Fakülteler / Faculties
Permanent URI for this communityhttps://hdl.handle.net/11727/1395
Browse
10 results
Search Results
Item An Alternative Electrospinning Approach With Varying Electric Field for 2-D-Aligned Nanofibers(2014) Karatay, Okan; Dogan, Mustafa; Uyar, Tansel; Cokeliler, Dilek; Kocum, Ismail Cengiz; U-7861-2018In the electrospinning process, unstructured nanofiber mats are produced by oriented fluid jets with an external electrostatic field. Electrospun fibers have wide applications for the fabrication of composite materials, tissue scaffold, and membranes. However, electrospun fiber production systems have many problems, e. g., the bending instability due to the complicated oscillations of polymer jet. In this research, parallel plate and hollow cylindrical conducting electrodes are implemented through the jet trajectory in order to investigate the possibility of controlled deposition of polymer fibers. Parallel electrodes with proper driving sources can generate the steering field for the nanofiber formation at the collector plate based on analog addressing electronics. It was shown that the modulated electric field applied through the parallel plate electrodes notably increased the deposition of the electrospun polymer fibers in a controlled fashion at the collector, which is coherent to the computer simulations. Furthermore, the finite-length hollow cylinder dampened the bending instabilities of the polymer jet which decreases the characteristic spot size of the deposited electrospun fiber to a smaller diameter.Item GRGDS-Conjugated and Curcumin-Loaded Magnetic Polymeric Nanoparticles for The Hyperthermia Treatment of Glioblastoma Cells(2021) Senturk, Fatih; Cakmak, Soner; Kocum, Ismail Cengiz; Gumusderelioglu, Menemse; Ozturk, Goknur GulerThermally responsive and ligand-mediated drug delivery systems have the potential to improve the treatment of brain tumors, especially, most lethal one, glioblastoma multiform (GBM). Magnetic nanoparticle-mediated hyperthermia becomes one of the most promising alternative therapy for GBM treatment in cases where localized heating and targeted delivery of a therapeutic drug can be achieved on the tumor site. In this study, it is aimed to increase the therapeutic efficiency of multi-functionalized nanoparticles (NPs) in combination with radiofrequency hyperthermia (RF-HT) on GBM cells. For this purpose, firstly, a low-cost and portable home-built RFHT system suitable for in vitro/in vivo studies was successfully implemented and tested at 13.56 MHz frequency with power up to approximately 400 W. Subsequently, the highly monodispersed superparamagnetic iron oxide nanoparticles (SPIONs), which could interact with the RF magnetic field, were synthesized with the mean particle size of 5.6 +/- 0.9 nm. The obtained SPIONs were coated with poly (lactic-co-glycolic acid)-poly (ethylene glycol) di-block copolymer (PLGA-b-PEG). Most of the SPIONs were uniformly distributed in such a well-defined spherical-shaped polymeric NP. Moreover, curcumin (Cur), a potential agent for GBM treatment, was loaded into the magnetic polymeric nanoparticles (m-PNPs) with a loading capacity of 8% (w/w, Cur/NPs) and a mean diameter of Cur-loaded m-PNPs (Cur-m-PNPs) was 142 +/- 70 nm. To increase cellular uptake and targeting ability of NPs, glycine-arginine-glycine-aspartic acid-serine (GRGDS) peptide was immobilized on the Cur-m-PNPs and the amount of GRGDS was detected as 37 mu g/mg NPs. In vitro cytotoxicity studies revealed that the presence of GRGDS on Cur-m-PNPs (GRGDS-Cur-m-PNPs) improved the cytotoxic efficiency of Cur-m-PNPs by 6-fold in GBM-cells for all incubation times (24, 48 and 72 h). Furthermore, NPs with RF treatment exhibited higher antitumor activity than that of NPs without RF on GBM cells. This result may be attributed to the thermal (SPIONs) or non thermal (cellular membrane) effects or both of them on cells. Overall, this study showed that RF-HT in combination with GRGDS-Cur-m-PNPs could provide a feasible approach to improve GBM treatment.Item Electrospun Nanofiber Reinforcement of Dental Composites with Electromagnetic Alignment Approach(2016) Uyar, Tansel; Cokeliler, Dilek; Dugan, Mustafa; Kocum, Ismail Cengiz; Karatay, Okan; Denkbas, Emir Baki; https://orcid.org/0000-0001-5215-8887; 26952482; U-7861-2018; I-4296-2019Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling, however, when it is used in prosthetic dentistry, fracturing or cracking problems can be seen due to the relatively low strength issues. Besides, acrylic resin is the still prominent material for denture fabrication due to its handy and low cost features. Numerous proposed fillers that are used to produce PMMA composites, however electrospun polyvinylalcohol (PVA) nanofiber fillers for production of PMMA composite resins are not studied as