Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 3Citation - Scopus: 3Light-Induced Synthesis of Single-Crystalline Gold Microplates in an Open System(Amer Chemical Soc, 2023) Akkuş, Betül; Mert Balcı, FadimeBottom-up synthesis of large single-crystalline gold microplates is of key importance to catalysis, nanophotonics, bioengineering, and plasmonics. However, easy, low-cost, room-temperature, and high-yield synthesis of large gold microplates with several micrometers in lateral size and a few tens of nanometers in thickness by using photochemical synthesis in an open system is still challenging. We herein report on an easy and cost-effective photochemical synthesis of single-crystalline gold microplates with lateral sizes up to around 40 mu m and tens of nanometers in thickness in a few hours of reaction time in an open system containing a lyotropic liquid crystal, which is formed by self-assembly of 10-lauryl ether in a strong acid, sulfuric acid, along with water. We have found that by changing the reaction parameters, such as the reaction time, the concentration of gold ions in the liquid crystal, etc., the thickness and size of the microplates can be easily controlled. Most importantly, the liquid crystalline phase is completely preserved after completion of the photochemical reaction. The microplates can be easily isolated and transferred to different media such as alcohol and water for further studies, or they can be immediately used on a substrate after completion of the reaction. The results obtained in this study will allow us to understand the growth mechanism of gold microplates in open systems, and they will find applications in a variety of critical areas, such as plasmonics, nanophotonics, and catalysis.Article Citation - WoS: 7Citation - Scopus: 8Lithium Extraction From Aqueous Systems by Λ-mno<sub>2</Sub>-deposited Pu Electrospun Mats(Amer Chemical Soc, 2023) Akgun, Berk; Baba, Alper; Demir, Mustafa M.There has been a strong increase in demand for lithium, so the extraction of lithium from natural water resources has become a remarkable remedy to reduce the harmful environmental impact of conventional lithium extraction processes. One of the most effective methods of separating lithium from natural water sources is adsorption using lithium ion sieves as adsorbents. However, the powdered nature of the adsorbents makes them challenging to process. In this study, flexible and free-standing polyurethane (PU) electrospun mats associated with lambda-MnO2 particles were fabricated to extract lithium from aqueous systems. Bead-free and smooth nanofibers were electrospun from a volumetric mixture of DMF:THF (1:2) at 30 wt % of PU solution. lambda-MnO2 powder was deposited on the electrospun mat by vacuum-assisted deposition. The lithium extraction performance of the mats was found to be 21% using single-layer filtration and increased to 77% with multistage filtration. Moreover, using the optimized conditions, lithium extraction achieved up to 14% in a spiked brine sample taken from Lake Tuz (Central Anatolia, Turkey), where the Mg2+/Li+ ratio is higher than 85.Article Citation - WoS: 7Citation - Scopus: 6Thickness Gradient in Polymer Coating by Reactive Layer-By Assembly on Solid Substrate(Amer Chemical Soc, 2023) Özenler, Sezer; Alkan, Ali Ata; Gunay, Ufuk Saim; Dağlar, Özgün; Durmaz, Hakan; Yıldız, Ümit HakanThe study describes a simple yet robust methodology for forming gradients in polymer coatings with nanometer-thickness precision. The thickness gradients of 0-20 nm in the coating are obtained by a reactive layer-by-layer assembly of polyester and polyethylenimine on gold substrates. Three parameters are important in forming thickness gradients: (i) the incubation time, (ii) the incubation concentration of the polymer solutions, and (iii) the tilt angle of the gold substrate during the dipping process. After examining these parameters, the characterization of the anisotropic surface obtained under the best conditions is presented in the manuscript. The thickness profile and nanomechanical characterization of the polymer gradients are characterized by atomic force microscopy. The roughness analysis has demonstrated that the coating exhibited decreasing roughness with increasing thickness. On the other hand, Young's moduli of the thin and thick coatings are 0.50 and 1.4 MPa, respectively, which