PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Temporal Coherence of Single Photons Emitted by Hexagonal Boron Nitride Defects at Room Temperature(Amer Chemical Soc, 2026) Martinez-Pons, Juan Vidal; Kim, Sang Kyu; Behrens, Max; Izquierdo-Molina, Alejandro; Menendez Rua, Adolfo; Pacal, Serkan; Anton-Solanas, CarlosColor centers in hexagonal boron nitride (hBN) emerge as promising quantum light sources at room temperature, with potential applications in quantum communications, among others. The temporal coherence of emitted photons (i.e., their capacity to interfere and distribute photonic entanglement) is essential for many of these applications. Hence, it is crucial to study and determine the temporal coherence of this emission under different experimental conditions. In this work, we report the coherence time of the single photons emitted by an hBN defect in a nanocrystal at room temperature, measured via Michelson interferometry. The visibility of this interference vanishes when the temporal delay between the interferometer arms is a few hundred femtoseconds, highlighting that the phonon dephasing processes are 4 orders of magnitude faster than the spontaneous decay time of the emitter. We also analyze the single photon characteristics of the emission via correlation measurements, defect blinking dynamics, and its Debye-Waller factor. Our room temperature results highlight the presence of a strong electron-phonon coupling, suggesting the need to work at cryogenic temperatures to enable quantum photonic applications based on photon interference.Article Protection of N-Type (Ni,Fe)TiSb Half-Heusler Materials Against Static and Cyclic Oxidation Using a Si-Doped Cr Coating(Amer Chemical Soc, 2025) Gurtaran, Mikdat; Zhang, Zhenxue; Li, Xiaoying; Dong, HanshanIn this study, Cr-Si coatings were deposited on N-type (Ni,Fe)TiSb thermoelectric (TE) materials by using a closed-field unbalanced magnetron sputtering PVD technique. Oxidation behavior was evaluated under both isothermal (static) conditions (500 degrees C for 10 h and 600 degrees C for 50 h) and thermal cycling regimens (500 and 600 degrees C for 10 or 50 1 h cycles). Mass gain, surface morphology, cross-sectional microstructure, elemental distribution, and phase composition were examined by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Regardless of exposure mode, uncoated samples oxidized severely: a duplex scale formed, consisting of an outer TiO2 layer and a subjacent NiSb-rich zone, accompanied by extensive cracking and delamination. In sharp contrast, the Cr-Si coatings remained thermally stable and highly oxidation-resistant, maintaining the substrate's integrity during both static and cyclic tests. After exposure, coated samples showed negligible mass gain, no discernible morphological change, and no mechanical damage, confirming that the Cr-Si layer markedly enhances thermal durability and prevents surface degradation.Article Citation - WoS: 4Citation - Scopus: 4Sulfonated Cellulose: a Strategy for Effective Methylene Blue Sequestration(Amer Chemical Soc, 2025) Toy, Mustafa; Recepoglu, Yasar Kemal; Arar, OzgurThis study investigates the sulfonation modification of cellulose for the removal of methylene blue (MB) from aqueous solutions. The prepared biosorbent was characterized, and its sorption capacity, kinetics, and thermodynamics were systematically evaluated. Fourier-transform infrared (FTIR) spectroscopy analyzed structural modifications, while scanning electron microscopy (SEM) examined the surface properties. The optimal sorbent dosage was determined as 0.05 g. MB removal efficiency increased from 11% at pH 1 to 70% at pH 2, reaching 99% within the pH range of 3 to 7. Kinetic studies revealed rapid sorption, achieving 99% removal within 3 min. Among various isotherm models, the Langmuir model provided the best fit (R 2 = 0.9989), indicating monolayer sorption with a maximum capacity of 37.65 mg/g. Thermodynamic analysis showed negative Delta G degrees values, confirming a spontaneous sorption process, while an enthalpy change (Delta H degrees) of -33.5 kJ/mol indicated exothermic behavior. The entropy change (Delta S degrees) of -82.6 J mol-1<middle dot>K-1 suggested decreased disorder during