WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 3Citation - Scopus: 4Magsity Platform: a Hybrid Magnetic Levitation-Based Lensless Holographic Microscope Platform for Liquid Density and Viscosity Measurements(Royal Soc Chemistry, 2025) Ince, Oyku Doyran; Tekin, Hüseyin Cumhur; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe viscosity and density of liquids are the most extensively studied material properties, as their accurate measurement is critical in various industries. Although developments in micro-viscometers have overcome the limitations of traditional bulky methods, more accessible technologies are required. Here, we introduce a novel magnetic levitation-based method to measure the viscosity and density of solutions in a microcapillary channel. This principle exploits microparticles as microsensors to correlate levitation time and height with solutions' viscosity and density, using buoyancy and drag forces. The platform has an integrated lensless holographic microscope, providing a hybrid system for in situ and precise measurements. By utilizing this hybrid technology, portable, rapid and cost-effective measurements can be conducted. This platform enables viscosity and density measurements within 7 minutes, achieving high accuracies of at least 97.7% and 99.9%, respectively, across an operation range of 0.84-5.09 cP and 1.00-1.09 g cm-3. The platform is utilized to clearly distinguish differences in the spent cell culture medium across various cell lines. This method, as presented, can be readily applied to measure a diverse array of liquids in multiple domains, encompassing biotechnology, medicine, and engineering.Review Citation - WoS: 7Citation - Scopus: 8Magnetic Levitation-Based Miniaturized Technologies for Advanced Diagnostics(Springernature, 2024) Tekin, Hüseyin Cumhur; Özçivici, Engin; Sarıgil, Öykü; Sarigil, Oyku; Guzelgulgen, Meltem; Kecili, Seren; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyTaking advantage of the magnetic gradients created using magnetic attraction and repulsion in miniaturized systems, magnetic levitation (MagLev) technology offers a unique capability to levitate, orient and spatially manipulate objects, including biological samples. MagLev systems that depend on the inherent diamagnetic properties of biological samples provide a rapid and label-free operation that can levitate objects based on their density. Density-based cellular and protein analysis based on levitation profiles holds important potential for medical diagnostics, as growing evidence categorizes density as an important variable to distinguish between healthy and disease states. The parallel processing capabilities of MagLev-based diagnostic systems and their integration with automated tools accelerates the collection of biological data. They also offer notable advantages over current diagnostic techniques that require costly and labor-intensive protocols, which may not be accessible in a low-resource setting. MagLev-based diagnostic systems are user-friendly, portable, and affordable, making remote and label-free applications possible. This review describes the recent progress in the application of MagLev principles to existing problems in the field of diagnostics and how they help discover the molecular- and cellular-level changes that accompany the disease or condition of interest. The critical parameters associated with MagLev-based diagnostic systems such as magnetic medium, magnets, sample holders, and imaging systems are discussed. The challenges and barriers that currently limit the clinical implications of MagLev-based diagnostic systems are outlined together with the potential solutions and future directions including the development of compact microfluidic systems and hybrid systems by leveraging the power of deep learning and artificial intelligence.Article Citation - WoS: 7Citation - Scopus: 7Colorimetric Detection of Serum Creatinine on a Miniaturized Platform Using Hue-Saturation Space Analysis(Nature Portfolio, 2024) Tarim, E. Alperay; Tekin, Hüseyin Cumhur; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyChronic kidney disease (CKD) is a widespread condition with considerable health and economic impacts globally. However, existing methodologies for serum creatinine assessment often involve prolonged wait times and sophisticated equipment, such as spectrometers, hindering real-time diagnosis and care. Innovative solutions like point-of-care (POC) devices are emerging to address these challenges. In this context, there is a recognized need for remote, regular, automated, and low-cost analysis of serum creatinine levels, given its role as a critical parameter for CKD diagnosis and management. This study introduces a miniaturized system with integrated heater elements designed for precise serum creatinine measurement. The system operates based on the Jaffe method and accurate serum creatinine measurement within a microreservoir