62 results match your criteria: "Koc University Surface Science and Technology Center[Affiliation]"
Macromol Rapid Commun
July 2023
Department of Chemical and Biological Engineering, Koc University, Sariyer, Istanbul, 34450, Turkey.
Shear forces are involved in many cellular processes and increase remarkably in the case of cardiovascular diseases in the human body. While various stimuli, such as temperature, pH, light, and electromagnetic fields, have been considered for on-demand release, developing drug delivery systems that are responsive to physiological-level shear stresses remains as a challenge. For this purpose, liposomes embedded in hydrogel matrices are promising as they can dynamically engage with their environment due to their soft and deformable structure.
View Article and Find Full Text PDFACS Appl Energy Mater
April 2023
Department of Chemical and Biological Engineering, Koç University, Sariyer, Istanbul 34450, Türkiye.
Poly(ethylene oxide) (PEO)-based polymer electrolytes are a promising class of materials for use in lithium-ion batteries due to their high ionic conductivity and flexibility. In this study, the effects of polymer architecture including linear, star, and hyperbranched and salt (lithiumbis(trifluoromethanesulfonyl)imide (LiTFSI)) concentration on the glass transition ( ), microstructure, phase diagram, free volume, and bulk viscosity, all of which play a significant role in determining the ionic conductivity of the electrolyte, have been systematically studied for PEO-based polymer electrolytes. The branching of PEO widens the liquid phase toward lower salt concentrations, suggesting decreased crystallization and improved ion coordination.
View Article and Find Full Text PDFTalanta
July 2023
Department of Chemistry, Sharif University of Technology, Tehran, 111559516, Iran; Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, 11155-9516, Iran. Electronic address:
Most nanoparticle based colorimetric sensor array utilize several sensor elements and static response for discrimination of target analytes. This approach can be complicated and costly to synthesize or functionalize different nanoparticles for providing wide color variation. Herein, triangular silver nanoparticles (TSNPs) were used to develop a colorimetric sensor array by time-dimension responses.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2023
Department of Chemical and Biological Engineering, Koç University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey.
Considering the existence of a large number and variety of metal-organic frameworks (MOFs) and ionic liquids (ILs), assessing the gas separation potential of all possible IL/MOF composites by purely experimental methods is not practical. In this work, we combined molecular simulations and machine learning (ML) algorithms to computationally design an IL/MOF composite. Molecular simulations were first performed to screen approximately 1000 different composites of 1--butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF]) with a large variety of MOFs for CO and N adsorption.
View Article and Find Full Text PDFACS Omega
March 2023
Chemistry Department, Koc University, Rumelifeneri yolu, Sariyer, 34450 Istanbul, Turkey.
In the present work, unilamellar [SrTaO] perovskite nanosheets with variable lateral dimensions were synthesized via a high-yield, three-step liquid exfoliation route from layered BiSrTaO. The photocatalytic activity of the parent and exfoliated layered perovskites was evaluated for the photocatalytic dye degradation of Rhodamine B under UV light (254 nm) and reduction of water to H under the full solar spectrum. A comparative study of the photocatalytic behavior of unilamellar [SrTaO] perovskite nanosheets and parent layered structure showed a significant improvement in both hydrogen evolution (98.
View Article and Find Full Text PDFMembranes (Basel)
June 2022
Department of Chemical and Biological Engineering, Koc University, Sariyer, Istanbul 34450, Turkey.
Understanding dynamic and complex interaction of biological membranes with extracellular matrices plays a crucial role in controlling a variety of cell behavior and functions, from cell adhesion and growth to signaling and differentiation. Tremendous interest in tissue engineering has made it possible to design polymeric scaffolds mimicking the topology and mechanical properties of the native extracellular microenvironment; however, a fundamental question remains unanswered: that is, how the viscoelastic extracellular environment modifies the hierarchical dynamics of lipid membranes. In this work, we used aqueous solutions of poly(ethylene glycol) (PEG) with different molecular weights to mimic the viscous medium of cells and nearly monodisperse unilamellar DMPC/DMPG liposomes as a membrane model.