sorption. Regeneration studies demonstrated that 0.2 M HCl combined with ethanol achieved the highest desorption efficiency, and after three cycles, the MB removal efficiency remained above 99%. The presence of -SO3 - groups played a crucial role in MB sorption via ion exchange and may also contribute through hydrogen bonding, thereby enhancing MB sorption. These findings highlight sulfonated cellulose as an efficient and regenerable biosorbent for MB removal, offering valuable insights into its sorption mechanisms.Article Citation - WoS: 7Citation - Scopus: 7Periodate-Mediated Cross-Linking for the Preparation of Catechol Conjugated Albumin Nanoparticles Used for in Vitro Drug Delivery(Amer Chemical Soc, 2025) Argitekin, Eda; Erez, Ozlem; Cakan-Akdogan, Gulcin; Akdogan, YasarConjugation of serum albumin protein with catechol-containing dopamine molecules provides an alternative method for the preparation of albumin nanoparticles (NPs). A commonly used desolvation method utilizes glutaraldehyde as a cross-linking agent. Here, the catechol cross-linking mechanism is used instead of glutaraldehyde providing advantages to prevent toxicity and an undesirable reaction of glutaraldehyde with cargo molecules. Covalent cross-linking between dopamine conjugated bovine serum albumin (D-BSA) proteins was obtained in the presence of sodium periodate (NaIO4) as an oxidizer. As a result, spherical D-BSA NPs with a uniform size distribution of around 100 nm in diameter and negative zeta potential around -28 mV were prepared. Optimal conditions were reached when a dopamine:IO4 - molar ratio of 2:1, pH 7.4 of the medium, and acetone as the desolvating agent were used. Furthermore, the obtained NPs display antioxidant properties, have rapid biodegradability in the presence of trypsin, and have a high doxorubicin (DOX) loading (9.1%) with a sustainable drug release. DOX loaded D-BSA NPs also caused up to 90% breast cancer cell (MCF-7) death within 24 h. These results show that drug carrying albumin NPs can alternatively be prepared via covalently cross-linked catechol groups and used in drug delivery studies.Article Radially Aligned Carbon Nanotube Glass Fiber Composites as Ion-Selective Microelectrodes(Amer Chemical Soc, 2025) Onder, Ahmet; Ng, Zhi Kai; Tsang, Siu Hon; Alagappan, Palaniappan; Teo, Edwin Hang Tong; Yildiz, Umit HakanDetection of ions is challenging due to their small size, rapid diffusion, and high mobility, especially for assaying in samples of low volumes. Among the traditional analytical methods, potentiometric ion-selective electrodes (ISE) have become a popular choice for detecting ions as they are cost-effective, user-friendly and can be miniaturized, making them useful for on-site analysis. In this context, radially aligned carbon nanotubes (RACNT) directly grown on glass fibers (GF) via the chemical vapor deposition method is investigated as a solid contact material for the fabrication of ion-selective microelectrodes (mu ISE) upon incorporating specific ionophores within a polymeric encapsulation membrane. As an illustration, sensitive detection of ammonium ions is accomplished by the fabricated mu ISE (plasticized PVC membrane containing nonactin ionophores), which yielded a LOD and a linear response range between 7.5 x 10-6 and 1.0 x 10-5 to 1.0 x 10-1 M, respectively. The mu ISE fabricated with RACNT-GF as an interface material exhibited improvements in LOD and enhanced the detection selectivity as compared to a conventional ISE fabricated using planar solid contact materials such as graphite. We hypothesize that the fabricated mu ISE with a high surface area and mechanical durability maximize the accommodation of ionophores in the barrier membrane for yielding improved potentiometric responses. Experimental results illustrate that the mu ISE possesses the potential to be utilized for the fabrication of selective and sensitive ISE upon incorporation of specific ionophores with RACNT-GF composites.Article Citation - WoS: 2Citation - Scopus: 2Fabrication of Bioactive Helix Aspersa Extract-Loaded Chitosan-Based Bilayer Wound Dressings for Skin Tissue Regeneration(Amer Chemical Soc, 2024) Perpelek, Merve; Tıhmınlıoğlu, Funda; Tamburaci, Sedef; Karakasli, Ahmet; Tihminlioglu, FundaIn