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Öğe Biomedical applications of polyglycolic acid (PGA)(2017) Göktürk, Ersen; Erdal, HüseyinBiodegradable polymers have a great potential and widely used in biomedical applications due to their biodegradability and biocompatibility. Biodegradable polymers contain hydrolytically unstable functional groups (such as esters, anhydrides and etc.) in their backbone. These hydrolytically unstable functional groups can be hydrolyzed, or eaten by microorganisms, and degradability happens. Biodegradable polymers can be effectively used for several biomedical applications such as drug delivery, dental, orthopedic and tissue engineering. Polyglycolic acid (PGA) is a desired material for physicians due to its excellent degradation behaviour. However, limited research based on PGA polymers has been studied in biomedical applications due to insolubility of PGA in most of the solvents and rapid degradation of PGA. This review will focus on the improvements made in the development of hydrolytically degradable PGA in biomedical fields.Öğe Comparison of quality properties of the Iranian Saffron (Crocus sativus L.) and Saffron grown in macro and micro locations in Turkey(2021) Asil, Hasan; Göktürk, ErsenIn this study, volatile and bioactive compositions of saffron samples collected from Khorasani region in Iran Razavi and different locations in Turkey containing Hatay (Kırıkhan, Iskenderun, Hassa and Yayladağı counties), Karabük (Safranbolu county Yukarıbucak and Ovacuma villages), Ankara (Ayaş, Nallıhan and Polatlı counties), Çukurova region (Adana-Cukurova, Mersin-Tarsus and Osmaniye-Kadirli counties) and Antalya (Korkuteli county) were investigated using gas chromatography-mass spectrometry (GC-MS/FID and GC-MS/MS) for identification and quantification of volatile compounds. Ultrasound-assisted extraction method using methanol:ethyl acetate solvent mixture was used to isolate the volatile components of saffron. This study revealed that the amounts of the volatile and bioactive compounds of saffron veried between different geographical locations. The most important bioactive compounds of saffron, safranal, crocin and crocetin, were also quantitatively analyzed in all saffron samples. The highest amount of safranal and crocin were observed in Hatay yayladağı saffron with 22532.97 mg kg-1 and 647.26 mg/kg, respectively. The highest amount of crocetin was obtained with 6.73 mg/kg in Ankara Ayaş saffron. While Hatay kırıkhan saffron contained the highest fraction of fatty acid content with 23.56%, the highest fraction of bioactive components was discovered in Karabük safranbolu ovacuma saffron with 90.84%. According to the obtained outcomes, the highest qualities saffron were determined to be observed in Hatay yayladağı and Karabük safranbolu ovacuma saffron, respectively.Öğe Hatay/Kırıkhan’da yetiştirilen safran (crocus sativus L.) stigmasının ekstraktının GC-MS analizi(2018) Göktürk, Ersen; Asil, HasanHatay/Kırıkhan’da yetiştirilen safran (Crocus sativus L.) stigmasının metanol/etil asetat karışımı ile ekstraksiyonu yapılmış ve safranın uçucu bileşenlerinin analizi GC-MS (gaz kromatografisi-kütle pektroskopisi) ile gerçekleştirilmiştir. Elde edilen sonuçlara göre Safran stigmasında değişik yapılarda fitokimyasalların bulunduğu gözlenmiştir. Bu bileşenlerin bazıları literatürden elde edilen verilere göre, biyoaktif özelliklere ve birçok farmakolojik etkiye sahiptirler.Öğe Horseradish Peroksidaz Nano Biyokatalizörü İle Hidrokinon’un Polimerleştirilmesi(2021) Göktürk, ErsenBu araştırmada, Fe2+ iyonlarının horseradish peroksidaz (HRP) enzimiyle oluşturduğu çiçek şekilli hibrit nano biyokatalizörün (HRP-Fe2+), hidrokinon’un polimerleşmesi üzerine etkisi incelenmiştir. Elde edilen sonuçlara göre; HRP-Fe2+ biyokatalizörü ve hidrojen peroksit (H2O2) başlatıcısı kullanılarak gerçekleştirilen polimerleşmeler, serbest HRP enziminin kullanıldığı koşullara kıyasla yüksek sıcaklıklarda oldukça yüksek katalitik kararlılık göstermiştir. Poly(hidrokinon), pH 7.4 tamponu içerisinde 60 oC sıcaklıkta ve ağırlıkça %5 oranında HRP-Fe2+ biyokatalizörü eklenmesiyle %44 verimle sentezlenmiştir. HRP-Fe2+ biyokatalizörü, serbest HRP enziminin denatüre olduğu 70 oC gibi yüksek sıcaklıklarda bile bozunmaya uğramadan katalitik aktivite göstermiştir. HRP-Fe2+ biyokatalizörünün ayrıca serbest HRP enzimine kıyasla az da olsa daha düşük katalitik aktivite gösterdiği gözlenmiştir. Bu iki katalizörle gerçekleştirilen polimerleşmelerde verimlerin birbirine yakın olduğu, ancak serbest HRP enzimi kullanılarak elde edilen polimerlerin HRP-Fe2+ kullanılarak elde edilen polimerlere kıyasla daha yüksek molekül ağırlığına sahip olduğu gözlenmiştir. Buradan da HRP-Fe2+ biyokatalizörünün katalitik aktivitesinin, serbest HRP enzimine kıyasla azaldığı sonucuna varılmıştır.Öğe Investigation of Peroxidase-Like Activity of Flower-Shaped Nanobiocatalyst from Viburnum Opulus L. Extract on the Polymerization Reactions(2024) Kalaycı, Berkant; Kaplan, Naime; Mirioğlu, Müge; Dadı, Şeyma; Ocsoy, Ismail; Göktürk, ErsenHere, we report the effects of peroxidase-mimicking activity of flower shaped hybrid nanobiocatalyst obtained from Viburnum-Opulus L. (Gilaburu) extract and Cu2+ ions on the polymerization of phenol and its derivatives (guaiacol and salicylic acid). The obtained nanoflowers exhibited quite high catalytic activity upon the polymerization of phenol and guaiacol. The yields and the number average molecular weights of the obtained polymers were significantly high. Due to solubility issue of salicylic acid in aqueous media, polymerization of salicylic acid resulted in very low yields. Free-horseradish peroxidase (HRP) enzyme is known to be losing its catalytic activity at 60 °C and above temperatures. However, the synthesized nanoflowers exhibited quite high catalytic activity even at 60 °C and above reaction temperatures. This provides notable benefits for reactions needed at high temperatures, and it is very important to use these kinds of nanobiocatalysts for both scientific studies and industrial applications.