View Article and Find Full Text PDFBiomater Sci
July 2022
Department of Chemistry, Koc University, Rumelifeneri Yolu, Sariyer, Istanbul 34450, Türkiye.
Etoposide (Eto) is a toxic drug that shows promise in treating prostate cancer (PCa) but confers significant side effects, and has poor solubility and bioavailability. Nanoparticles are quite successful in overcoming such problems. Multifunctional nanoparticles that provide an opportunity to perform combination therapy have attracted great interest in recent years.
View Article and Find Full Text PDFPhys Chem Chem Phys
May 2022
Bogazici University, Faculty of Arts and Science, Department of Chemistry, 34342, Bebek, Istanbul, Turkey.
Recently, ionic liquids (ILs) have been used as ligands for single-site Ir(CO) complexes bound to metal-oxide supports because of their electron-donor/acceptor capacities. The combined effects of supports and ILs as ligands may pave the way to the tuning of the surrounding electronic properties to increase electron-donor/acceptor efficiency in metal-oxide supported Ir(CO) complexes. Herein, we have used Density Functional Theory to model Ir(CO) complexes bound to MgO supports with and without the presence of an IL to explain the role of ILs in modifying the electronic structure of the supported complex.
View Article and Find Full Text PDFElife
March 2022
Department of Physics, Koç University, Istanbul, Turkey.
During colony growth, complex interactions regulate the bacterial orientation, leading to the formation of large-scale ordered structures, including topological defects, microdomains, and branches. These structures may benefit bacterial strains, providing invasive advantages during colonization. Active matter dynamics of growing colonies drives the emergence of these ordered structures.
View Article and Find Full Text PDFJ Hazard Mater
February 2022
Department of Chemical Engineering, Bogazici University, Bebek, 34342 Istanbul, Turkey. Electronic address:
A novel, cheap, and easy-to-synthesize sepiolite-based alkali-activated material (Sep-AAM), synthesized by the reaction of a magnesium silicate source, sepiolite, with sodium silicate solution, demonstrating high mechanical strength and methylene blue (MB) removal performance is introduced. Kinetics data indicated that MB adsorption occurs through pseudo-second-order adsorption kinetics model, while the Langmuir isotherm model provided a better fit to adsorption isotherms. The Sep-AAM provided a removal capacity of 99.
View Article and Find Full Text PDFJ Phys Chem B
October 2021
Koç University Surface Science and Technology Center (KUYTAM), Rumelifeneri, Istanbul 34450, Turkey.
Nanoparticles have become popular photosensitizers for photothermal therapy (PTT), as they can be targeted to specific cancer tissues and deliver a chemotherapeutic drug, providing a multimodal therapeutic approach. Photothermal conversion efficiency of nanoparticles is critical in the assessment of their therapeutic use in PTT. We describe an accurate calorimetric method for the determination of the photothermal conversion efficiency of nanoparticles in solution.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2021
Department of Biomedical Science and Engineering, Koç University, Istanbul 34450, Turkey.
It is a generally accepted perspective that type-II nanocrystal quantum dots (QDs) have low quantum yield due to the separation of the electron and hole wavefunctions. Recently, high quantum yield levels were reported for cadmium-based type-II QDs. Hence, the quest for finding non-toxic and efficient type-II QDs is continuing.
View Article and Find Full Text PDFFront Chem
January 2021
Koç University TÜPRAS Energy Center (KUTEM), Koç University, Istanbul, Turkey.
We incorporated a water-stable ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF], into a water-stable metal-organic framework (MOF), MIL-53(Al), to generate the [BMIM][PF]/MIL-53(Al) composite. This composite was examined for water purification by studying its capacity for methylene blue (MB) and methyl orange (MO) removal from aqueous solutions having either single dye or a mixture of both. Data illustrated that the removal efficiency and the maximum adsorption capacity of MIL-53(Al) were increased several times upon [BMIM][PF] incorporation.
View Article and Find Full Text PDFSci Rep
February 2021
Koç University Boron and Advanced Materials Application and Research Center (KUBAM), 34450, Sariyer, Istanbul, Turkey.
