, it had similar to 2-fold higher efficiency roll-off at high voltage region. The performance differences for both devices with the same QD EML thickness were attributed to the morphological variations for the QD layer in terms of surface roughness, void density, aggregates/clusters, and trap sites that were directly related to the charge injection balance and Auger recombination.