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: 2Design and Evaluation of Novel Poly (Vinyl Alcohol)-Based Electrospun Nanofibers Bearing Quaternized Zinc Phthalocyanine with Improved Antibacterial Efficiency(Elsevier Sci Ltd, 2025) Yavuz, Ozgur; Cakir, Neslihan Turhan; Alcay, Yusuf; Kadi, Ilayda Hizir; Kahveci, Muhammet U.; Yilmaz, Ismail; Altinkok, CagatayElectrospinning of macrocyclic compounds offers a versatile route to functional nanofibers for biomedical applications. However, the small molecular size and tendency to aggregate of such compounds often preclude their direct processing. Herein, we report the fabrication of poly(vinyl alcohol) (PVA) nanofibers uniformly embedded with a dimethylaminophenyl-functionalized, quaternized zinc phthalocyanine derivative (Q-DMAPZnPc) via a straightforward aqueous electrospinning process. Successful incorporation of Q-DMAPZnPc into the PVA matrix was confirmed by FT-IR and 1H NMR spectroscopies. SEM revealed bead-free fibers with average diameters decreasing from 152 +/- 20 nm to 110 +/- 23 nm as the Q-DMAPZnPc loading increased. Water contact angle, thermogravimetric, and differential scanning calorimetry analyses demonstrated that both hydrophilicity and thermal stability of the fibers improved with higher Q-DMAPZnPc content. The singlet oxygen quantum yield (Phi Delta) of the PVA-Q-DMAPZnPc (5 wt %) was measured as 0.35. Importantly, quaternization endowed the fibers with potent antibacterial activity: under visible-light irradiation, PVA-Q-DMAPZnPc mats achieved significant log-reduction against both Gram-negative (Escherichia coli, Salmonella typhimurium) and Gram-positive (Staphylococcus aureus, Bacillus cereus) pathogens, markedly outperforming neat PVA controls. These findings highlight the promise of Q-DMAPZnPc-loaded PVA nanofibers as light-activated antimicrobial platforms for next-generation therapeutic and protective materials.Article Citation - WoS: 1Citation - Scopus: 1Fabrication of Electrospun Polycaprolactone Nanofibrous Mats Loaded With Purple Basil Extract (Ocimum Basilicum L.) as Colorimetric Ph Indicator Films(Springer, 2025) Erez, Elif; Eroglu, Ahmet Emin; Bayramoglu, BesteIntelligent packaging with colorimetric pH indicators revolutionizes traditional food packaging by enabling real-time food quality monitoring. This study used electrospinning to develop pH indicator films from polycaprolactone (PCL) incorporating purple basil extract (PBE). Nanofibrous films containing 0.2% PBE (PCLN_0.2PBE), 0.4% PBE (PCLN_0.4PBE), and 0.6% PBE (PCLN_0.6PBE) were fabricated using different electrospinning conditions. The PCLNs fabricated with a voltage of 20 kV and a flow rate of 1.6 mL/h exhibited the most uniform and bead-free morphology according to scanning electron microscopy. The chemical, thermal, mechanical, and wetting characterization of the films was performed by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, texture analysis, and contact angle analysis, respectively. Both PCLN_0.4PBE and PCLN_0.6PBE films displayed fast (4-5 s) and clear color transitions (Delta E > 3.5) to successive pH buffers within the range critical for food deterioration, while they exhibited excellent color changes (Delta E > 5) for pH variations of at least two units. The PCLN_0.6 PBE film displayed a Delta E of similar to 5 in only 5 min of exposure to ammonia vapor, whereas PCLN_0.4PBE showed a similar color change for over 15 min. The interaction between the films and acidic and alkaline semi-solid foods was simulated using gelatin gels at pH 2.5 and 11, respectively. Both films displayed significant color transitions (Delta E > similar to 9) within 15 min of contact with the gels, with the response from PCLN_0.6 PBE being more pronounced. The color stability in both films was maintained for up to 14 days at 4 degrees C, offering potential early warnings against food spoilage. PBE release was evaluated against different food simulants. The highest release occurred in 50% ethanol; the films demonstrated resistance to 3% acetic acid. The findings indicate that electrospun PCL films integrated with PBE have a promising potential to serve as colorimetric pH indicators for monitoring the freshness of food products.Article Citation - WoS: 7Citation - Scopus: 7Improving Mechanical Behavior of Adhesively Bonded Composite Joints by Incorporating Reduced Graphene Oxide Added Polyamide 6,6 Electrospun Nanofibers(Elsevier Sci Ltd, 2024) Yeke, Melisa; Barisik, Murat; Tanoglu, Metin; Ulas, M. Erdal; Nuhogu, Kaan; Esenoglu, Gozde; Iris, M. ErdemAdhesive joining of fiber-reinforced polymer (FRP) composites requires adequate interface tailoring and careful surface preparation to obtain a strong bond between components. This study aimed to improve the mechanical performance of adhesively bonded unidirectional carbon fiber-based (CFRP) composite parts by modifying joint surfaces with graphene-added electrospun Polyamide 6,6 (PA66) nanofibers. Reduced graphene oxide (rGO) was dispersed at 10 % wt/v PA66 solution at three different concentrations below rGO saturation limits. Bead-free nanofibers with homogenous graphene distribution