Growing environmental problems along with the galloping rate of population growth have raised an unprecedented challenge to look for an ever-lasting alternative source of energy for fossil fuels. The eternal quest for sustainable energy production strategies has culminated in the electrocatalytic water splitting process integrated with renewable energy resources. The successful accomplishment of this process is thoroughly subject to competent, earth-abundant, and low-cost electrocatalysts to drive the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), preferably, in the same electrolyte.
View Article and Find Full Text PDFJ Photochem Photobiol B
December 2020
Koç University, Graduate School of Materials Science and Engineering, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey; Koç University, Department of Chemistry, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey. Electronic address:
Multifunctional quantum dots (QDs) with photothermal therapy (PTT) potential loaded with an anticancer drug and labelled with a targeting agent can be highly effective nano-agents for tumour specific, image-guided PTT/chemo combination therapy of cancer. Ag-chalcogenides are promising QDs with good biocompatibility. AgS QDs are popular theranostic agents for imaging in near-infrared with PTT potential.
View Article and Find Full Text PDFJ Phys Chem Lett
October 2020
Materials Science and Engineering, Koç University, Istanbul 34450, Turkey.
BiVO is one of the most promising photoanode materials for water-splitting systems. Nitrogen incorporation into a BiVO surface overcomes the known bottleneck in its charge-transfer kinetics into the electrolyte. We explored the role of nitrogen in the surface charge recombination and charge-transfer kinetics by employing transient photocurrent spectroscopy at the time scale of surface recombination and water oxidation kinetics, transient absorption spectroscopy, and X-ray photoelectron spectroscopy.
View Article and Find Full Text PDFJ Phys Condens Matter
September 2020
Department of Chemical and Biological Engineering, Ko̧ University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey.
In this work, we incorporated an ionic liquid (IL), 1--butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO]) into two different metal organic frameworks (MOFs), UiO-66, and its amino-functionalized counterpart, NH-UiO-66, to investigate the effects of ligand-functionalization on the thermal stability limits of IL/MOF composites. The as-synthesized IL/MOF composites were characterized in detail by combining x-ray diffraction, scanning electron microscopy, Brunauer-Emmett-Teller analysis, x-ray fluorescence, infrared spectroscopies (FTIR), and their thermal stability limits were determined by thermogravimetric analysis (TGA). Characterization data confirmed the successful incorporation of the IL into each MOF and indicated the presence of direct interactions between them.
View Article and Find Full Text PDFiScience
July 2020
Graduate School of Materials Science and Engineering, Koç University, Istanbul 34450, Turkey; Department of Biomedical Sciences and Engineering, Koç University, Istanbul 34450, Turkey; Department of Electrical and Electronics Engineering, Koç University, Istanbul 34450, Turkey. Electronic address:
Colloidal quantum dots (QDs) are promising building blocks for luminescent solar concentrators (LSCs). For their widespread use, they need to simultaneously satisfy non-toxic material content, low reabsorption, high photoluminescence quantum yield, and large-scale production. Here, copper doping of zinc carboxylate-passivated InP core and nano-engineering of ZnSe shell facilitated high in-device quantum efficiency of QDs over 80%, having well-matched spectral emission profile with the photo-response of silicon solar cells.
View Article and Find Full Text PDFJ Nanobiotechnology
April 2020
Sabanci University Nanotechnology Research and Application Center (SUNUM), Department of Biotechnology, Tuzla, 34956, Istanbul, Turkey.
Nanoparticle based gene delivery systems holds great promise. Superparamagnetic iron oxide nanoparticles (SPIONs) are being heavily investigated due to good biocompatibility and added diagnostic potential, rendering such nanoparticles theranostic. Yet, commonly used cationic coatings for efficient delivery of such anionic cargos, results in significant toxicity limiting translation of the technology to the clinic.
View Article and Find Full Text PDFElife
April 2020
Bio-Medical Sciences and Engineering Program, Koç University, Sarıyer, Istanbul, Turkey.
