Chemical Engineering / Kimya Mühendisliği

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

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Author: search.filters.author.Altınkaya, SacideLanguage: search.filters.language.en

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  • Research Project
    Nanolifli yapıda, sinir büyüme faktörü yüklü mikro küreleri içeren jalatin bazlı doku iskelelerinin hazırlanması ve karakterizasyonu
    (TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2014) Altınkaya, Sacide; Erdal, Esra; Büyüköz, Melda
    In living organisms most of the tissues have the capability of regeneration; on the other hand, this situation is different in mammalian adult neural cells since they loose their ability of proliferation. Compared to peripheral nervous system, central nervous system has restricted regeneration capability which results in trauma, stroke and neuropathology etc. The first studies for the regeneration of nervous system concentrated on the use of autographs, tissue transplanted from one part of the body to another in the same individual, but it has limitations including short-age. Another type of investigation was allograft, which is transplantation of cells isolated from cadavers to the patient, but this approach is also not suitable because of host immune rejection. A new hope to cure neurodegenerative diseases appeared with biomaterials and tissue engineering studies. In this study, it is aimed to develop a novel, nanofibrous scaffolds with the capability of controlled releasing neural growth factor loaded in microspheres. Nanofibrous and oriented scaffolds were prepared from gelatin by a combination of thermally induced phase separation (TIPS), porogen-leaching and molding techniques while alginate microspheres were produced in oil in water emulsion through cross linking of alginate with calcium ions. The bioactivity of the growth factor released from microspheres was determined using PC12 cell line, derived from rat adrenal medulla and differentiate when treated with nerve growth factor. The scaffolds including connected pores with a high porosity, nanofibrous structure which mimic the extracellular matrix and properties similar to natural brain tissure were produced. Compared to solid walled scaffolds, nanofibrous scaffolds allow attachment of cells without any change in their morphologies. Model protein Į-chemotripsin and bovin serum albumin used for protecting the activity of nerve growth factor were loaded in alginate microspheres with an encapsulation efficiency of 100 %. It was found that NGF loaded into microspheres can maintain its activity and it can even differentiate PC-12 cells in a shorter time compared to NGF directly added into cell culture medium.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 16
    Partial Purification of Hen Egg White Lysozyme by Ethanol Precipitation Method and Determination of the Thermal Stability of Its Lyophilized Form
    (Türkiye Klinikleri Journal of Medical Sciences, 2007) Gemili, Seyhun; Umdu, Emin Selahattin; Yaprak, Nilgün; Üstok, Fatma Işık; Yener, Fatih Yalçın Güneş; Mecitoğlu Güçbilmez, Çiğdem; Altınkaya, Sacide; Yemenicioğlu, Ahmet
    Lysozyme was partially purified from hen egg white by precipitation of non-lysozyme protein impurities during incubation in the prence of ethanol. The thermal stability of the obtained partially purified enzyme was also characterized. The incubation of diluted egg white for 2-8 h in the presence of 20% ethanol was not very effective for the partial purification of lysozyme by precipitation of major egg white proteins; however, 4- to 6-h or 6-h to 8-h incubation of diluted egg white in the presence of 30% and 40% ethanol could be employed more effectively for partial purification of lysozyme. Without applying the incubation period, the highest specific activity was obtained by the treatment of egg white with 40% ethanol. Thus, ethanol at this concentration could be used for a continuous process of partial purification. For batch lysozyme purification, on the other hand, incubation in the presence of 30% ethanol was more appropriate. The activities and protein contents of dialyzed and lyophilized enzymes obtained by 6 h-incubation in the presence of 20%, 30%. and 40% ethanol precipitations were 1878, 6669, and 6115 U/mg powder, and 0.98, 0.90, and 0.93 mg protein per mg powder, respectively. The ranges of thermal inactivation parameters, such as D (D80°C = 29.2-59 min, D90°c = 8.8-21 min) and z (Z80-90°c = 17.4-22.3 °C) values of the enzyme, clearly indicated the moderate and variable heat stability of lyophilized lysozymes obtained from different batches of egg white.