chip. Smartphone-based image processing using the hue-saturation-value (HSV) color space was applied to captured images of microreservoirs. The creatinine analyses were conducted in serum with a limit of detection of similar to 0.4 mg/dL and limit of quantification of similar to 1.3 mg/dL. Smartphone-based image processing employing the HSV color space outperformed spectrometric analysis for creatinine measurement conducted in serum. This pioneering technology and smartphone-based processing offer the potential for decentralized renal function testing, which could significantly contribute to improved patient care. The miniaturized system offers a low-cost alternative ($87 per device), potentially reducing healthcare expenditures (similar to $0.5 per test) associated with CKD diagnosis and management. This innovation could greatly improve access to diagnosis and monitoring of CKD, especially in regions where access to sophisticated laboratory equipment is limited.Article Citation - WoS: 2Citation - Scopus: 2Investigating Influences of Intravenous Fluids on Huvec and U937 Monocyte Cell Lines Using the Magnetic Levitation Method(ROYAL SOC CHEMISTRY, 2023) Keçili, Seren; Tekin, Hüseyin Cumhur; Kaymaz, Sumeyra Vural; Özoğul, Beyzanur; Tekin, H. Cumhur; Elitaş, Meltem; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIntravenous fluids are being widely used in patients of all ages for preventing or treating dehydration in the intensive care units, surgeries in the operation rooms, or administering chemotherapeutic drugs at hospitals. Dextrose, Ringer, and NaCl solutions are widely received as intravenous fluids by hospitalized patients. Despite their widespread administration for over 100 years, studies on their influences on different cell types have been very limited. Increasing evidence suggests that treatment outcomes might be altered by the choice of the administered intravenous fluids. In this study, we investigated the influences of intravenous fluids on human endothelial (HUVEC) and monocyte (U937) cell lines using the magnetic levitation technique. Our magnetic levitation platform provides label-free manipulation of single cells without altering their phenotypic or genetic properties. It allows for monitoring and quantifying behavior of single cells by measuring their levitation heights, deformation indices, and areas. Our results indicate that HUVEC and U937 cell lines respond differently to different intravenous fluids. Dextrose solution decreased the viability of both cell lines while increasing the heterogeneity of areas, deformation, and levitation heights of HUVEC cells. We strongly believe that improved outcomes can be achieved when the influences of intravenous fluids on different cell types are revealed using robust, label-free, and efficient methods. Label-free analysis of cells exposed to intravenous fluids can be achieved through magnetic levitation technology coupled with cell-morphology characterization.Article Citation - WoS: 9Citation - Scopus: 12A Wearable Device Integrated With Deep Learning-Based Algorithms for the Analysis of Breath Patterns(Wiley, 2023) Tarım, Ergün Alperay; Tekin, Hüseyin Cumhur; Erimez, Büşra; Değirmenci, Mehmet; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologySleep problems are serious issues that make life difficult for all people, including sleep apnea. Sleep apnea, which causes breathlessness for more than 10 s, is linked to severe health problems due to the serious damage it can induce. To mitigate the risk of these disorders, the monitoring of patients has become increasingly challenging. Wearable technologies offer an effective healthcare solution for remote patient monitoring and diagnosis. A novel wearable system based on Arduino technology is introduced, specifically designed to monitor the breath patterns of patients. The analysis of breath data from patients holds great importance for the diagnosis and continuous monitoring of sleep apnea. To address this need, an advanced image processing system based on deep learning techniques is presented. This system automatically detects respiratory patterns, including inhalation, exhalation, and breathlessness. The device has an average of 97.6% sensitivity, 79.7% specificity, and 96% accuracy in identifying breath patterns. The designed device can offer patients and healthcare institutions a simple, inexpensive, noninvasive, and ergonomic system for the analysis of breath patterns that can be further extended for sleep apnea diagnosis.Review Citation - WoS: 52Citation - Scopus: 56Spheroid engineering in microfluidic devices(American Chemical Society, 2023) Tevlek, Atakan; Tekin, Hüseyin Cumhur; Keçili, Seren; Özçelik, Özge Solmaz; Kulah, Haluk; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyTwo-dimensional (2D) cell culture techniques are commonly employed to investigate biophysical and biochemical cellular responses. However, these culture methods, having monolayer