Browsing by Author "Serdaroglu, Dilek Cokeliler"

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A Plasma Arc-Based Electromechanical System Designed for Microchannel Processing
(Başkent Üniversitesi Mühendislik Fakültesi, 2024-05-31) Akin, Fevzi; Ersoy, Ece; Idil, Deniz; Ozsimitci, Melih; Serdaroglu, Dilek Cokeliler; Ic, Yusuf Tansel; Atalay, Kumru Didem; Kocum, Cengiz; Okat, Kemal
Plasma technology is based on a simple physical principle. When more energy enters the gas, it ionizes and becomes the fourth state of matter, the energy-dense plasma. The studies carried out within the scope of this study were designed to create microchannels on lamellar glass using an improved redesign of the current plasma arc device, which is the main subject of the paper. The created microchannel is examined at the microscale. Experimental analysis was conducted considering the effect of plasma on the effect of microchannel quality. We performed an experimental design study to determine the optimal parameter levels for improving microchannel quality. The predicted results have been validated with the experimental results. An experimental design study provides useful results, such as information about the distance between the probes, pulse duration, and material temperature, which enhances the channel dimensions. The improved device can be utilized effectively to establish microchannel processing in practice.
Accelerating The Environmental Biodegradation Of Poly-3-Hydroxybutyrate (Phb) Via Plasma Surface Treatment
(BIORESOURCE TECHNOLOGY REPORTS, 2024-09-02) Akdogan, Ebru; Sirin, Hasret Tolga; Sahal, Gulcan; Deniz, Zulkuf; Kaya, Ayberk; Serdaroglu, Dilek Cokeliler
The surface of poly-3-hydroxybutyrate (PHB) was modified using a low-pressure plasma system with air as the process gas to accelerate its biodegradation rate in soil. The water contact angle of PHB was reduced from 98 degrees to 57 degrees after plasma treatment, rendering the surface hydrophilic and also induced an increase in the surface free energy. Etching on the surface was observed after the plasma treatment without a significant change in the surface crystallinity. AFM imaging showed that the plasma treatment increased the surface roughness by about 10 folds and created diverse surface structures. The soil burial test showed an approximately 1.5-fold increase in the biodegradation rate for the plasma-treated sample. Initial microbial attachment and biofilm formation were higher on the modified surface. This study demonstrated that the surface morphology created by plasma treatment promoted initial colonization and subsequent biofilm formation on the PHB surface, facilitating and accelerating its biodegradation in soil.
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.
Antibody Immobilization Techniques in Mass Sensitive Immunosensor: Enhanced Sensitivity through Limited Mass Load
(2022) Kirali, Kubra; Brimo, Nura; Serdaroglu, Dilek Cokeliler; https://orcid.org/0000-0002-3053-2169; https://orcid.org/0000-0002-9604-263X; https://orcid.org/0000-0001-8645-9047
Background: Biosensors are analytical devices that include a sample-delivery approach between a biological recognition element and a transducer required to convert the physicochemical change produced from the interaction of biological molecule-receptor interaction into a signal. The immunosensor is a special type of biosensor that includes an antibody as a biorecognition element to detect analytes as antigens. In mass sensitive sensors, antigen-antibody interactions can be specified by measuring the frequency change and the most commonly knowns are the surface acoustic wave, bulk acoustic wave, quartz crystal microbalance and microcantilevers. Methods: Different methods for antibody immobilization, including functionalization of the transducer surface with specific groups, have been reported for antibody immobilization. This stage affects the limit of detection and overall performance. In this review, perspectives on immobilization strategies of mass sensitive immunosensors according to transducer types will be presented. The choice of immobilization methods and their impact on performance in terms of capture molecule loading, orientation and signal improvement will also be discussed. Results: One of the most critical points during the configuration of the biorecognition layer is to improve the sensitivity. Therefore, we initially focused on comparisons of the antibody immobilization strategies in the biorecognition layer in terms of mass load level and high sensitivity. Conclusion: The lack of significant data on the mass accumulations up to the functionalization and antibody immobilization steps, which are the basis of immusensor production, has been identified. However, mass sensitive immunosensors have the potential to become more common and effective analytical devices for many application areas.
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 Aysil
Mass-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.