Many animals collectively form complex patterns to tackle environmental difficulties. Several biological and physical factors, such as animal motility, population densities, and chemical cues, play significant roles in this process. However, very little is known about how sensory information interplays with these factors and controls the dynamics of pattern formation.
View Article and Find Full Text PDFEnergy Technol (Weinh)
July 2019
1--Butyl-3-methylimidazolium methyl sulfate is incorporated into MIL-53(Al). Detailed characterization is done by X-ray fluorescence, Brunauer-Emmett-Teller surface area, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. Results show that ionic liquid (IL) interacts directly with the framework, significantly modifying the electronic environment of MIL-53(Al).
View Article and Find Full Text PDFData Brief
April 2020
Koc University, School of Medicine, Department of Medical Biochemistry, Sariyer, 34450, Istanbul, Turkey.
Minerals and trace elements play vital role in the biological functions for all organisms including human and other mammals. Therefore, imbalance in the mineral and/or trace element levels may cause formation of several diseases including cancer, diabetes, cardiovascular diseases, and neurological disorders. ICP-MS (inductively coupled plasma - mass spectrometry) is described as the most sensitive and accurate method.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2020
Department of Chemistry, College of Sciences , Koç University, Sarıyer , 34450 , Istanbul , Turkey.
A novel ternary nanocomposite, mesoporous graphitic carbon nitride/black phosphorus-AgPd (denoted mpg-CN/BP-AgPd), was successfully fabricated by assembling the as-prepared AgPd alloy nanoparticles (NPs) on mesoporous graphitic carbon nitride/black phosphorus (mpg-CN/BP) binary composites. This novel nanocomposite comprises a heterojunction support material formed by two distinct nonmetallic semiconductors (mpg-CN and BP) with adaptable band gaps and edge voltages, providing enhanced catalytic activity to AgPd alloy NPs in hydrogen generation from the methanolysis of ammonia borane (AB) compared to its single components under the blue light-emitting diode (LED) light illumination. The yielded mpg-CN/BP-AgPd ternary nanocomposites were characterized by many advanced analytical techniques (transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), time-resolved spectroscopy, inductively coupled plasma-mass spectroscopy (ICP-MS), and fourier transform infrared (FTIR), and then they were tested as catalysts in hydrogen generation from the methanolysis of AB at room temperature.
View Article and Find Full Text PDFAppl Spectrosc
March 2020
Koç University Surface Science and Technology Center (KUYTAM), Rumelifeneri Yolu, Sariyer 34450 Istanbul, Turkey.
Almost all archaeometric studies on Chinese ceramics are carried out on the excavation materials. Therefore, a detailed, comparable database that defines different workshops and production periods already exists. But the masterpieces preserved at museums, art galleries, and/or private collections, which are artistically considered as genuine artifacts, also require similar scientific investigations to define their provenance and authenticity.
View Article and Find Full Text PDFJ Photochem Photobiol B
December 2019
Graduate School of Materials Science and Engineering, Koc University, Rumelifeneri Yolu, Sariyer, Istanbul 34450, Turkey; KUYTAM, Koc University Surface Science and Technology Center, 34450 Istanbul, Turkey; Department of Chemistry, Koc University, Rumelifeneri Yolu, Sariyer, Istanbul 34450, Turkey. Electronic address:
Superparamagnetic iron oxide nanoparticles (SPIONs) have been recently recognized as highly efficient photothermal therapy (PTT) agents. Here, we demonstrate, for the first time to our knowledge, dose and laser intensity dependent PTT potential of small, spherical, 3-aminopropyltrimethoxysilane coated cationic superparamagnetic iron oxide nanoparticles (APTMS@SPIONs) in aqueous solutions upon irradiation at 795 nm. Indocyanine green (ICG) which has been recently used for photodynamic therapy (PDT), was loaded to APTMS@SPIONs to improve the stability of ICG and to achieve an effective mild PTT and PDT (dual therapy) combination for synergistic therapeutic effect on cancer cells via a single laser treatment in the near infrared (NIR).
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