WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article A Simplified Molecular Imprinting Strategy Through Electrospinning of Polyacrylonitrile for Thin Film Microextraction of Selected Pesticides(Elsevier B.V., 2026) Şahin, A.; Akpinar, Y.; Yildirim, E.; Eroǧlu, A.E.; Boyaci, E.Molecularly imprinted polymers (MIPs) have been extensively used as selective extractive phases for sample preparation because of their analyte-selective binding sites. However, MIP preparation requires optimized monomer-template interactions and long polymerization reactions. In this study, a novel and simple method of MIP preparation was proposed based on electrospinning. Instead of preparing analyte-monomer complexes before polymerization, model analytes (trifluralin and carbaryl) were directly dissolved in a polyacrylonitrile (PAN) solution, then electrospun into nanofibrous mats. This allowed for a means of preparation of highly crystalline, template-imprinted nanostructures with minimal synthetic complexity. Following the characterization studies for the new material, the extraction properties of the imprinted and nonimprinted electrospun mats were investigated in thin film microextraction (TFME) studies by extracting trifluralin and carbaryl from water samples, followed by gas chromatography-mass spectrometry (GC–MS) analysis. The optimization results showed that samplers containing 10.0 mg of MIP sorbents made by electrospinning of a solution containing 5.0 mg of template in 1.0 mL of PAN solution resulted in approximately 4 and 7 times enhanced extraction recoveries for carbaryl and trifluralin compared to samplers made of non-imprinted bulk PAN. Moreover, the cross-reactivity testing performed with non-template analytes (malathion and diazinon) suggested a more specific extraction towards trifluralin compared to carbaryl. The proposed new technique was also validated using computational methodology, which supported the experimental finding about higher selectivity towards trifluralin. This may signify a probability for structural orientation of partially charged trifluralin under an electrical field in electrospun PAN creating favorable extraction sites. © 2025 Elsevier B.V.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: 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.