Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Image-Based Bioassays in Microfluidic Devices(Izmir Institute of Technology, 2023) Doyran, Öykü; Teki̇n, Hüseyi̇n CumhurSon zamanlarda, mikroakışkan uygulamalar, tıbbi bozuklukların teşhisini ve izlenmesini amaçlayan minyatür cihazlarla, standart laboratuvar prosedürlerinin yerini almıştır. İyi tanınan geleneksel mikroskobik teknikler, hala alışılagelmiş olarak mikroakışkan teknolojilerinde görüntüleme için kullanılmaktadır. Ancak bu mikroskopların hantal ve pahalı yapıları, yeni nesil hasta başı test cihazları ile uyumlu değildir. Minyatür cihazlarda optik elemanların uygulanması, ölçüm doğruluğu ve kesinliğinin yanı sıra taşınabilir enstrümantasyon sunar. Spesifik olarak, lenssiz görüntüleme teknolojilerinin mikro teknolojilerle entegrasyonu, yeni cihazlar geliştirmenin yolunu açmıştır. Bu tezde entegre lenssiz holografik mikroskopların iki farklı uygulaması sunulmuştur. İlk uygulama, boyutlarına ve morfolojilerine göre kanda sirküle eden tümör mikroembolilerini lökositlerden ayırmak, saflaştırmak ve izole etmek için yeni bir lenssiz holografik mikroskop entegreli mikroakışkan tabanlı filtreleme yönteminin geliştirilmesini içermektedir. Geliştirilen yöntem, mikrofiltrasyon ve lenssiz holografik mikroskop teknolojilerinin avantajlarını kullanarak, ticari hücre ayırma cihazlarıyla karşılaştırılabilir şekilde kanda sirküle eden tümör mikroemboli ayırma verimliliği ve saflığı sağlamıştır. Ayrıca, lenssiz holografik mikroskop entegre manyetik levitasyon tabanlı sıvı viskozitesi ve özkütle ölçümü olarak başka bir yeni yöntem tanıtılmıştır. Bu yöntemde, sıvıların özkütle ve viskozitelerini belirlemek için mikrosensör olarak mikropartiküller ölçüm yapılacak sıvı içinde kullanılmıştır. Bu parçacıkların levitasyon yüksekliği ve hızı sıvının özkütlesi ve viskozitesi ile ilişkilendirilmiştir. Bu tez kapsamında sunulan, mikroakışkan tabanlı teknolojilere entegre lenssiz holografik mikroskop sistemleri, uygun maliyetli ve taşınabilir görüntü tabanlı yeni cihazların geliştirilmesinin önünü açabilecektir.Master Thesis Cell Separation in Microfluidic Devices(01. Izmir Institute of Technology, 2022) Öksüz, Cemre; Tekin, Hüseyin CumhurCell separation is used to separate homogeneous and individual cell classes from a heterogeneous cell population. The efficiency and purity of these separated cells are of great importance in personalized medicine, regenerative medicine, disease monitoring and drug testing as well as in the therapeutic and diagnostic research. In this thesis, different microfluidic approaches were presented for cell separation. With this regard, a closed channel vacuum-integrated microfluidic chip was developed using an air permeability of a Polydimethylsiloxane and density-based separation of microparticles was performed. Besides, a centrifugal microfluidic system, Spinochip, was developed with one reservoir as inlet and outlet for the first time and different fluid manipulations were shown in the system. The system was applied to clinical tests of hematocrit measurements and white blood cell estimation using real patient samples. The developed system offered correlated results with clinical results. In addition to closed channel microfluidics, negative-magnetophoresis microfluidic chip was demonstrated for the size-based separation of microparticles and cells. In this regard, capturing rate of breast cancer cells (MCF-7) and human monocyte cells (U937) was investigated. The results showed that the approaches presented here could promote to the microfluidic studies for size-based cell separation.Master Thesis Magnetic-Based Cell Manipulation in Microfluidic Devices(01. Izmir Institute of Technology, 2022) Özçelik, Özge Solmaz; Tekin, Hüseyin CumhurCell manipulation is the concept of altering cell movement. Different manipulation techniques have been demonstrated with microfluidic systems for various studies such as tissue engineering, circulating tumor cell (CTC) filtering, and other biomedical applications. For instance, cell patterning and filtering studies are being developed through different manipulation approaches in microfluidic platforms where one of these approaches is the magnetophoresis principle method. Positive and negative magnetophoresis can be utilized generally through labeling or non-labeling, respectively. In this thesis, two different cell manipulation platforms using negative magnetophoresis were developed for cell patterning