cells, lack cell-cell and cell-extracellular matrix interactions, mimicking the cell microenvironment and multicellular organization. Three-dimensional (3D) cell culture methods enable equal transportation of nutrients, gas, and growth factors among cells and their microenvironment. Therefore, 3D cultures show similar cell proliferation, apoptosis, and differentiation properties to in vivo. A spheroid is defined as self-assembled 3D cell aggregates, and it closely mimics a cell microenvironment in vitro thanks to cell-cell/matrix interactions, which enables its use in several important applications in medical and clinical research. To fabricate a spheroid, conventional methods such as liquid overlay, hanging drop, and so forth are available. However, these labor-intensive methods result in low-throughput fabrication and uncontrollable spheroid sizes. On the other hand, microfluidic methods enable inexpensive and rapid fabrication of spheroids with high precision. Furthermore, fabricated spheroids can also be cultured in microfluidic devices for controllable cell perfusion, simulation of fluid shear effects, and mimicking of the microenvironment-like in vivo conditions. This review focuses on recent microfluidic spheroid fabrication techniques and also organ-on-a-chip applications of spheroids, which are used in different disease modeling and drug development studies.Conference Object Citation - Scopus: 1Magnetic Levitation-Based Adipose Tissue Engineering Using Horizontal Magnet Deployment(IEEE, 2020) Tekin, Hüseyin Cumhur; Anıl İnevi, Müge; Sarıgil, Öykü; Meşe Özçivici, Gülistan; Yılmaz, Esra; Sarıgil, Öykü; Özçelik, Özge; Meşe Özçivici, Gülistan; Meşe, Gülistan; Meşe Özçivici, Gülistan; Tekin, H. Cumhur; 01. Izmir Institute of Technology; 03.01. Department of Bioengineering; 04.03. Department of Molecular Biology and Genetics; 03. Faculty of Engineering; 04. Faculty of ScienceMagnetic 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) Meşe Özçivici, Gülistan; Tekin, Hüseyin Cumhur; Yaman, Sena; Anıl İnevi, Müge; Ünal, Yağmur Ceren; Meşe, Gülistan; 03.01. Department of Bioengineering; 01. Izmir Institute of Technology; 04.03. Department of Molecular Biology and Genetics; 03. Faculty of Engineering; 04. Faculty of ScienceLabel-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.Article Citation - WoS: 11Citation - Scopus: 11Absorbance-Based Detection of Arsenic in a Microfluidic System With Push-And Pumping(Elsevier, 2021) Karakuzu, Betül; Tekin, Hüseyin Cumhur; Gülmez, Yekta; Tekin, H. Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyRapid and portable analysis of arsenic (As) contamination in drinking water is very important due to its adverse health effects on humans. Available commercial detection kits have shown low sensitivity and selectivity in analysis, and also they can generate harmful by-products. Microfluidic-based approaches allow portable analysis with gold nanoparticles (AuNPs) as labels. However, they need complex surface modification steps that complicate detection protocols. Due to the lack of precise sensing and affordable solution, we focused on developing a microfluidic platform that uses a push-and-pull pumping method for sensitive detection of As. In this detection principle, a sample is introduced in the microfluidic channel modified with -SH functional groups where As can bind. Then, AuNPs are given in the channel and AuNPs bind on free -SH functional groups which are not allocated with As. Absorbance measurements are conducted to detect AuNPs absorbed on the surfaces and the resulting absorbance value is inversely proportional with As concentration. The method enables detection of As down to 2.2 mu g/L concentration levels in drinking water, which is well-below the allowed maximum As concentration of 10 mu g/L in the drinking waters by the World Health Organization (WHO). The paper reveals that multiple push-and-pull pumping of fixed volume of sample and AuNPs with a syringe pump can improve the binding efficiency in the microfluidic channel. With this technique, low amounts of sample (1 mL) and short total assay time (25 min) are sufficient to detect As.Conference Object Citation - WoS: 1Citation - Scopus: 5Otomatik Dijital İmge Analizi Kullanılarak Manyetik Levitasyon Platformunda Mikroparçaçıkların Özkütlelerinin Belirlenmesi(IEEE, 2018) Tekin, H. Cumhur; Tekin, Hüseyin Cumhur; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this study, a program, which will allow an automatic determination of density data by performing digital image analysis for a magnetic levitation platform used to determine the densities of microparticles, is presented. With this program, by processing the images of the magnetic levitation platform, the positions of the microparticles on the platform can be determined and the corresponding density values can be found. Thus, the densities of microparticles can be detected automatically at a resolution of 0.27 mg/mL.