Comparing Antibiotic Pastes with Electrospun Nanofibers as Modern Drug Delivery Systems for Regenerative Endodontics
(2022) Brimo, Nura; Serdaroglu, Dilek Cokeliler; Uysal, Busra; https://orcid.org/0000-0002-9604-263X; https://orcid.org/0000-0001-8645-9047; 000847330300002
Nanomaterials can be applied in different biomedical applications like diagnosis, treatment, and drug delivery due to their unique features. Using such materials in the endodontic treatment processes may prove challenging as these materials must exhibit antibacterial effects without posing any harm to the host cells. The approach involving nanofibers loaded with various antibacterial drugs offers a potential treatment method to enhance the elimination procedure of intracanal biofilms. Clinically, many models of bacterial biofilms were prepared under in vitro conditions for different aims. The process of drug delivery from polymeric nanofibers is based on the principle that the releasing ratio of drug molecules increases due to the increase in the surface area of the hosted structure. Our review discusses diverse approaches to loading/releasing drugs on/from nanofibers; we summarized many studies on electrospun nanofibers loaded with various drugs applied in the endodontic field. Moreover, we discussed both the advantages and the limitations of these modern endodontic treatment materials, comparing them with the traditional ones.
Improving The Quality Of Micro Holes Drilled With A Current Detection Plasma Arc Device
(JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING, 2024-10) Ic, Yusuf Tansel; Kocum, Cengiz; Atalay, Kumru Didem; Serdaroglu, Dilek Cokeliler; Akar, Gurel; Polat, Isil Yanki; Samsun, Berk; Caliskan, Sevde; Atmaca, Dicle Naz; Karayalcin, Serkan
Today, microholes play a crucial role in many sectors. Microholes are used in fields such as aerospace, computer systems, and electronic and mechanical industries. In this paper, we improve the performance of the current sensing plasma arc device to create holes within the same diameter, appropriate delamination, and surface quality. In addition, we aim to improve the processing quality of the current sensing plasma arc device, which drills holes from the micron level to the millimeter level and creates microstructures on hard, durable, and inert materials such as glass and quartz. Additionally, we presented a multiobjective optimization model to reach the optimal factor levels to obtain the minimum hole diameter with minimum delamination. For this objective, we propose a design of an experiment-integrated goal programming model in this study. The optimal levels are 90 Watt, 18 Hz, 2.73 ms, and 11.6 cm for the parameter values Power, Frequency, Lead time, and Distance between the probes, respectively, to reach the optimal diameter (183 mu m) and delamination values (1.025).
Nanoparticle Embedded Nanofiber Synthesis and Evaluation of Usability on Biomedical Applications
(2018) Serdaroglu, Dilek Cokeliler; Korkusuz, Hilal K.; Karakaya, Mine; Donmez, Ilknur; Unal, Mehmet A.; Gunasekaran, Sundaram; 0000-0001-8607-5043; 0000-0001-6553-1273; GWU-9030-2022; AAD-2194-2019; AAQ-2457-2021
When nalloparticks and nanofibers combined at the na oscrth, they could eremite new features in the material and therefore new areas of use. In this study, polyvinylpwroliclone (PM nanofibers containing Carbon nanoparticles produced by dense medium plasma technology have been fabricated via electro.spinning technique for the first time, a new class ofnanocomposite mat material has been prepared and wythatted jthr medical devices. A dense medium plasma technique is used far nallopcslicles sytithesis, which is P2OVel, COSI-effielePg, and fast techtiolo git when is compared with other common nanopthticles synthesis techniques. Carbon based nanoparticles are synthesized from an arc sustained in benzene (purity, 99.590 between iron electrodes by the lab madedense medium plasma systenl. The study first mentions the pl'OChIction of nanoparticles by a pressure tif8 bar argon gas for glow discharge in a period of 9 seconds using a 0.5 in electrode distance in a liquid environment huMume of benzene: 30 inti Then, separated carbon nanoparticles are integrated with the Picid nanqfiben' prOduCed by the electrospinning method Processing parameters of P1P nanofibers containittg carbon nefflopartic C (hanocompthites) are optimized with)thrious conditions such as polymer concentration: 7.8-8.0 %w/v, /Chic ofnuanoparticic to polymer solution: 1-3.9 mg ml, distance of electrode: 10-25 cm, processing time: 5-30 min-411 Samples are charaCterized by contact angle measurements, scanning electron microscopy and transmission electron microscopy. At the same time, electrical conductivity of nanocomposite mats are tested for foreseeing usage in biomedical application. Results showed that carbon nttnopeattic les have diameters in 25 iL 5.4 Pun. New nefilOCOmposite matericdproduction is proven by, transmission electron microscopy. It is a super hydrophilic mat material ("static contact angle is lower than 10l). According to the optimization of processing parameters, the diameters of iumthcomposite fibers reach down to 150 +/-75 tan., tVanocomposite mat resistance is,found to be dramatically higher than that,for the bare PIT nanofiber mat resistance. According to these rendth usage in biomedical applicanon of new mcdericd w is diSCUSSed It has a great potential to use as biocompitible, light, insulator new material.