Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Review Citation - WoS: 5Citation - Scopus: 5Development and Functionalization of Electrospun Fiber Coated Thin Film Microextraction Devices for Rapid Mass Spectrometric Determination of Biologically Important Polar Molecules(Elsevier B.V., 2024) Öztürk,M.; Salih,B.; Eroğlu,A.E.; Boyaci,E.Rapid diagnosis of diseases is one of the challenging areas in clinical research. From the analytical chemist's perspective, the main challenges are isolating the compounds from the bio-specimen and lengthy analysis times. In this regard, solid phase microextraction offers a platform to address the abovementioned challenges. Moreover, its sharp tip-thin film geometry, known as coated blade spray (CBS), can enhance the extraction and act as an ionization source in direct mass spectrometric analysis. In this study, a new CBS device specifically designed for polar analytes was prepared and optimized to determine urinary metabolites. For this purpose, polyacrylonitrile (PAN) was selected as a base polymer as it can be electrospun to form a nanofibrous structure, and it can be modified with weak ion exchange moieties to interact with polar analytes. Following the electrospinning of PAN, hydrolysis was optimized, and conditions leading to sufficient extraction enhancement without dissolving the polymer were obtained when probes were treated with 5.0 M of NaOH for 2.5 h. Using the coated blades prepared as explained, the evaluation of various extraction conditions showed that 5 min is sufficient for equilibrium extraction. In addition, the solution's ionic strength and pH significantly affect the extraction. Optimum sorption was obtained at no salt added and pH 7.0 conditions. The CBS-MS optimization showed that 10.0 µL of ACN/MeOH/H2O (40:40:20, v/v/v) with formic acid kept for 15 seconds on the blade before voltage application leads to the highest signal. The limits of quantification of the analytes are between 50 and 100 ng/mL. © 2024 Elsevier B.V.Article Citation - WoS: 3Citation - Scopus: 5Physically Unclonable Security Patterns Created by Electrospinning, and Authenticated by Two-Step Validation Method(IOP Publishing, 2022) Taşcıoğlu, Didem; Atçı, Arda; Sevim Ünlütürk, Seçil; Özçelik, SerdarCounterfeiting is a growing economic and social problem. For anticounterfeiting, random and inimitable droplet/fiber patterns were created by the electrospinning method as security tags that are detectable under UV light but invisible in daylight. To check the authenticity of the original security patterns created; images were collected with a simple smartphone microscope and a database of the recorded original patterns was created. The originality of the random patterns was checked by comparing them with the patterns recorded in the database. In addition, the spectral signature of the patterns in the droplet/fiber network was obtained with a simple and hand-held spectrometer. Thus, by reading the spectral signature from the pattern, the spectral information of the photoluminescent nanoparticles was verified and thus a second-step verification was established. In this way, anticounterfeiting technology that combines ink formula, unclonable security pattern creation and two-level verification is developed.Article Citation - WoS: 17Citation - Scopus: 20Electrospun Polyacrylonitrile (pan) Nanofiber: Preparation, Experimental Characterization, Organic Vapor Sensing Ability and Theoretical Simulations of Binding Energies(Springer, 2022) İnce Yardımcı, Atike; Yağmurcukardeş, Nesli; Yağmurcukardeş, Mehmet; Çapan, İnci; Erdoğan, Matem; Çapan, Rıfat; Tarhan, Özgür; Açıkbaş, YaserIn this study, polyacrilonitrile (PAN) nanofibers obtained by electrospinning were directly coated on the surface of a quartz crystal microbalance (QCM) and were investigated for their sensing characteristics against chloroform, dichloromethane and carbon tetrachloride as volatile organic compounds (VOCs). PAN nanofibers were characterized by SEM, DSC, Raman Spectroscopy, and FT-IR and the results indicated that beadless and regular nanofibers with the average diameter of 182.7 ± 32 nm were obtained. Kinetic measurements indicated that electrospun PAN nanofibers were sensitive to the VOCs and they were appropriate for sensing applications of chlorine compounds. The reproducibility of PAN nanofiber sensor was also shown in this study. The results revealed that the diffusion coefficients of VOCs increased with the order carbontetrachloride < dichloromethane < chloroform which was supported by the density functional theory (DFT) simulations that revealed the highest binding energy for chloroform.Article Citation - WoS: 14Citation - Scopus: 16Bodipy-Based Organic Color Conversion Layers for