much as the others. The other focus of the practice is to compare both mechanical properties and efficiency of aligned fibers versus non-aligned PVA nanofibers in PMMA based dental composites. Field controlled electrospinning system is manufactured and provided good alignment in lab scale as one of contributions. Some novel auxiliary electrodes in controlled structure are augmented to obtain different patterns of alignment with a certain range of fiber diameters. Scanning electron microscopy is used for physical characterization to determine the range of fiber diameters. Non-woven fiber has no unique pattern due to chaotic nature of electrospinning process, but aligned fibers have round pattern or crossed lines. These produced fibers are structured as layer-by-layer form with different features, and these features are used in producing PMMA dental composites with different volume ratios. The maximum flexural strength figure shows that fiber load by weight of 0.25% w/w and above improves in the maximum level. As a result, mechanical properties of PMMA dental composites are improved by using PVA nanofibers as a filler, however the improvement was higher when aligned PVA nanofibers are used. The maximum values were 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), and 170 kJ/m(3) (toughness) in three-point bending test. In addition to the positive results of aligned and nonaligned nanofibers it was found that they both have a non-toxic feature. (C) 2016 Elsevier B.V. All rights reserved.Item Configuration of Hardware for Medical Plasma Based Surgical Device and Features(2018) Recber, Deniz; Kayserilioglu, Batuhan; Kocum, Ismail Cengiz; Cokeliler Serdaroglu, DilekThis research, covers the evaluation of the performance of harware of plasma-based (gas plasma, plasma jet) surgical prototype device which will be used in microsurgery, identification of active device operating conditions with the appropriate engineering models Microsurgery is by taking advantage of the magnifying effect of the special operation microscope, very small structures that can hardly be seen with the naked eye and surgery using very thin instrument. It is necessary to emphasize, the plasma technique using on directly liver cell for the treatment is the novel study. The examples of portable commercial devices in the world have started to increase in the recent past, but they are still few. The project has three main design in general; primarily high voltage power supply, bipolar plasma probe, gas supply control unit made it. High voltage power supply made with transformator and mosfets connecting with push-pull. Bipolar plasma probe, made 2 tungsten rod which mounted on the board mechanism and used teflon wire for connection with high voltage power supply. For the gas supply control unit, used microprocessor controlled and transistor amplifier selenoid valve. Thus, it is aimed to trigger the solenoid valve and adjust the gas flow in the adjustable frequency range. In the first tests made, the formation of radiation of the high voltage circuit was observed. The integration with the tungsten probe system was completed and tried to test the relation between angle and distance and radiation. In addition, the completed parts of the gas supply control unit designed together with the solenoid valve and the microprocessor have been tested. etc.] in its style sheet. As a result, the distance parameter of radiation formation is determined by high voltage circuit tests. Radiation-angle tests were performed and later turned into a prototype with the outer design of the device.Item Design and Construction of Affordable and Domestic Device for Carbon Nanoparticle Synthesis(2018) Aykutlu, Dilara; Okursoy, Berkay; Kocum, Ismail Cengiz; Cokeliler Serdaroglu, DilekNanoparticles are structures below 100 nanometer and used for molecular imaging with gene therapy, implementation of many biomedical applications such as biosensor, cancer-pathology diagnosis and treatment, targeted drug-making and therefore superior in application areas. The aim of the study is to develop a device that synthesizes carbon nanoparticles by dense medium plasma method; together with hardware, software and mechanical design. Dense medium plasma is an easy synthesis approach with low cost; However, it is necessary for the user of this device to be more comfortable to use, feasible, portable and suitable for market. Moreover there is no commercial device for synthesing carbon nanoparticles by dense medium plasma technique. This research presents details of construction of affordable device for carbon nanoparticle sythesis. Prototype is an unique domestic product and contains integrated hardware, software and mechanical probe parts. Hardware part consists of control, power unit and induction coil unit and these three units are connected