Bioengineering / Biyomühendislik

Permanent URI for this collectionhttps://hdl.handle.net/11147/4529

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Author: search.filters.author.Tekin, Hüseyin CumhurPublisher: search.filters.publisher.Institute of Electrical and Electronics Engineers Inc.

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Now showing 1 - 5 of 5
  • Conference Object
    Citation - WoS: 5
    Citation - Scopus: 8
    Lensless Digital In-Line Holographic Microscopy for Space Biotechnology Applications
    (Institute of Electrical and Electronics Engineers Inc., 2019) Delikoyun, Kerem; Çine, Ersin; Anıl İnevi, Müge; Özuysal, Mustafa; Özçivici, Engin; Tekin, Hüseyin Cumhur
    Biomechanical changes at cellular level can dramatically affect living organisms in both aviation and space applications. Weightlessness induces morphological alteration of cells, which leads to tissue loss. Therefore, scientists have been studying the effect of weightlessness using cell culture based biological experiments using conventional microscopes. However, strict requirements regarding cost, weight and functionality limit the use of conventional microscopes in space environment. Lensless digital in-line holographic microscopy enables to use low-weight, low-cost and robust elements, such as a light emitting diode (LED), an aperture and an imaging sensor, instead of bulky, expensive and fragile optical elements, such as lenses, mirrors and filters. This technology offers a high field of view compared to conventional microscopes without affecting the resolution and it is also suitable for remote sensing applications with automated imaging capabilities. Here, we present a portable digital in-line holographic microscopy platform that allows to visualize cells and to analyze their viability in a microfluidic chip. The platform offers microscopic imaging with 1.55 mu m spatial resolution, 21.7 mm(2) field of view and image coloring capability. This platform could potentially play an important role in space biotechnology applications by enabling low-cost, high-resolution and portable monitoring of cells.
  • Conference Object
    Citation - WoS: 7
    Citation - Scopus: 7
    Cell Separation With Hybrid Magnetic Levitation-Based Lensless Holographic Microscopy Platform
    (Institute of Electrical and Electronics Engineers Inc., 2019) Delikoyun, Kerem; Yaman, Sena; Anıl İnevi, Müge; Özçivici, Engin; Tekin, Hüseyin Cumhur
    Separation of target cells in a heterogeneous solution is of great importance for clinical studies especially for immunology and oncology. Separated cells can be used for diagnostic applications ranging from whole blood counting to isolation of circulating tumor cells (CTC) for personalized medicine. Recent separation technologies rely on labelling and identifying target cells with variety of labelling principle such as fluorescence or magnetic tags. However, they require labor-intensive processes, long analysis time, and expensive chemical reagents and instrumentation. Hence, their usage is limited to well-equipped centralized laboratories. There is a need for a rapid, sensitive, low-cost and automated cell separation technology to disseminate usage of this technology even in rural areas. Magnetic levitation is a powerful cell separation method, which distinguishes cells based on their levitation heights depending on cell density. However, magnetic levitation-based separation technologies require traditional, bulky and expensive microscopes for analysis. Lensless digital inline holographic microscopy (LDIHM) systems are composed of a simple illumination system containing an LED, a pinhole, and an imaging sensor for high-resolution microscopic imaging, which eliminates needs of highly fragile and expensive optics as in traditional microscopy. Here, we introduced a novel hybrid and portable cell separation platform, where magnetic levitation technology is integrated with LDIHM system for automated analysis of cell levitation heights. Using this platform, three different cell lines are successfully separated. Live and dead cells having distinguished levitation heights can be also identified in the platform.
  • Conference Object
    Citation - Scopus: 2
    Density-Based Separation of Microparticles Using Magnetic Levitation Technology Integrated on Lensless Holographic Microscopy Platform
    (Institute of Electrical and Electronics Engineers Inc., 2019) Delikoyun, Kerem; Yaman, Sena; Tekin, Hüseyin Cumhur
