Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Department: search.filters.department.Thesis (Master)--İzmir Institute of Technology, BioengineeringSubject: search.filters.subject.Nanofibers

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Now showing 1 - 3 of 3
  • Master Thesis
    The effects of photobioreactor average shear rate on chitin nanofiber production characteristics of the diatom cyclotella cryptica
    (01. Izmir Institute of Technology, 2024) Özkan, Altan; Özkan, Altan; Yılmaz, Benay Uzer; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Kitin biyomedikal uygulamalar açsıından çok yüksek potansiyelli doğal bir biyopolimerdir. Halihazırda, ticari kitin üretiminin çoğunluğu deniz ürünleri endüstrisi tarafından işlenen kabuklu deniz canlılarının atıkları kullanılarak yapılmaktadır. Diatom cinslerinden Cyclotella ve Thalassiosira kitin nanofiberlerini direkt olarak hücre duvarları üzerinde bulunan fultoportula adı verilen açıklıklardan dış ortama sentezleyebildikleri için kitin hasatı için sert ektraksiyon koşulları uygulanması gerekliliğini ortadan kaldırmaktadır. Bu çalışmada, Cyclotella cryptica CCMP 333 hücrelerinin kitin üretkenliğinin kabarcık kolon fotobiyoreaktörün havalandırma hızındaki farklılıktan kaynaklı maruz kaldıkları hidrolik kesme kuvvetinden nasıl etkilendiği iki aşamalı bir kültivasyon protokolü (birinci aşamada 0,020 mM silikon takviyesini müteakiben ikinci aşamada 1,80 mM silikon takviyesi) uygulanarak araştırılmıştır. Hücrelerin silikon starvasyonuna maruz bırakıldığı birinci aşamada havalandırma hızı 0,5 vvm olarak sabit tutulmuştur, 1,80 mM silikon takviyesinin ardından havalandırma hızlarının 0,25 vvm, 1 vvm ve 1,5 vvm olarak değiştirildiği 3 ayrı fotobiyoreaktör düzeneği kurulmuştur. Bu çalışma kapsamında ulaşılan maksimum kitin üretkenliği 852 mg/L olmuştur ve bu konsantrasyona silikon starvasyon aşamasında 0,5 vvm ile havalandırılan ve ardından 1,8 mM silikon takviyesi ile eş zamanlı olarak havalandırma hızının 1 vvm olarak değiştirildiği deney grubunda saptanmıştır. Cyclotella cryptica CCMP 333 hücre süspansiyonlarında serbest olarak ve hücreye bağlı olarak buluna kitin konsantrasyonları durağan faz sürecinde toplanan numuneler kullanılarak belirlenmiştir. Hücreye bağlı kitin nanofiberlerin konsantrasyonu ile havalandırma akış hızları arasında ters orantı olduğuna dair elde edilen sonuçlar büyük ölçekli diatom üretim tesislerinde hasatlanacak kitin nanofiberi miktarının maksimizasyonu için geliştirilecek stratejilere katkı sağlayacaktır.
  • Master Thesis
    Glucose Biosensor Applicatiın of Electrospun Polyvinyl Alacohol (pva) Fibers
    (Izmir Institute of Technology, 2016) Berber, Emine; Yıldız, Ümit Hakan; Demir, Mustafa Muammer; Demir, Mustafa Muammer; Yıldız, Ümit Hakan; 04.01. Department of Chemistry; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of Technology
    Electrospinning is a simple and versatile technique for the fabrication of polymeric nanofibrous membranes with high surface to volume ratio. Besides the large surface area of the fibrous membranes, their dimensional stability and flexibility allows the immobilization of biomolecules on to the nanofiber surfaces. Therefore, electrospun nanofibers have been extensively used in enzyme electrodes. This thesis examines the glucose biosensor application of electrospun polyvinyl alcohol (PVA) nanofibers – carbon nanotube (CNT) nanocomposite membranes. By manipulating the structural design and the composition of the nanocomposite membranes, glucose sensing efficiency of the five different enzyme electrodes a) Glucose oxidase (GOx) immobilized PVA electrospun electrode, b) Glucose oxidase (GOx) immobilized PVA electrospun electrode containing multi-walled carbon nanotube (MWCNT), c) Glucose oxidase (GOx) immobilized PVA electrospun electrode containing Poly(diallyldimethylammonium chloride) (PDDA) functionalized multi-walled carbon nanotube (MWCNT) d) Glucose oxidase (GOx) immobilized PVA electrospun electrode containing Poly(diallyldimethylammonium chloride) (PDDA) functionalized single-walled carbon nanotube (SWCNT), e) Interfacially cross-linked PVA electrospun electrode containing Poly(diallyldimethylammonium chloride) (PDDA) functionalized multi-walled carbon nanotube (MWCNT) were comperatively studied. PVA electrospun nanofibers were fabricated by using electrospinning technique. Morphology and average diameter of the fibers were characterized by using Scanning Electron Microscopy (SEM). Average diameter for the neat PVA electrospun fibers were 115 nm. Carbon nanotubes were oxidatively functionalized by acid treatment and addition of functional groups after acid treatment was proved by using Raman Spectroscopy. Glucose sensing activities of the electrodes were amperometrically measured at an applied voltage -0.5 V (vs. Ag/AgCl) in 0.1M phosphate buffer solution (PBS pH 7). Glucose detection sensitivies of the electrodes were calculated as 19.6, 27.7, 67.5, 44.4, 4.0 μA mM-1cm-2 respectively.
  • Master Thesis
    Development of Natural Compound-Loaded Nanofibers by Electrospinning
    (Izmir Institute of Technology, 2010) Balta, Ali Bora; Bayraktar, Oğuz; Bayraktar, Oğuz; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    In this study, the crude silk which is obtained from silkworm was turned into a silk solution after a serial procedure. Then, regenerated silk (foam) was obtained. The regenerated silk was dissolved in formic acid and polymer solution was prepared. After, nanofibers were produced by electrospinning. On the other hand, the content and antimicrobial activities of some plants were analyzed. Then all three forms of silk was absorbed with the olive leaf extract and extract desorption tests were done. As the first step of the study, the analyses of extracts which were obtained from four different plants were done. For this, total phenolic content and antioxidant capacity were found. In addition, minimum inhibition concentration (MIC) test and disc diffusion test were made for all extracts to Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa bacteria and Candida albicans fungi in order to determine their antimicrobial activity. While producing nanofibers from silk polymer with electrospinning method, different parameters such as concentration, voltage and distance were examined. Morphological characterization of nanofibers was done by scanning electron microscope (SEM). According to the results, the nanofiber with an optimum value which has a suitable diameter and structure was selected. With this nanofiber, the absorption and desorption tests of natural compound were made. The results were obtained by High pressure liquid chromatography (HPLC). Same adsorption and desorption tests were done also with the microfiber silk and regenerated silk (foam). As a result, it was shown by the controlled experiments that nanofibers were better for adsorption and desorption of natural compound when compared to microfiber silk and regenerated silk. In conclusion, nano-sized silk fibroin structures can be adsorbed with natural compounds in order to gain functionality. Using this kind of biofunctional products as medical textile and wound dressing material will be more advantageous when compared to current wound dressing materials.