Browsing by Author "Kocum, I. Cengiz"

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    Aligned Polyvinylpyrrolidone Nanofibers with Advanced Electrospinning for Biomedical Applications
    (2018) Karayegen, Gokay; Kocum, I. Cengiz; Serdaroglu, Dilek Cokeliler; Dogan, Mustafa; 0000-0001-5215-8887; 30400080; I-4296-2019
    BACKGROUND: Electrospinning is a highly effective method in order to generate nano-scaled fibers. In conventional electrospinning technique, geometry of nanofibers are mostly random due to the chaotic behavior of polymer jet. OBJECTIVE: Purpose of this study is to produce aligned nanofibers from PVP polymers with advanced electrospinning technique in order to be used in a potential novel sensor applications, tissue regeneration and engineering. METHODS: In this study, by using finite hollow cylinder focusing electrodes, an external electrostatic field is created. With these electrodes, it is aimed to decrease whipping instability of polymer jet. In addition, it is also investigated that the alignment ratio of nanofibers by using conductive parallel electrodes which placed through jet trajectory. RESULTS: In conclusion, with the effect of electrical field created by cylinder electrodes, radius of the fiber dispersion on the collector was able to be reduced and aligned nanofibers were successfully produced by using electrical field generated from the parallel plates. CONCLUSIONS: Radius of the fiber dispersion on the collector is 9.95 mm and fiber diameters varied between 800 nm and 3 mu m. Additionally, alignment ratio of the fibers is determined with ImageJ software. These alignment of nanofibers can be used in tissue engineering applications and sensor applications.
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    Stepwise implementation of a low-cost and portable radiofrequency hyperthermia system for in vitro/in vivo cancer studies
    (2021) Senturk, Fatih; Kocum, I. Cengiz; Ozturk, Goknur Guler
    In recent years, interactions of radiofrequency (RF) electromagnetic fields with biological tissue have become one of the most promising strategies for noninvasive cancer hyperthermia treatment. Despite the growing interest, there has been a scarcity of studies involving the detailed construction of a complete RF-hyperthermia (RF-HT) system. Here a low-cost and high-power RF-HT system is reported with a specific frequency which can be used in biological samples. A laboratory-constructed RF-HT system composed of a radiofrequency oscillator, radiofrequency driver, radiofrequency amplifier, radiofrequency matching network, and an induction coil applicator were constructed and characterized by a stepwise approach. Although the RF driver and amplifier were purchased as professionally designed kits, significant modifications were required for these components. The results showed that the RF-HT system was successfully constructed and tested at 13.56 MHz with a power as high as 400 W. As a preliminary biological experiment, cell culture medium exhibited an approximate 3 degrees C increase in temperature induced by the RF-HT device at 250 W for 10 min. Moreover, the developed system is suitable drug targeting, drug release, and cellular uptake and designed to be cost-effective for in vitro/in vivo studies involving cancer therapy.