assured an increase in mechanical stability with increasing coating thickness. Angle-dependent infrared spectroscopy reveals that the C-O-C ester groups of the polyesters exhibit a perpendicular orientation to the surface, while the C=C groups are parallel to the surface. The surface properties of the polymer gradients are explored by fluorescence microscopy, proving that the dye's fluorescence intensity increases as the coating thickness increases. The significant benefit of the suggested methodology is that it promises thickness control of gradients in the coating as a consequence of the fast reaction kinetics between layers and the reaction time.Article Citation - WoS: 26Citation - Scopus: 27Dopamine-Conjugated Bovine Serum Albumin Nanoparticles Containing Ph-Responsive Catechol-V(iii) Coordination for in Vitro and in Vivo Drug Delivery(Amer Chemical Soc, 2023) Argıtekin, Eda; Ersöz-Gülseven, Esra; Çakan-Akdoğan, Gülçin; Akdoğan, YaşarV(III) instead of commonly used Fe(III) provided a richtris-catechol-metalcoordination at pH 7.4, which is important for slow drug release atphysiological pH. Bovine serum albumin (BSA) functionalized with catechol-containingdopamine (D) and cross-linked using tris-catechol-V(III) coordinationyielded pH-responsive compact D-BSA NPs (253 nm). However, conversionto bis- and/or mono-catechol-V(III) complexes in an acidic mediumresulted in degradation of NPs and rapid release of doxorubicin (DOX).It was shown that D-BSA NPs entered cancerous MCF-7 cells (66%) moreefficiently than non-cancerous HEK293T (33%) in 3 h. Also, DOX-loadedNPs reduced cell viability of MCF-7 by 75% and induced apoptosis ina majority of cells after 24 h. Biodegradability and lack of hemolyticactivity were shown in vitro, whereas a lack of toxicity was shownin histological sections of zebrafish. Furthermore, 30% of circulatingtumor cells in vasculature in 24 h were killed by DOX-loaded NPs shownwith the zebrafish CTC xenograft model.Article Citation - Scopus: 11Fabrication of Helix Aspersa Extract Loaded Gradient Scaffold With an Integrated Architecture for Osteochondral Tissue Regeneration: Morphology, Structure, and in Vitro Bioactivity [1](Amer Chemical Soc, 2023) Tamburaci, Sedef; Perpelek, Merve; Aydemir, Selma; Baykara, Basak; Havitcioğlu, Hasan; Tihminlioğlu, FundaRegeneration of osteochondral tissue with its layered complex structure and limited self-repair capacity has come into prominence as an application area for biomaterial design. Thus, literature studies have aimed to design multilayered scaffolds using natural polymers to mimic its unique structure. In this study, fabricated scaffolds are composed of transition layers both chemically and morphologically to mimic the gradient structure of osteochondral tissue. The aim of this study is to produce gradient chitosan (CHI) scaffolds with bioactive snail (Helix aspersa) mucus (M) and slime (S) extract and investigate the structures regarding their physicochemical, mechanical, and morphological characteristics as well as in vitro cytocompatibility and bioactivity. Gradient scaffolds (CHI-M and CHI-S) were fabricated via a layer-by-layer freezing and lyophilization technique. Highly porous and continuous 3D structures were obtained and observed with SEM analysis. In addition, scaffolds were physically characterized with water uptake test, micro-CT, mechanical analysis (compression tests), and XRD analysis. In vitro bioactivity of scaffolds was investigated by co-culturing Saos-2 and SW1353 cells on each compartment of gradient scaffolds. Osteogenic activity of Saos-2 cells on extract loaded gradient scaffolds was investigated in terms of ALP secretion, osteocalcin (OC) production, and biomineralization. Chondrogenic bioactivity of SW1353 cells was investigated regarding COMP and GAG production and observed with Alcian Blue staining. Both mucus and slime incorporation in the chitosan matrix increased the osteogenic differentiation of Saos-2 and SW1353 cells in comparison to the pristine matrix. In addition, histological and immunohistological staining was performed to investigate ECM formation on gradient scaffolds. Both characterization and in vitro bioactivity results indicated that CHI-M and CHI-S scaffolds show potential for osteochondral tissue regeneration, mimicking the structure as well as enhancing physical characteristics and bioactivity.