    Microparticle/cell separation is one of the most important applications in the field of biomedical sciences particularly for cell sorting and protein assays. There are variety of different separation technologies introduced in the literature that the main limitations are large amount of sample, expensive chemical use besides of requirement of a labeling procedure (i.e. fluorescent/magnetic labeling), complex machinery, and high operational costs. Magnetic levitation-based separation offers simple, rapid and precise separation of microparticles based on their densities by suspending them in a glass microcapillary between two opposing magnets. Traditionally, magnetic levitation-based microparticle separation and identification procedure is performed by imaging under bulky microscopes composed of fragile and expensive optics and require trained personnel to operate which makes the whole procedure costly, time consuming and prone to human error. Lensless digital inline holographic microscope (LDIHM) eliminates the need for sophisticated optics by replacing simple illumination and recording scheme that can be reduced into few widely-Available and cost-effective components. Thus, inspection procedure is mostly carried out on digitally processing captured holograms so that dependency on optical components and human error is dramatically reduced alongside using cost-effective and handheld device. Here, we introduce a novel hybrid platform that brings the advantages of magnetic levitation system with lensless digital inline holographic microscope for precise separation and identification of microparticles based on their densities. In the platform, it was shown that 1.026 g/mL and 1.090 g/mL microparticles were successfully identified. © 2019 IEEE.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 3
    Microfluidic Platform for Sorting Materials Based on Their Densities Using Magnetic Levitation
    (Institute of Electrical and Electronics Engineers Inc., 2019) Yılmaz, Esra; Özçivici, Engin; Tekin, Hüseyin Cumhur
    Circulating Tumor Cells (CTCs) play a vital role in cancer diagnosis, prognosis and personalized medicine. However, CTCs are extremely rare in blood (i.e., down to 1-100 CTC per 1 mL human blood) and hard to isolate because of the heterogeneity of CTCs in biomarker expression. The current CTC separation and identification techniques use numerous differences between cells such as size, electric charges, density and expression of cell surface markers. However, these techniques have many limitations in terms of laborious sample preparation steps, inconsistent results caused by low specificity and efficiency and high cost. Hence, there is no standard method for isolating CTCs yet. With this study, it was aimed to fill the gap in CTC isolation and identification by proposing to develop a new method based on magnetic levitation principle, which has recently been demonstrated as a highly acceptable method for biological characterization of cells and monitoring of their cellular events. In this study, we have developed a new label-free microfluidic sorter to separate microparticles/cells based on their densities using magnetic levitation principle. Two different density microparticles (1.02 g/mL and 1.09 g/ mL) have been sorted and quantified in a continuous flow using a set of permanent magnets located in a 3D printed structure surrounding the microfluidic channel. This device can be used for rapid, low cost and label-free in-vitro diagnosis of cancer by sorting CTCs from whole blood in a high-Throughput manner. The sorted cells might further be used for downstream analysis for personalized and precision medicine. © 2019 IEEE.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    Active Mixing Strategy With Electromechanical Platform for Lab-On Applications
    (Institute of Electrical and Electronics Engineers Inc., 2019) Karakuzu, Betül; Özçivici, Engin; Tekin, Hüseyin Cumhur; Tarım, E. Alperay
    The main purpose of this study is to present a new active mixing strategy that can be used for lab-on-A-chip applications to shorten analysis time. An electromechanical platform composed of stepper and DC motors is designed and manufactured. This platform allows rapid mixing in microwells of a polydimethylsiloxane chip for analysis. Mixing in microwells is performed with a stirring bar spun automatically using the electromechanical platform. Mixing experiments performed at different spinning speeds and different time intervals on the platform. It was observed that mixing was achieved only in 300 ms inside 100 ?L microwell using 4300 revolutions per minute (rpm) spinning speeds. Hence, the proposed mixing strategy showed 200-fold faster mixing than pure diffusion-based mixing. © 2019 IEEE.