Bioengineering / Biyomühendislik
Permanent URI for this collectionhttps://hdl.handle.net/11147/4529
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Conference Paper 3d Printing-Assisted Fabrication of Microfluidic Pneumatic Valves(IEEE, 2023) Keleş, Şeyda; Karakuzu, Betül; Tekin, Hüseyin CumhurPneumatic valves have a crucial place in the fluidic control in microfluidic systems. Pneumatic valves containing polydimethylsiloxane (PDMS) membrane structures are used in microfluidic systems such as cell separation, and cell manipulation due to their flexible structure, and ease of production. This study demonstrates the rapid and straightforward fabrication of pneumatic valve structures using PDMS membranes, achieved through the utilization of 3D-printed molds. As a result of our experiments, we observed valve closure in a fluidic channel with a height of 150 μm. This closure was achieved by utilizing 400 μm × 800 μm PDMS membrane with a thickness of 66 μm positioned between the fluidic and control channels, while applying 1.5 bar of pressure to the control channel. When the pressure is removed, the opening time of the valve is only 0.02 s, and this response time allows rapid valving function. The presented valve fabrication strategy would allow easy and low-cost production of sophisticated microfluidic chips. © 2023 IEEE.Conference Object Lots and Loop-Mediated Isothermal Amplification-Based Biosensing Using Cloud-Enabled Features(IEEE, 2022) Bayındır, Taha; Değirmenci, Mehmet; Ergenç, Ali Fuat; Elitaş, MeltemInternet-of-Things technology (IoTs) have accelerated biosensor applications in all fields. Loop-mediated isothermal amplification (LAMP)-based biosensor technologies in conjunction with smartphone detection have been adequate to cover the demands of mobile diagnostics. The ease of use, affordability, portability, high sensitivity, flexibility, and specificity demands of point-of-care detection can be achieved by low-cost electronic components, 3-dimensional printing technologies, capturing images of calorimetrically detected readouts made our system a promising approach for real-time point-of-detection in the field. In this study, we implemented a cloud service to our LAMP-based biosensor. We previously performed bacteria detection using colony-based LAMP device and now distributed the optical readouts of the assay using smartphones. We transferred the obtained image and results of the assays through cloud. Our user-friendly interface simplifies the data processing, it directly digitized the readouts and eliminates the need of data interpretation.Conference Object Detection and Restoration Pipeline for Phase Contrast Microscopy Time Series Images(IEEE, 2022) Iheme, Leonardo O.; Uçar, Mahmut; Önal, Sevgi; Yalçın Özuysal, Özden; Pesen Okvur, Devrim; Töreyin, Behçet U.; Ünay, DevrimWe propose a pre-processing pipeline for the de-tection and restoration of distorted frames in phase-contrast microscopy time-series images. The analysis is based on the average intensity values of the frames within any given time- series image. The extent of the correction of intensity variation in frames is determined by the normalization of the difference between the current frame's average intensity and the median of average intensity of all frames. Our restoration algorithm preserves regional trans-passing pixels, does not cause new distortions, and increases the histogram similarity between the distorted and non-distorted frames. The algorithm was validated on 15,395 time-series image frames from 27 experiments and the results were found to be visually and quantitatively accurate.Conference Object Citation - Scopus: 1Magnetic Levitation-Based Adipose Tissue Engineering Using Horizontal Magnet Deployment(IEEE, 2020) Sarıgil, Öykü; Tekin, Hüseyin Cumhur; Anıl İnevi, Müge; Anıl İnevi, Müge; Yılmaz, Esra; Sarıgil, Öykü; Özçelik, Özge; Meşe Özçivici, Gülistan; Meşe, Gülistan; Meşe Özçivici, Gülistan; Tekin, H. CumhurMagnetic levitation is a promising technique for tissue engineering with contact- and label-free approach. Levitation-based biofabrication systems emerge as a simple, rapid and versatile alternative to traditional tissue culture systems, since biofabrication specs can easily be tailored via magnet shape and configuration. This study aims at possible magnetic levitation systems for culture of adipose tissue cells. In this study, we performed two different magnet configurations, vertical and horizontal deployment, in an effort to be utilized in adipose tissue engineering.Conference Object Assessment of Cell Cycle and Viability of Magnetic Levitation Assembled Cellular Structures(IEEE, 2020) Anıl İnevi, Müge; Ünal, Yağmur Ceren; Yaman, Sena; Tekin, H. Cumhur; Meşe, Gülistan; Meşe, GülistanLabel-free magnetic levitation is one of the most recent Earth-based in vitro techniques that simulate the microgravity. This technique offers a great opportunity to biofabricate scaffold-free 3-dimensional (3D) structures and to study the effects of microgravity on these structures. In this study, self-assembled 3D living structures were fabricated in a paramagnetic medium by magnetic levitation technique and effects of the technique on cellular health was assessed. This magnetic force-assisted assembly system applied here offers broad applications in several fields, such as space biotechnology and bottom-up tissue engineering.Conference Object Citation - WoS: 12Citation - Scopus: 17Wearable Respiratory Rate Sensor Technology for Diagnosis of Sleep Apnea(IEEE, 2020) Cinel, Göktürk; Tarım, Ergün Alperay; Tekin, Hüseyin CumhurSleep apnea is a disease that occurs during sleep, which affects the daily life of patients due to the obstruction of the upper respiratory tract and decreases oxygen level in blood and it may even lead to patient