to each other. The power unit ensures that the mosfets are triggered by a certain voltage from the control unit. The induction coil unit is induced by turning the low voltage to high voltage. In the mechanical part, probe design supplies discharge betweeen electodes which are fed by argon gase that converts benzene to the carbon nanoparticles. The probe reaches the resonance frequency and to make it easier to adjust the distance between the bottom and top electrode, a spindle system is used. Software operation is measuring high voltage. To make the appliance portable, moreover wheeled table production was done. As a result, signal and power card tests were made, it was observed that the high voltage circuit, the signal circuit and the induction coil cause radiation. More nanoparticle production was achieved with the controllable distance between the bottom electrode and the top electrode of probe. The efficiency of the synthesis was improved and the usage of the device was made practical. Finally prototype device that is usable for synthesis nanoparticles by dense medium technology is constructed affordablity and presented with all details.Item Novel Concept On In Situ Syntheses And Investigation Of Photon Energy Effect On Agnp Size With A Custom Build Device For Enhanced Antimicrobial Efficiency(2022) Bunyatova, Ulviye; Kocum, Ismail Cengiz; Turkmen, Kubra Erkan; Haberal, Orhan Erdem; Kocak, Onur; Koca, Helin Cikmaz; 10.1007/s11051-022-05612-2The objectives of the present study were to examine the influence of visible light photons on photoreduction of the silver nanoparticles (AgNPs), detect optoelectronic feedback, and observe the antimicrobial activity. For this purpose, an optoelectronic device was designed and successfully tested. The finding shows that identical nanocomplexes with silver salt express various responses to the LEDs with different wavelengths by scattering different portions of light. It is the first time to discuss the effect of visible light photons on nanosized particles in detail based on the quantitative optical/voltage analysis. The photoreduction of the AgNPs is in good agreement with photon energy and the AgNPs occur in nanocomplex in a wavelength versus time-dependent mariner. The blue LED having photon energy 7.04 eV reduces the average size of AgNPs down to the range 4-6 nm in 12 min, while AgNPs obtained under influence of green (6.11 eV) and red (5.04 eV) LEDs have average sizes 6-8 nm and 12-14 nm respectively. The successful synthesis of AgNPs was additionally examined using UV-Vis, SEM, XPS, XRD, FTIR, and TEM techniques. AgNPs proved for antimicrobial activity against Escherichia coli 25922, Enterococcus faecalis 29212, Pseudomonas aeruginosa 27853, and Candida albicans 10231 at four different concentrations. The antibacterial test for all selected bacteria showed that AgNPs which have an average size of 4-6 nm synthesized by blue LED revealed the largest inhibition zone around 16-11 mm, while the antifungal test shows that the maximum inhibition zone was exposed by AgNPs which have an average size of 6-8 nm synthesized by red LED.Item Effects of radiofrequency exposure on in vitro blood-brain barrier permeability in the presence of magnetic nanoparticles(2022) Senturk, Fatih; Cakmak, Soner; Kocum, Ismail Cengiz; Gumusderelioglu, Menemse; Ozturk, Goknur Guler; 35134610The blood-brain barrier (BBB) remains a major obstacle for the delivery of drugs in the treatment of many neurological diseases. In this study, we aimed to investigate the effects of radiofrequency electromagnetic fields (RF-EMFs) on the permeability of an in vitro BBB model under RF exposure alone, or in the presence of nanoparticles (NPs). For this purpose, an in vitro BBB model was established by seeding human umbilical vein endothelial cells (HUVECs) and human glioblastoma cell line (T98G) on the apical and basolateral sides of the transwell membrane, respectively. The integrity of the BBB model was confirmed by measuring transendothelial electrical resistance (TEER), and a fluorescein isothiocyanate (FITC)-dextran permeability assay was performed when the resistance reached 120 U cm(2). After the RFfield exposure (13.56 MHz, 80 W, 10 min), we found that FITC-dextran transported across the in vitro BBB was increased 10-fold compared to FITC-dextran transported without an RF-field. This notable phenomenon, which can be called the burst permeability RF effect (BP-RF), has been proposed for the first time in the literature. Subsequently, the effect of the RF-field on BBB permeability was also investigated in the presence of superparamagnetic iron oxide nanoparticles (SPIONs) and magnetic poly(lactic-co-glycolic acid)-polyethylene glycol (PLGA-b-PEG) nanoparticles (m-PNPs). It was found that the amount of both transported NPs on the basolateral sides