Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Subject: search.filters.subject.Magnetic levitation

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Now showing 1 - 10 of 23
  • Review
    Citation - WoS: 7
    Citation - Scopus: 8
    Magnetic Levitation-Based Miniaturized Technologies for Advanced Diagnostics
    (Springernature, 2024) Karakuzu, Betul; Inevi, Muge Anil; Tarim, E. Alperay; Sarigil, Oyku; Guzelgulgen, Meltem; Kecili, Seren; Tekin, H. Cumhur
    Taking 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.
  • Conference Paper
    Magnetic Levitation-Based Endothelial Cell Sorting
    (Institute of Electrical and Electronics Engineers Inc., 2023) Ozcan, H.A.; Kecili, S.; Tekin, H.C.
    Cell sorting for rare cells is crucial for diagnostic purposes. Circulating Endothelial Cells (CECs) can be used as cardiovascular disease markers. Due to the rareness of the CECs in the blood, an accurate, easy, cost and time-effective sorting method is a need. Magnetic levitation is a promising technique for observing differences in the average height of endothelial and white blood cells which does not require any labeling. This study aims to show that the magnetic levitation principle can be used for sorting endothelial cells from the blood. By using paramagnetic medium concentrations of 10 mM and 50 mM, the average levitation height between HUVECs used as a model endothelial cells and U937 cells used as model of white blood cells was measured as 65 μm and 32 μm, respectively. Since there is a significant difference in levitation height for HUVECs and U937 cells, magnetic levitation technology exhibits promising potential for the precise sorting of endothelial cells. © 2023 IEEE.
  • Conference Object
    Magnetic Levitation-Based Viscosity Measurement in a Microcappilary Channel
    (Chemical and Biological Microsystems Society, 2022) Doyran, O.; Tekin, H.C.
    Viscosity, has been known as the key rheological parameter, to characterize biological, chemical and physical material properties. In this work, we have developed a magnetic levitation-based viscosity measurement method in a microcapillary channel. For this purpose, polymer microspheres are utilized as microsensors to correlate solution viscosity to microspheres' velocity while microspheres are balanced at a stable levitation position. This inexpensive and practical system enables rapid viscosity measurement from low amount of sample. © 2022 MicroTAS 2022 - 26th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
  • Article
    Citation - Scopus: 11
    Μdacs Platform: a Hybrid Microfluidic Platform Using Magnetic Levitation Technique and Integrating Magnetic, Gravitational, and Drag Forces for Density-Based Rare Cancer Cell Sorting
    (Elsevier, 2023) Keçili, Seren; Yılmaz, Esra; Özçelik, Özge Solmaz; Anıl İnevi, Müge; Günyüz, Zehra Elif; Yalçın Özuysal, Özden; Özçivici, Engin; Tekin, Hüseyin Cumhur
    Circulating tumor cells (CTCs) are crucial indicators of cancer metastasis. However, their rarity in the bloodstream and the heterogeneity of their surface biomarkers present challenges for their isolation. Here, we developed a hybrid microfluidic platform (microfluidic-based density-associated cell sorting (µDACS) platform) that utilizes density as a biophysical marker to sort cancer cells from the population of white blood cells (WBCs). The platform utilizes the magnetic levitation technique on a microfluidic chip to sort cells based on their specific density ranges, operating under a continuous flow condition. By harnessing magnetic, gravitational, and drag forces, the platform efficiently separates cells. This approach involves a microfluidic chip equipped with a microseparator, which directs cells into top and bottom outlets depending on their levitation heights, which are inversely proportional to their densities. Hence, low-density cancer cells are collected from the top outlet, while high-density WBCs are collected from the bottom outlet. We optimized the sorting efficiency by varying the flow rates, and concentrations of the sorting medium's paramagnetic properties using standard densities of polymeric microspheres. To demonstrate the platform's applicability, we performed hybrid microfluidic sorting on MDA-MB-231 human breast cancer cells and U-937 human monocytes. The results showed efficient sorting of rare cancer cells (≥100 cells/mL) from serum samples, achieving a sorting efficiency of ∼70% at a fast-processing speed of 1 mL h−1. This label-free approach holds promise for rapid and cost-effective CTC sorting, facilitating in-vitro diagnosis and prognosis of cancer. © 2023 The Author(s)
  • Review
    Citation - WoS: 52
    Citation - Scopus: 56
    Spheroid engineering in microfluidic devices
    (American Chemical Society, 2023) Tevlek, Atakan; Keçili, Seren; Özçelik, Özge Solmaz; Kulah, Haluk; Tekin, H. Cumhur
    Two-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.