were obtained on a prepreg by electrospinning. Addition of up to 2 % rGO yielded complete dispersion through the nanofiber network while the higher values created local agglomerations. Surface wetting experiments showed conversion of slightly hydrophobic surfaces to complete hydrophilic with electrospun nanofiber coating and the lowest contact angle was obtained at 2 % wt/v rGO addition (26.18 degrees +/- 2.03 degrees). Composite plates were produced in a hot press keeping the modified prepregs on top. Plates with different surface treatments joined by secondary bonding using 3 plies of FM 300 K film adhesive. Mechanical properties of adhesively bonded composites were tested by Single lap joint and Charpy impact tests. We achieved an 18 % increase in shear strength and 31 % increase in impact strength by adding 2 % wt/v ratio rGO into PA66 electrospun nanofiber.Article Citation - WoS: 63Citation - Scopus: 65Amidoxime Functionalized Polymers of Intrinsic Microporosity (pim-1) Electrospun Ultrafine Fibers for Rapid Removal of Uranyl Ions From Water(Elsevier Ltd., 2019) Satılmış, Bekir; Isık, Tuğba; Demir, Mustafa Muammer; Uyar, TamerThe Polymers of Intrinsic Microporosity (PIM-1) is considered as one of the most promising polymer candidates for adsorption applications owing to its high surface area and the ability to tailor the functionality for the targeted species. This study reports a facile method for the preparation of amidoxime functionalized PIM-1 fibrous membrane (AF-PIM-FM) by electrospinning technique and its practical use for the extraction of U(VI) ions from aqueous systems via column sorption under continuous flow. Fibrous membrane form of amidoxime functionalized PIM-1 (AF-PIM-FM) was prepared by electrospinning method owing to its excellent processability in dimethylformamide. Bead-free and uniform fibers were obtained as confirmed by SEM imaging and average fiber diameter was 1.69 +/- 0.34 mu m for AF-PIM-FM. In addition, electrospun PIM-1 fibrous membrane (PIM-FM) was prepared as a control group. Structural and thermal characterization of powder and membrane forms of the materials were performed using FT-IR, H-1 NMR, XPS, Elemental analyses, TGA, and DSC. The porosity of the samples was measured by N-2 sorption isotherms confirming amidoxime PIM-1 still maintain their porosity after functionalization. Amidoxime functionality along with membrane structure makes AF-PIM-FM a promising material for uranyl adsorption. First, a comparison between powder and membrane form of amidoxime functionalized PIM-1 was investigated using batch adsorption process. Although membrane form has shown slightly lower adsorption performance in the batch adsorption process, the advantage of using the membrane in column adsorption processes makes membrane form more feasible for real applications. In addition, amidoxime modification enhanced the uranium adsorption ability of PIM-FM up to 20 times. The effect of initial concentration and pH were investigated along with regeneration of the adsorbents. AF-PIM-FM was successfully used for five adsorption-desorption cycles without having any damage on the fibrous structure.Article Citation - WoS: 31Citation - Scopus: 34Dual Remediation of Waste Waters From Methylene Blue and Chromium (vi) Using Thermally Induced Zno Nanofibers(Elsevier, 2020) Elhousseini, Mohamed Hilal; Isık, Tuğba; Kap, Özlem; Verpoort, Francis; Horzum, NesrinElectrospun zinc oxide (ZnO) nanofibers have been significantly improved via a simple heat treatment modification. The present work reports an intriguing cost-effective microstructure tuning, by drastically dropping the temperature of the calcined sample during the cooling period, to get highly photocatalytically active ZnO nanofibers. The calcination temperatures are deducted from thermogravimetric analysis, the phase and purity are confirmed by X-ray diffraction, while the morphology and texture have been revealed by field emission scanning electron microscopy and high-resolution transmission electron spectroscopy. X-ray photoelectron spectroscopy was conducted to get further insight on the surface composition and oxidation states, while N-2-adsorption isotherms were analyzed using the Brunauer-Emmet-Teller methodology. The crystallinity, surface area, and porosity of the ZnO nanofibers, as well as the exposure of active sites, have been enhanced by the rapid cooling method. Photodegradation activity toward methylene blue was improved from 88% to 94%, and 85% to 97%, for free cooled and rapid cooled samples calcined at 300 degrees C and 500 degrees C respectively. The adsorption of chromium (VI) was also tested and reached around 85 mg/g at 100 ppm without being saturated, thereby highlighting one of the most cost-effective performance-enhancing modifications so far that could be extended on different metal oxide nanomaterials.Other Macromol. Mater. Eng. 7/2016(Wiley, 2016) Isık, Tuğba; Horzum Polat, Nesrin; Yıldız, Ümit Hakan; Liedberg, Bo; Demir, Mustafa MuammerAn easy-to-use test platform toward the rapid diagnosis of many life-threating diseases was developed. DNA was isolated from the mixture of BSA+DNA