Chemical Engineering / Kimya Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/14

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Institution Author: search.filters.institutionAuthor.Altıok, Duygu

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  • Conference Object
    Citation - Scopus: 4
    Trans-resveratrol’ün Kitosan Mikroküreler İçerisindeki Kararlılığı
    (Institute of Electrical and Electronics Engineers Inc., 2009) Altıok, Duygu; Altıok, Evren; Bayraktar, Oğuz; Tıhmınlıoğlu, Funda
    trans-Resveratrol, (3,5,4?-trihydroxy-trans-stilbene), a phenolic compound present in some plant species, have been shown to posses antioxidative, anticarcinogenic and antitumour properties. However, under UV light, it turns into -cis form and looses its bioactivity.This study aims to increase the stability of trans-resveratrol by loading it into chitosan microspheres. Within this context, the trans-resveratrol loaded chitosan microspheres was produced by spray drying and then the resultant microspheres were characterized. The particle size and the surface morphology of resultant microspheres were investigated by scanning electron microscope (SEM) and the thermal properties were determined by thermogravimetry analyser(TGA). The stability of free and that of inside the microspheres was determined by high performance liquid chromatography (HPLC). It was found that the stability of trans-resveratrol incorporated into chitosan microspheres kept constant. ©2009 IEEE.
  • Article
    Citation - WoS: 25
    Citation - Scopus: 29
    Antibacterial Properties of Silk Fibroin/Chitosan Blend Films Loaded With Plant Extract
    (Korean Fiber Society, 2010) Başal, Güldemet; Altıok, Duygu; Bayraktar, Oğuz
    The silk fibroin (SF)/chitosan (CHI) blend films were prepared by dissolving them in formic acid. The morphology of the films was examined by scanning electron microscopy (SEM). The roughness of the membranes was determined by atomic force microscopy (AFM). These films were treated with the extracts of Pistacia terebinthus, Pistacia lentiscus, and Hypericum empetrifolium. Folin-Ciocalteu assay was used to determine the amount of total phenols adsorbed on these blend films. The antibacterial properties of films were tested using disc diffusion and turbidity measurement methods against Escherichia coli and Staphylococcus epidermidis. The release of adsorbed phenolics from the film surface resulted in antibacterial properties. © The Korean Fiber Society and Springer Netherlands 2010.
  • Patent
    Essential Oil Loaded Mucoadhesive Nanocomposite Delivery System for Gastrointestinal System
    (World Intellectual Property Organization, 2016)
    Current treatments for H. pylori infection are not efficient enough due to poor diffusion of antibiotics to mucus layer, low stability, side effects and insufficient residence time of antibiotics in gut, antibiotic resistance of H. pylori and allergy of patients against antibiotics. Therefore, alternative therapies including new drugs and therapeutic approaches with enhanced action and reduced side effects are needed to achieve high eradication rate of the bacteria. This invention is related with eradication and/or prevention therapy of H.pylori that provides better diffusion to mucus layer and stabilization in gastric conditions. This invention comprises the local treatment of H.pylori and/or improving the drug release profiles of encapsulated essential oil within chitosan/nanoclay microspheres which could be located in gastrointestinal system. Therefore, the aim of this invention is to encapsulate essential oil in gastroretentive chitosan/nanoclay spheres which has antimicrobial activity against H.pylori and release in a controlled manner in the prior to art.
  • Article
    Citation - WoS: 347
    Citation - Scopus: 397
    Physical, Antibacterial and Antioxidant Properties of Chitosan Films Incorporated With Thyme Oil for Potential Wound Healing Applications
    (Springer Verlag, 2010) Altıok, Duygu; Altıok, Evren; Tıhmınlıoğlu, Funda
    Chitosan films incorporated with thyme oil for potential applications of wound dressing were successfully prepared by solvent casting method. The water vapor permeability, oxygen transmission rate, and mechanical properties of the films were determined. Surface and cross-section morphologies and the film thicknesses were determined by Scanning Electron Microscopy (SEM). Fourier transform infrared (FT-IR) spectroscopy was conducted to determine functional group interactions between the chitosan and thyme oil. Thermal behaviors of the films were analyzed by Thermal Gravimetry (TGA) and Differential Scanning Calorimetry (DSC). In addition, the antimicrobial and the antioxidant activities of the films were investigated. The antimicrobial test was carried by agar diffusion method and the growth inhibition effects of the films including different amount of thyme oil were tested on the gram negative microorganisms of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and a gram positive microorganism of Staphylococcus aureus. The minimum thyme oil concentration in chitosan films showing the antimicrobial activity on all microorganisms used in the study was found as 1.2 % (v/v). In addition, this concentration showed the highest antioxidant activity due to mainly the carvacrol in thyme oil. Water vapor permeability and oxygen transmission rate of the films slightly increased, however, mechanical properties decreased with thyme oil incorporation. The results revealed that the thyme oil has a good potential to be incorporated into chitosan to make antibacterial and permeable films for wound healing applications. © 2010 Springer Science+Business Media, LLC.