  • Article
    Citation - Scopus: 6
    Sensitive and Rapid Protein Assay Via Magnetic Levitation
    (Elsevier, 2022) Sözmen, Alper Baran; Arslan Yıldız, Ahu
    Magnetic levitation (MagLev) is a newly emerging methodology for biosensing that provides a density-based analysis, which is highly sensitive and versatile. In this study, a magnetic levitation based sensor platform was used for protein detection; and sensor platform optimization was performed for both sensitivity and resolution. Bovine Serum Albumin (BSA) was used as a model protein and detection of BSA was carried out by antibody functionalized polystyrene microspheres (PSMs). Various sizes of PSMs were examined and their performances were compared by statistical analyses in terms of limit of detection (LOD), sensitivity, and resolution. Quantification of the protein was done based on the magnetic levitation height differences of antibody functionalized PSMs. For optimization of the methodology, varied PSMs were utilized, and standardization of PSM diameter, concentration of the antibody to be functionalized, and PSM dilution rates were carried out. In conclusion, 20 μm PSMs diluted to 0.005% W/V and functionalized with anti-BSA antibody at a concentration of 28 μg/ml were determined to provide the best resolution for BSA detection. A dynamic range of 100 nM to 1 mM was observed with an LOD value of 4.1 ng/ml. This sensing platform promises a novel approach with a diverse application field and it provides rapid, consistent, and reproducible results with high resolution and sensitivity.
  • Conference Object
    Citation - Scopus: 1
    Magnetic 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. Cumhur
    Magnetic 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, Gülistan
    Label-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: 24
    Citation - Scopus: 30
    Hologlev: a Hybrid Magnetic Levitation Platform Integrated With Lensless Holographic Microscopy for Density-Based Cell Analysis
    (American Chemical Society, 2021) Delikoyun, Kerem; Yaman, Sena; Yılmaz, Esra; Sarıgil, Öykü; Anıl İnevi, Müge; Telli, Kübra; Yalçın Özuysal, Özden
    In clinical practice, a variety of diagnostic applications require the identification of target cells. Density has been used as a physical marker to distinguish cell populations since metabolic activities could alter the cell densities. Magnetic levitation offers great promise for separating cells at the single cell level within heterogeneous populations with respect to cell densities. Traditional magnetic levitation platforms need bulky and precise optical microscopes to visualize levitated cells. Moreover, the evaluation process of cell densities is cumbersome, which also requires trained personnel for operation. In this work, we introduce a device (HologLev) as a fusion of the magnetic levitation principle and lensless digital inline holographic microscopy (LDIHM). LDIHM provides ease of use by getting rid of bulky and expensive optics. By placing an imaging sensor just beneath the microcapillary channel without any lenses, recorded holograms are processed for determining cell densities through a fully automated digital image processing scheme. The device costs less than $100 and has a compact design that can fit into a pocket. We perform viability tests on the device by levitating three different cell lines (MDA-MB-231, U937, D1 ORL UVA) and comparing them against their dead correspondents. We also tested the differentiation of mouse osteoblastic (7F2) cells by monitoring characteristic variations in their density. Last, the response of MDA-MB-231 cancer cells to a chemotherapy drug was demonstrated in our platform. HologLev provides cost-effective, label-free, fully automated cell analysis in a compact design that could be highly desirable for laboratory and point-of-care testing applications.
  • Article
    Citation - WoS: 22
    Citation - Scopus: 26
    Magnetic Levitation Assisted Biofabrication, Culture, and Manipulation of 3d Cellular Structures Using a Ring Magnet Based Setup
    (Wiley, 2021) Anıl İnevi, Müge; Delikoyun, Kerem; Meşe Özçivici, Gülistan; Tekin, Hüseyin Cumhur; Özçivici, Engin
    Diamagnetic levitation is an emerging technology for remote manipulation of cells in cell and tissue level applications. Low-cost magnetic levitation configurations using permanent magnets are commonly composed of a culture chamber physically sandwiched between two block magnets that limit working volume and applicability. This work describes a single ring magnet-based magnetic levitation system to eliminate physical limitations for biofabrication. Developed configuration utilizes sample culture volume for construct size manipulation and long-term maintenance. Furthermore, our configuration enables convenient transfer of liquid or solid phases during the levitation. Before biofabrication, we first calibrated/ the platform for levitation with polymeric beads, considering the single cell density range of viable cells. By taking advantage of magnetic focusing and cellular self-assembly, millimeter-sized 3D structures were formed and maintained in the system allowing easy and on-site intervention in cell culture with an open operational space. We demonstrated that the levitation protocol could be adapted for levitation of various cell types (i.e., stem cell, adipocyte and cancer cell) representing cells of different densities by modifying the paramagnetic ion concentration that could be also reduced by manipulating the density of the medium. This technique allowed the manipulation and merging of separately formed 3D biological units, as well as the hybrid biofabrication with biopolymers. In conclusion, we believe that this platform will serve as an important tool in broad fields such as bottom-up tissue engineering, drug discovery and developmental biology.