using fibrous commodity polystyrene, which was extremely cheap and can be readily electrospun under ambient conditions. Surface modification with Au nanoparticles improved the performance of the fibrous membrane.Article Citation - WoS: 45Citation - Scopus: 46Electrospun Polystyrene Fibers Knitted Around Imprinted Acrylate Microspheres as Sorbent for Paraben Derivatives(Elsevier, 2018) Demirkurt, Merve; Ölçer, Yekta Arya; Demir, Mustafa Muammer; Eroğlu, Ahmet EroğluParabens are used as antimicrobial preservatives in food, cosmetic products and pharmaceuticals regardless of their endocrine disrupting effect. In this study, highly selective molecular imprinted polymers (MIPs) were synthesized in submicron-sizes and converted to an SPME fiber coating through electrospinning process in order to determine parabens in water samples. Conversion of MIP to a fiber is achieved via creation of spacial knitting around MIP by polystyrene. The selectivity and extraction ability of the fibers were compared with the commercial fibers and the corresponding non-imprinted polymer (NIP) coated fiber. The coated fiber showed better extraction ability among them. Also, the results revealed that the fiber has better selectivity for benzyl paraben and the other structurally-related compounds, such as methyl and propyl paraben. Extraction efficiency of prepared fibers for three parabens has been tested by spiking bottled, tap and sea water samples. The recoveries changed between 92.2 ± 0.8 and 99.8 ± 0.1 for three different water types. This method could be used for selective and sensitive determination of parabens in aqueous samples.Article Citation - WoS: 6Citation - Scopus: 7Utilization of Electrospun Polystyrene Membranes as a Preliminary Step for Rapid Diagnosis(John Wiley and Sons Inc., 2016) Işık, Tuğba; Horzum, Nesrin; Yıldız, Ümit Hakan; Liedberg, Bo; Demir, Mustafa MuammerRecent advances in clinical practice drive deoxyribonucleic acid (DNA) as an important class of biomarker. Monitoring the change in their concentration suggests the initiation and/or progression of various disorders. However, low quantity of DNA biomarkers in body fluids requires a delicate isolation methodology that provides efficient separation and easy handling. This study describes a newer-generation separation technology relying on electrospun fibers of sub-micrometer diameter of a commodity polymer for DNA biomarkers in simulative serum. Fibrous polystyrene membranes are prepared by electrospinning and they are subjected to post-modification with Au. The composite membranes may provide a convenient environment for the removal of bovine serum albumin (BSA) from BSA and DNA mixtures. The eluent can be used as an efficient tool for detection of DNA biomarkers associated with diagnosis of numerous life-threatening diseases.Article Citation - WoS: 109Citation - Scopus: 119Synthesis of Amidoximated Polyacrylonitrile Fibers and Its Application for Sorption of Aqueous Uranyl Ions Under Continuous Flow(Elsevier Ltd., 2012) Horzum Polat, Nesrin; Shahwan, Talal; Parlak, Onur; Demir, Mustafa MuammerThis study reports a feasible method for the removal of radioactive U(VI) ions from aqueous systems via column sorption under continuous flow. Electrospun polyacrylonitrile (PAN) fibers were used as sorbent materials in a homemade minicolumn. The nitrile groups on the fibers' surface were modified to amidoxime groups using hydroxylamine hydrochloride. Surface modification was observed to enhance the sorption capacity of PAN fibers toward uranium ions by more than 4-fold by virtue of the chelating ability of the amidoxime groups. The experiments investigated the effect of pH, initial concentration, and repetitive loading on the sorption properties of amidoximated PAN fibers. Based on the overall results, the surface-modified fibers seem to be a suitable potential sorbent material for applications in environmental cleanup, particularly for nuclear plants.Article Citation - WoS: 64Citation - Scopus: 67Hierarchically Structured Metal Oxide/Silica Nanofibers by Colloid Electrospinning(American Chemical Society, 2012) Horzum Polat, Nesrin; Mun˜oz-Espí, Rafael; Glasser, Gunnar; Demir, Mustafa Muammer; Landfester, Katharina; Crespy, DanielWe present herein a new concept for the preparation of nanofibrous metal oxides based on the simultaneous electrospinning of metal oxide precursors and silica nanoparticles. Precursor fibers are prepared by electrospinning silica nanoparticles (20 nm in diameter) dispersed in an aqueous solution of poly(acrylic acid) and metal salts. Upon calcination in air, the poly(acrylic acid) matrix is removed, the silica nanoparticles are cemented, and nanocrystalline metal oxide particles of 4-14 nm are nucleated at the surface of the silica nanoparticles. The obtained continuous silica fibers act as a structural framework for metal oxide nanoparticles and show improved mechanical integrity compared to the neat metal oxide fibers. The hierarchically nanostructured materials are promising for catalysis applications, as demonstrated by the successful degradation of a model dye in the presence of the fibers.