Wleds(Elsevier, 2020) Yüce, Hürriyet; Güner, Tuğrul; Dartar, Suay; Kaya, Beraat Umur; Emrullahoğlu, Mustafa; Demir, Mustafa MuammerThe usage of organic dyes in phosphor conversion layer of WLED is an attractive approach since they have high molar extinction coefficient and photostability. Various types of organic pigments have been employed for this purpose such as BODIPY, perylene diimide, Rhodamine B, pyrene, Nile red, etc. Among those, BODIPY-based organic dyes appear to be promising candidate for white light generation. In this work, for the first time, red and green emitting BODIPY-based organic molecules have been used as colour conversion layer. These molecules were associated with PMMA in DMF solution and the resulting solution was subjected to electrospinning. Colorful electrospun mats were embedded into PDMS matrix and their free-standing PDMS composite films were used as color conversion layers over blue LED to produce white light such that CRI of 95 and CCT of 4200 K was achieved. These values show that BODIPY-based organic molecules containing fiber composites are promising candidates to be used as color conversion layers for white light applications.Article Citation - WoS: 27Citation - Scopus: 28Biocomposite Scaffolds for 3d Cell Culture: Propolis Enriched Polyvinyl Alcohol Nanofibers Favoring Cell Adhesion(John Wiley and Sons Inc., 2021) Bilginer, Rumeysa; Özkendir İnanç, Dilce; Yıldız, Ümit Hakan; Arslan Yıldız, AhuThe objective of this work is generation of propolis/polyvinyl alcohol (PVA) scaffold by electrospinning for 3D cell culture. Here, PVA used as co-spinning agent since propolis alone cannot be easily processed by electrospinning methodology. Propolis takes charge in maximizing biological aspect of scaffold to facilitate cell attachment and proliferation. Morphological analysis showed size of the electrospun nanofibers varied between 172-523 nm and 345-687 nm in diameter, for non-crosslinked and crosslinked scaffolds, respectively. Incorporation of propolis resulted in desired surface properties of hybrid matrix, where hybrid scaffolds highly favored protein adsorption. To examine cell compatibility, NIH-3T3 and HeLa cells were seeded on propolis/PVA hybrid scaffold. Results confirmed that integration of propolis supported cell adhesion and cell proliferation. Also, results indicated electrospun propolis/PVA hybrid scaffold provide suitable microenvironment for cell culturing. Therefore, developed hybrid scaffold could be considered as potential candidate for 3D cell culture and tissue engineering.Article Citation - WoS: 25Citation - Scopus: 27Osteogenic Differentiation of Mesenchymal Stem Cells on Random and Aligned Pan/Ppy Nanofibrous Scaffolds(SAGE Publications, 2019) Selamet, Yusuf; İnce Yardımcı, Atike; Baskan, Öznur; Yılmaz, Selahattin; Meşe, Gülistan; Özçivici, EnginThe aim of this study was to develop random and aligned polyacrilonitrile (PAN)/polypyrrole (PPy) nanofibrous scaffolds by electrospinning technique for osteogenic differentiation of mesenchymal stem cells. Nanofibers were fabricated successfully as straight, smooth, and free from bead formation. The average diameter of random and aligned nanofibers was 268(+/- 49) nm and 225(+/- 72) nm, respectively. Alignment process increased the tensile strength of nanofibers 3.9-fold, while the tensile strain of nanofibers decreased by 78%. PAN/PPy nanofibers were hydrophilic with the contact angle value of about 32 degrees and alignment did not affect the contact angle value. Random and aligned PAN/PPy nanofibers were investigated as a scaffold material for osteogenic differentiation of D1 ORL UVA mouse bone marrow mesenchymal stem cells. Cells were able to attach and grow on nanofibers confirmed by cell viability results. Stem cells that were cultured with osteogenic induction were able to mineralize on electrospun nanofibers based on alizarin red and Von Kossa dye staining. For aligned PPy nanofibers, mineralization occurred in the fiber alignment direction. Consequently, PAN/PPy nanofibrous mats in both random and aligned forms would be potential candidates for bone tissue engineering.Article Citation - WoS: 69Citation - Scopus: 77Novel Zein-Based Multilayer Wound Dressing Membranes With Controlled Release of Gentamicin(John Wiley and Sons Inc., 2019) Kimna, Ceren; Tamburacı, Sedef; Tıhmınlıoğlu, FundaRecently, functional multilayer scaffolds with controlled drug release ability come into prominence for wound healing applications to mimic the layered structure of skin tissue and prevent the possible infections at the defect site. In this study, controlled antibiotic releasing zein bilayer membranes were fabricated for treatment of acute skin infections. Gentamicin loaded fibers were prepared