Bioengineering / Biyomühendislik
Permanent URI for this collectionhttps://hdl.handle.net/11147/4529
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Article Citation - Scopus: 11Μdacs 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 CumhurCirculating 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)Conference Object Biofabrication of Scaffold-Free 3d Cellular Structures Using Magnetic Levitational Assembly To Study Cardiac Toxicity(Mary Ann Liebert, 2023) Yıldız, Ahu Arslan; Arslan Yıldız, Ahu; Onbaş, RabiaSpheroids are one of the well-characterized 3D cell culture approaches for drug screening and therapeutic studies. Magnetic levitation (MagLev) is a newly developing approach to form 3D cellular structures and spheroids [1,2,3]. Magnetic levitational assembly of cells provides rapid, simple, cost-effective 3D cell culture formation while ensuring scaffold-free microenvironment. Here, our efforts are summarized in designing new magnetic levitation platform and biofabrication of 3D cellular entities via magnetic levitation for tissue engineering. Magnetic levitation and guidance of cells were provided by using a paramagnetic agent to fabricate scaffold-free 3D cellular structures. The parameters of cell density, paramagnetic agent concentration, and culturing time were optimized to obtain 3D cardiac cellular structures with tunable size, circularity, and high cell viability. Cellular and extracellular components of the 3D cellular structures were demonstrated via immunofluorescent staining. Also, 3D cardiac cellular structures showed more resistance to drug exposure compared to 2D control. In conclusion, MagLev methodology offers an easy and efficient way to fabricate 3D cellular structures for drug screening studies.Review Citation - WoS: 52Citation - Scopus: 56Spheroid engineering in microfluidic devices(American Chemical Society, 2023) Tevlek, Atakan; Keçili, Seren; Özçelik, Özge Solmaz; Kulah, Haluk; Tekin, H. CumhurTwo-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 Biofabrication by Magnetic Levitational Assembly of Cells Into Defined 3d Cellular Structures(Mary Ann Liebert, 2022) Arslan Yıldız, AhuIn the field of tissue engineering 3D (three dimensional) cell culture studies have increased over the years since they are the closest models of real tissues. Compared to the 2D models, there is a big improvement on cell growth, morphology, differentiation, gene and protein expression when 3D system is utilized. Because of these advantages 3D cell culture is commonly used for tissue engineering, artificial organ technologies, regenerative medicine, drug development, drug screening and stem cell studies. Despite promising advances in these areas, there are still unmet needs to completely fulfill all requirements. Sophisticated tools, methodologies and materials are still required for further development in tissue engineering; especially for cellular assembly, single cell level control, easy control over biofabrication system, direct forward cellular imaging and analysis. Recently, magnetic levitation technology that overcomes most of the above mentioned problems, has been utilized for the formation of 3D cellular structures. Magnetic levitational assembly of cells provide rapid, simple, cost-effective 3D cell culture formation while ensuring scaffold-free microenvironment.Article Citation - Scopus: 6Sensitive and Rapid Protein Assay Via Magnetic Levitation(Elsevier, 2022) Sözmen, Alper Baran; Arslan Yıldız, AhuMagnetic 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: 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.Article Citation - WoS: 24Citation - Scopus: 30Hologlev: 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, ÖzdenIn 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: 22Citation - Scopus: 26Magnetic 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, EnginDiamagnetic 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.Article Citation - WoS: 16Citation - Scopus: 13Fabrication of Tunable 3d Cellular Structures in High Volume Using Magnetic Levitation Guided Assembly(American Chemical Society, 2021) Onbas, Rabia; Arslan Yıldız, AhuTunable and reproducible size with high circularity is an important limitation to obtain three-dimensional (3D) cellular structures and spheroids in scaffold free tissue engineering approaches. Here, we present a facile methodology based on magnetic levitation (MagLev) to fabricate 3D cellular structures rapidly and easily in high-volume and low magnetic field. In this study, 3D cellular structures were fabricated using magnetic levitation directed assembly where cells are suspended and self-assembled by contactless magnetic manipulation in the presence of a paramagnetic agent. The effect of cell seeding density, culture time, and paramagnetic agent concentration on the formation of 3D cellular structures was evaluated for NIH/3T3 mouse fibroblast cells. In addition, magnetic levitation guided cellular assembly and 3D tumor spheroid formation was examined for five different cancer cell lines: MCF7 (human epithelial breast adenocarcinoma), MDA-MB-231 (human epithelial breast adenocarcinoma), SHSYSY (human bone-marrow neuroblastoma), PC-12 (rat adrenal gland pheochromocytoma), and HeLa (human epithelial cervix adenocarcinoma). Moreover, formation of a 3D coculture model was successfully observed by using MDA-MB-231 dsRED and MDA-MB-231 GFP cells. Taken together, these results indicate that the developed MagLev setup provides an easy and efficient way to fabricate 3D cellular structures and may be a feasible alternative to conventional methodologies for cellular/multicellular studies.
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