increased after exposure to the RF-field. As a result, the RFfield can be applied simultaneously during treatment with clinical agents or nanocarriers, improving the permeability of the BBB, which may contribute to therapeutic efficacy of many drugs that are used in neurological diseases. (c) 2022 Elsevier Inc. All rights reserved.Item Calibration of Quartz Tuning Fork transducer by coulometry for mass sensitive sensor studies(2019) Dedeoglu, Aylin; Karadas, Nurgul; Unal, Mehmet Altay; Kocum, Ismail Cengiz; Serdaroglu, Dilek Cokeliler; Ozkan, Sibel AysilMass-sensitive sensing has one main advantage: mass is one of the most fundamental properties of any analyte. They also require suitable recognition materials to ensure selectivity. Quartz Tuning Forks (QTFs) have been known as common oscillator components due to their stable resonant frequencies. In recent years, QTFs have started to be implemented as transducers into sensor systems which has the potential on resulting mass-sensitive sensors with high reliability. In this study, a developed QTF mass-sensitive sensor system has been utilized for applying calculations and finally formulizing the frequency to mass-load relationship for the standard 32,768 Hz QTF. Coulometric copper deposition method was used for a reliable mass-load that could be calculated consequently from the charge reduction measured through the potentiostat. Frequency changes were calculated through the measurements read on the QTF sensor system described. SEM imaging and SEM-EDX element analysis methods were used to assay and confirm the modification performed on the surface.Item Design of a portable and low-cost mass-sensitive sensor with the capability of measurements on various frequency quartz tuning forks(2019) Unal, Mehmet Altay; Kocum, Ismail Cengiz; Cokeliler Serdaroglu, Dilek; 0000-0001-8645-9047Recently, sensor and biosensor applications have become widespread and are now significant tools in the biomedical field and other areas. Since quartz tuning fork (QTF) resonance frequency depends on the mass adsorbed to its prongs, it is generally used to measure minor mass change and detect target analyte in picogram levels. This study is undertaken to design and fabricate a sensor device for the measurement of QTF transducers. When QTF sensor studies were investigated, it was found that explanations on the details of instrumentation part were limited, and in addition, there was no compact commercial products. In this study, a novel, low-cost, portable quartz tuning fork sensor device with ability to work with any kind of display is presented in detail. Moreover, the effect of the ambient temperature during the measurements was checked. Six other QTF transducer types, 32, 32.768, 40, 65.536, 75, and 100 kHz, have been studied as the other novel part of the research. As a result, a QTF sensor device was fabricated that has further advanced features when compared with its alternatives and works with a more accurate measurement method. Owing to this advancement, using biosensor/chemical sensor which consists of QTF transducers with features that can take sensitive analyte measurement in picogram level will be able to spread.Item Penetration Depth in Nanoparticles Incorporated Radiofrequency Hyperthermia into the Tissue: Comprehensive Study with Histology and Pathology Observations(2019) Nasseri, Behzad; Kocum, Ismail Cengiz; Seymen, Cemile Merve; Rebiee, Navid; 31432798In present study, the effective penetration of radiofrequency (RF) induced gold decorated iron oxide nanoparticles (GS@IONPs) hyperthermia was investigated. The effective penetration depth of RF also the damage potency of hyperthermia was evaluated during histopathology observations which were done on the chicken breast tissue and hepatocellular carcinoma (HCC) models. The thermal damages are well- documented in our previous cellular study which was engaged with potency of RF hyperthermia in Epithelial adenocarcinoma (MCF-7) and fibroblast (L-929) cells deaths [1]. In recent work, PEGylated iron oxide nanoparticles (IONPs) were used as base platform for gold magnetic nanoparticles (GS@IONPs) formation. The 144.00015 MHz, 180W RF generator was applied for stimulating the nanoparticles. The chicken breast tissue and the hepatocellular tumor model was considered in the experimental section. In histology studies, the structural changes also the effective penetration depth of RF induced nanoparticles was observed through microscopic monitoring of the tissue slices in histology observations (Gazi medical school). The highest damage level was seen in 8.0 mu m tissue slices where lower damages were seen in depth of 1.0 cm and more inside tissue. The histology observations clarified the effective penetration depth of RF waves and irreversible damages in the 2.0 cm inside the tissue.