and cell filtration applications. These platforms allow several advantages such as simple fabrication, easy control, and low cost. Compared to other devices, the developed microfluidic platforms do not require any labeling process for cells for magnetic manipulation. In the patterning platform, microparticle and cell patterns were formed inside a simple microfluidic channel with different tilted angles in <1.5 hours. Furthermore, in the filtration platform, large microparticles were separated from small microparticles with 98.25% trapping efficiency. Live/dead cell separation of human monocyte macrophage cells (U937) under different flow rates was also investigated. The suggested platforms could be useful for label-free magnetic cell patterning and filtering in biomedical applications.Master Thesis Design and Development of Paper-Based Microfluidics for Point-Of Applications(01. Izmir Institute of Technology, 2020) Özefe, Fatih; Arslan Yıldız, Ahu; Yıldız, Ümit HakanPaper-based microfluidics is a subarea of microfluidics which is recently used in various applications from diagnostics to environmental monitoring, and to food safety. In such microfluidic systems, a test platform is formed from a paper substrate instead of silicon and polymers, such as poly-dimethylsiloxane, poly-methyl methacrylate, and etc. The main goal of this thesis is the development and fabrication of a paper-based microfluidic device (μPAD), which could be used in point-of-care (POC) applications. The characterizations of μPADs, which were fabricated via laser ablation methodology, were performed in terms of their surface and barrier characteristics, and liquid sample flows within μPADs. Depending on the characterization, nine different fabrication parameters, 10P40S (10%Power & 40%Speed), 10P60S, 20P90S, 30P50S, 30P100S, 40P80S, 40P100S, 70P80S, and 70P100S, were identified as optimized fabrication parameters. Also, two designed models of μPADs, 1S4T-Type2 and 1S4T-Type3, were selected to be used in the detection of BSA and recombinant Hepatitis C Virus (HCV) protein. The BSA and HCV (1 mg/ml) in PBS solution were successfully detected via naked eye depending on the colorimetric sensing through micro-paper enzyme linked immunosorbent assay (μP-ELISA) protocol. Moreover, the limit of detection (LoD) values for HCV were determined in 1S4T-Type2 μPAD as 1.000, 0.883, and 0.796 ng/ml when the detection was performed via naked eye, smart-phone, and bright-field microscope, respectively. Also, the easily-disposable 1S4T-Type2 μPAD provided 14 times faster and 45 times cheaper detection of HCV compared to conventional ELISA techniques. Consequently, the developed 1S4T-Type2 μPAD presented low-cost, easy-to-use, and rapid detection of HCV as POC devices.Master Thesis Design and Fabrication of Microfluidic Device That Allows Investigation of Distance Dependent Interactions of Two Different Cell Types(Izmir Institute of Technology, 2014) Sağlam, Murat; Pesen Okvur, Devrim; Özyüzer, LütfiThe main studies of in this thesis, the mold and a microfluidic device are achieved by using SU-8 photoresist and PDMS polymer. Firstly, molds are obtained which are thickness ranging from 30 to 400 μm by using SU-8 photoresist with UV lithography technique and this molding will use for shaping polydimethylsiloxane (PDMS) polymer. Finally, PDMS molds combined with the glass surface to create a three dimensional reservoirs. Microfluidic device that allows investigation of distance dependent interactions, two factors are positioned at certain distances from each other and the microfluidic device is allowed to investigation of distance dependent interaction of two factors. There is an alternating width channel between two channels which have each of two factors. These three channels are separated from each other by colonnades, not by walls, therefore physical, chemical and biological interactions are possible between the factors. Necessary physical, chemical, and biological conditioning can be provided by the reservoirs which are neighbor of channels including factors. Microfluidic chip has a lot of advantages that are small liquid volumes (pL-μL), precise spatial & temporal control, successfully mimic the physiological context, highthroughput analysis, low fabrication costs; portable and safer therefore it facilitates us to refine our methods of analysis and development in cell biology investigations and determining the content of chemical samples.