by electrospinning on the membrane surface. Membranes were characterized with scanning electron microscope, atomic force microscopy, Fourier transform infrared spectroscopy, contact angle, mechanical analysis, swelling, degradation, and water vapor permeability studies. In vitro cytotoxicity, cell attachment, and proliferation were investigated. Cell attachment on fiber layer was observed with fluorescence imaging. Fabricated fibers showed structural similarity to the skin tissue layers with a fiber diameter range of 350-425 nm and film thickness in the range of 311-361 mu m. Mechanical properties were found compatible with the skin tissue. In addition, membranes showed antimicrobial activity against Staphylococcus aureus and Escherichia coli. The sustained release was achieved with a cumulative release of 94%. Membranes did not show any cytotoxic effect. NIH/3T3 and HS2 cell lines were proliferated on each layer mimicking the multilayer skin tissue. Hence, zein-based bilayer membrane showed promising properties to be used as a potential antimicrobial wound dressing for skin tissue regeneration. (c) 2018 Wiley Periodicals, Inc.Article Citation - WoS: 21Citation - Scopus: 24Modification of Electrospun Pva/Paa Scaffolds by Cold Atmospheric Plasma: Alignment, Antibacterial Activity, and Biocompatibility(Springer Verlag, 2019) Arik, Nehir; İnan, Alper; İbiş, Fatma; Demirci, Emine A.; Karaman, Ozan; Ercan, Utku K.; Horzum, NesrinThe ongoing search for better antibacterial wound care dressings has led to the design and fabrication of advanced functional nanomaterials. Taking advantage of electrospinning and cold atmospheric plasma (CAP), free-standing nanofibrous scaffolds are promising for use in novel biomedical applications. Random and aligned polyvinyl alcohol (PVA)/polyacrylic acid (PAA) nanofiber scaffolds are fabricated by electrospinning and treated with CAP. In this study, we investigate the effects of CAP treatment on alignment, hydrophilicity, antibacterial activity, and biocompatibility in determining the surface properties of the nanofibrous scaffolds. The results of vibrational polarization spectroscopy analysis indicate that CAP treatment changes the degree of alignment of the nanofibers. Furthermore, both random and aligned CAP-treated nanofibrous scaffolds show significant antibacterial activity against the E. coli strain. The results of an in vitro scratch assay reveal that CAP treatment of PVA/PAA nanofibers has no toxic effect.Article Citation - WoS: 18Citation - Scopus: 14Optimization and Performance of Nitrogen-Doped Carbon Dots as a Color Conversion Layer for White-Led Applications(Beilstein-Institut Zur Forderung der Chemischen Wissenschaften, 2019) Güner, Tuğrul; Yüce, Hürriyet; Taşçıoğlu, Didem; Şimşek, Eren; Savacı, Umut; Genç, Aziz; Demir, Mustafa MuammerIn this study, green-emitting nitrogen-doped carbon dots (N-CDots) were synthesized and incorporated into drop-cast composite films for use as color conversion layers in a white-LED configuration to generate white light. In order to resolve the red deficiency of this configuration, a commercial red phosphor was integrated into the system. Moreover, the N-CDots were also processed into polymer/N-CDot composite fibers, for which we determined the amount of N-CDots that yielded adequate white-light properties. Finally, we showed that white light with excellent properties could be generated by employing both of the fabricated N-CDot composites either as drop-cast films or composite fibers. Hence, N-CDots provide a promising alternative to inorganic phosphors that are commonly employed in white-LED configurations.Article Citation - WoS: 12Citation - Scopus: 17Fish Scale/Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Nanofibrous Composite Scaffolds for Bone Regeneration(SAGE Publications, 2020) Kara, Aylin; Güneş, Oylum C.; Albayrak, Aylin Z.; Bilici, Gökçen; Erbil, Güven; Havitcioğlu, HasanThe aim of this study was to produce three-dimensional, nanofibrous fish scale/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) composite scaffolds as bone filling materials. This is the first report wherein fish scales were used within a nanofibrous matrix for bone regeneration. Composite scaffolds with a cotton wool-like structure (fiber diameter: 560 +/- 64 nm; porosity: 82%) were obtained by incorporating chopped fish scales into wet-electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanofibers and freeze-drying. The addition of the fish scales improved the mechanical properties, biomineralization tendency, cell viability, alkaline phosphatase activity, and type I collagen production. Consequently, produced composite scaffolds would be regarded to have the therapeutic capacity in bone tissue damages.