death in the later stage. Monitoring the patients regularly has absolute importance to prevent patient disorders caused by sleep apnea. Wearable sensor technologies and patient tracking systems provide diagnosis, treatment, and monitoring of patients, and procure better health services in medical fields. In addition to decreasing the workload of health institutions, remote patient monitoring systems can serve continuous monitoring and determine variable symptoms of the patients. In this paper, we propose a patient monitoring system, which will be used for diagnosis and monitoring of sleep apnea by tracking the respiratory rate of patients with wearable sensor technology. The respiratory rate is detected using either an accelerometer sensor to be placed on the patients' abdomen or a temperature sensor to be placed on their noses. The proposed system offers an increase in the versatility of patient monitoring systems and offers an alternative new technology in sleep apnea diagnosis.Conference Object Citation - WoS: 2Citation - Scopus: 2Portatif ve Düşük Maliyetli Merceksiz Holografik Mikroskop Platformu ile Nanoparçacık Tespiti(IEEE, 2020) Delikoyun, Kerem; Keçili, Seren; Tekin, Hüseyin CumhurIn the biological and medical science, detection of biomolecule at very low concentration (<100 pg/mL) is of great importance and it is extensively used in the diagnosis of diseases, drug response monitoring and cancer research. For biomolecule detection tests, captured biomolecules generate signals (fluorescence, color, etc.), which are analyzed by trained personnel in bulky, high cost and fragile devices. However, for clinical applications, the access to these tests is very difficult at resource-limited settings. Lensless holographic microscopy provides high resolution imaging of samples without the need of expensive and fragile optical elements (mirror, lens, filter, etc.) used in traditional imaging technologies. While this technology offers a robust, portable and low-cost design, it enables fully automated processing of the sample image with digital processing schemes and this can also help eliminate user error. In this study, lensless holographic microscopy platform, which can be used in surface coverage assays for the detection of biomolecules, is proposed. It has been shown that nanoparticles (700-1200 nm) used as labels in surface coverage assays for the detection of biomolecules could be sensed on the platform. Therefore, it is anticipated that biomolecules detection could be realized rapidly and sensitively with this easy-to-use and low-cost imaging platform at the location where the high-level health institutions are not available and even at point-of-care settings.Conference Object Citation - WoS: 1Citation - Scopus: 2A Vacuum-Integrated Centrifugal Microfluidic Chip for Density-Based Separation of Microparticles(IEEE, 2021) Öksüz, Cemre; Tekin, Hüseyin CumhurHere we present a new vacuum-integrated centrifugal microfluidic chip for the density-based separation of microparticles. A sample was loaded in a fluidic channel using the gas permeability feature of polydimethylsiloxane (PDMS) membrane between fluidic and control channels. Vacutun was applied from control channel to drive a density media and then the sample containing microparticles in the dead-end fluidic channel. Afterwards, the chip was disconnected from the vacuum and it was centrifugated. If the sample contains microparticles denser than the density media, the microparticles are sedimented at the end of the microfluidic channel so that these particles can be separated from remaining the lower density particles. With this approach, we separated 1.09 g/mL microparticles with 82,6% efficiency and 99% purity from 1.02 g/mL microparticles. Separated particles in the microfluidic chip can also be inspected under a microscope for further analysis. This simple approach offers high efficient density-based separation of microparticles with close densities.Conference Object Citation - WoS: 3Citation - Scopus: 4Biofabrication of Cellular Structures Using Weightlessness as a Biotechnological Tool(IEEE, 2019) Anıl İnevi, Müge; Sarıgil, Öykü; Yaman, Sena; Yalçın Özuysal, Özden; Meşe, Gülistan; Tekin, Hüseyin Cumhur; Özçivici, EnginGravity is an important biomechanical signal effecting the morphology and function of organisms. Reduction of gravitational forces, as experienced during spaceflight, cause alterations in the biological systems. Magnetic levitation technique is one of the most recent ground-based technology to mimic weightlessness environment. In addition to providing a platform to investigate biological effects of the weightlessness, this platform presents a novel opportunity to biofabricate 3-dimensional (3D) structures in a scaffold-and nozzle-free fashion. In this study, various controllable self-assembled 3D living structures were fabricated via magnetic levitation technique. This strategy may offer an easy and cost-effective opportunity for a wide range of space biotechnology researches.Conference Object Citation - WoS: 4Citation - Scopus: 5Application of Magnetic Levitation Induced Weightlessness To Detect Cell Lineage(IEEE, 2019) Sarıgil, Öykü; Anıl İnevi, Müge; Yılmaz, Esra; Çağan, Melike; Meşe, Gülistan; Tekin, Hüseyin Cumhur; Özçivici, EnginIdentification and classification of bone marrow cells is an important step for molecular biology and therapeutic studies related to bone marrow disorders such as osteoporosis or obesity. In this study, we applied magnetic levitation technology to induce a weightlessness environment to detect adipocytes and osteoblasts based on their single cell density. This biotechnological method can be used for separation of heterogeneous populations such as bone marrow once adapted to a continuous microfluidic platform.