recent years, there has been a notable shift toward exploring plant and animal extracts for the fabrication of tissue engineering structures that seamlessly integrate with the human body, providing both biological compatibility and physical reinforcement. In this particular investigation, we synthesized bilayer wound dressings by incorporating snail (Helix aspersa) secretions, comprising mucus and slime, into chitosan matrices via lyophilization and electrospinning methodologies. A nanofiber layer was integrated on top of the porous structure to mimic the epidermal layer for keratinocyte activity as well as acting as an antibacterial barrier against possible infection, whereas a porous structure was designed to mimic the dermal microenvironment for fibroblast activity. Comprehensive assessments encompassing physical characterization, antimicrobial efficacy, in vitro bioactivity, and wound healing potential were conducted on these bilayer dressings. Our findings revealed that the mucus and slime extract loading significantly altered the morphology in terms of nanofiber diameter and average pore size. Snail extracts loaded on a nanofiber layer of bilayer dressings showed slight antimicrobial activity against Staphylococcus epidermidis and Escherichia coli. An in vitro release study of slime extract loaded in the nanofiber layer indicated that both groups 1 and 2 showed a burst release up to 6 h, and a sustained release was observed up to 96 h for group 1, whereas slime extract release from group 2 continued up to 72 h. In vitro bioactivity assays unveiled the favorable impact of mucus and slime extracts on NIH/3T3 fibroblast and HS2 keratinocyte cell attachment, proliferation, and glycosaminoglycan synthesis. Furthermore, our investigations utilizing the in vitro scratch assay showcased the proliferative and migratory effects of mucus and slime extracts on skin cells. Collectively, our results underscore the promising prospects of bioactive snail secretion-loaded chitosan constructs for facilitating skin regeneration and advancing wound healing therapies.Article Citation - WoS: 1Comparison of Cell-Penetrating and Fusogenic Tat-Ha2 Peptide Performance in Peptideplex, Multicomponent, and Conjugate Sirna Delivery Systems(Amer Chemical Soc, 2024) Uz, Metin; Bulmus, Volga; Altinkaya, Sacide AlsoyIn this study, the performance of the cell-penetrating and fusogenic peptide, TAT-HA2, which consists of a cell-permeable HIV trans-activator of transcription (TAT) protein transduction domain and a pH-responsive influenza A virus hemagglutinin protein (HA2) domain, was comparatively evaluated for the first time in peptideplex, multicomponent, and conjugate siRNA delivery systems. TAT-HA2 in all three systems protected siRNA from degradation, except in the conjugate system with a low Peptide/siRNA ratio. The synergistic effect of different peptide domains enhanced the transfection efficiency of multicomponent and conjugate systems compared to that of peptideplexes, which was attributed to the surface configuration of TAT-HA2 peptides depending on the nature of attachment. Particularly, the multicomponent system showed better cellular uptake and endosomal escape than the peptideplexes, resulting in enhanced siRNA delivery in the cytoplasm. In addition, the presence of cleavable disulfide bonds in multicomponent and conjugate systems promoted the effective siRNA delivery in the cytoplasm, resulting in improved gene silencing activity. The multicomponent system reduced the level of luciferase expression in SKOV3 cells to 45% (+/- 4). In contrast, the conjugate system and the commercially available siRNA transfection agent, Lipofectamine RNAiMax, caused luciferase suppression down to 55% (+/- 2) at a siRNA dose of 100 nM. For the same dose, the peptideplex system could only reduce the luciferase expression to 65% (+/- 5). None of the developed systems showed significant toxicity at any dose. Overall, the TAT-HA2 peptide is promising as a siRNA delivery vector; however, its performance depends on the nature of attachment and, as a result, its surface configuration on the developed delivery system.Article Citation - WoS: 22Citation - Scopus: 12Polarization Dynamics of Solid-State Quantum Emitters(Amer Chemical Soc, 2024) Kumar, Anand; Samaner, Caglar; Cholsuk, Chanaprom; Matthes, Tjorben; Pacal, Serkan; Oyun, Yagiz; Vogl, TobiasQuantum emitters in solid-state crystals have recently attracted a great deal of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that plays a crucial role in various applications, such as quantum computation, which uses the indistinguishability of photons. However, the degree of single-photon polarization is typically quantified using the time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single-photon sources to reveal the origin and temporal evolution of the dipole orientation in solid-state quantum emitters. The angles of the excitation and emission dipoles relative to the crystal axes were determined experimentally and then calculated using density functional theory, which resulted in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics revealed a strongly modified linear polarization visibility that depends on the excited-state decay time of the individual excitation. This effect can potentially be traced back to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further improve the performance of polarization-sensitive experiments, particularly that for quantum communication with single-photon emitters.Article Citation - WoS: 10Citation - Scopus: 9Exploring Neuronal Differentiation Profiles in Sh-Sy5y Cells Through Magnetic Levitation Analysis(Amer Chemical Soc, 2024) Kartal, Rumeysa Bilginer; Yildiz, Ahu ArslanMagnetic levitation (MagLev) is a powerful and versatile technique that can sort objects based on their density differences. This paper reports the sorting of SH-SY5Y cells for neuronal differentiation by the MagLev technique. Herein, SH-SY5Y cells were differentiated with retinoic acid (RA) and brain-derived neurotrophic factor (BDNF). Neuronal differentiation was confirmed by neurite extension measurement and the immunostaining assay. Neurites reached the maximum length on day 9 after sequential treatment with RA-BDNF. Neuronal marker expression of un-/differentiated cells was investigated by beta-III tubulin and neuronal nuclei (NeuN) and differentiated cells exhibited a higher fluorescence intensity compared to un-/differentiated cells. MagLev results revealed that the density of differentiated SH-SY5Y cells gradually increased from 1.04 to 1.06 g/mL, while it remained stable at 1.05 g/mL for un-/differentiated cells. These findings signified that cell density would be a potent indicator of neuronal differentiation. Overall, it was shown that MagLev methodology can provide rapid, label-free, and easy sorting to analyze the differentiation of cells at a single-cell level.Article Citation - WoS: 17Citation - Scopus: 18Utilizing Magnetic Levitation To Detect Lung Cancer-Associated Exosomes(Amer Chemical Soc, 2024) Sozmen, Alper Baran; Arslan-Yildiz, AhuExtracellular vesicles, especially exosomes, have attracted attention in the last few decades as novel cancer biomarkers. Exosomal membrane proteins provide easy-to-reach targets and can be utilized as information sources of their parent cells. In this study, a MagLev-based, highly sensitive, and versatile biosensor platform for detecting minor differences in the density of suspended objects is proposed for exosome detection. The developed platform utilizes antibody-functionalized microspheres to capture exosomal membrane proteins (ExoMPs) EpCAM, CD81, and CD151 as markers for cancerous exosomes, exosomes, and non-small cell lung cancer (NSCLC)-derived exosomes, respectively. Initially, the platform was utilized for protein detection and quantification by targeting solubilized ExoMPs, and a dynamic range of 1-100 nM, with LoD values of 1.324, 0.638, and 0.722 nM for EpCAM, CD81, and CD151, were observed, respectively. Then, the sensor platform was tested using exosome isolates derived from NSCLC cell line A549 and MRC5 healthy lung fibroblast cell line. It was shown that the sensor platform is able to detect and differentiate exosomal biomarkers derived from cancerous and non-cancerous cell lines. Overall, this innovative, simple, and rapid method shows great potential for the early diagnosis of lung cancer through exosomal biomarker detection.