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  • Küçük Resim
    Öğe
    Immobilization of Alpha-Amylase onto Ni2+ Attached Carbon Felt: Investigation of Kinetic Parameters from Potato Wastewater
    (Wiley, 2023) Acet, Ömür; İnanan, Tülden; Öndül Koç, Eda; Sert, Buse; Önal Acet, Burcu; Odabaşı, Mehmet; Ocakoğlu, Kasım; Dizge, Nadir
    α-amylase is an important enzyme for textile, food, paper, and the pharmaceutical industrial areas. In this study, Ni2+ attached carbon felt structures with nitrogen active site (Ni2+-N-ACF) are produced. The surface morphologies of the N-ACF and Ni2+-N-ACF are investigated by means of scanning electron microscopy (SEM) analysis. Ni2+ ions binding on the N-ACFs are determined by energy dispersive X-ray (EDX) analysis and a graphite furnace atomic absorption spectrometer (AAS). The effect of pH, ionic strength, initial α-amylase concentration, and temperature parameters is investigated for α-amylase immobilization on Ni2+-N-ACF structures. In addition, pH and temperature effect on the activities of the free and the immobilized amylase, kinetic parameters, storage, and operational stabilities are made. Lastly, starch degradation in potato waste water is tested on Ni2+-N-ACF. The obtained results show that α-amylase immobilized Ni2+-N-ACF can be used for starch degradation on an industrial scale.
  • Küçük Resim
    Öğe
    Innovative approach against cancer: Thymoquinone-loaded PHEMA-based magnetic nanoparticles and their effects on MCF-7 breast cancer
    (Elsevier, 2024) Yıldırım, Metin; Acet, Ömür; Önal Acet, Burcu; Karakoç, Veyis; Odabaşı, Mehmet
    Breast cancer is most common cancer among women in the World. Thymoquinone (TQ) exhibits a wide range of biological activities such as anticancer, antidiabetic, antimicrobial, analgesic, antioxidant, and anti-inflammatory effects. However, its effectiveness in cancer treatment is hindered by its poor bioavailability, attributed to its limited solubility in water. Hence, novel strategies are required to enhance the bioavailability of TQ, which possesses remarkable anticancer characteristics. The aim of this study is to prepare pHEMA-based magnetic nanoparticles carrying TQ (TQ-MNPs) to improve bioavailability, and therapeutic efficacy against breast cancer. For this purpose, TQ-MNPs were synthesized and characterized with Fourier transform infrared spectrophotometer (FTIR), scanning electron microscopy (SEM), dynamic light scattering (DLS), magnetic field using a vibrating sample magnetometer (VSM). The loading capabilities of synthesized magentic nanostructures were evaluated, and release investigations were conducted under experimental conditions that mimic the cellular environment. The findings of the studies indicated that the TQ carrying capacity of MNPs was deemed satisfactory, and the release efficiency was adequate. MNPs and TQ-MNPs showed biocompatibility against HDFa cells. TQ-MNPs showed stronger anti-proliferative activity against MCF-7 breast cancer cells compared to free TQ (p < 0.05). TQ-MNPs induced apoptosis in MCF-7 breast cancer cells.
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    Öğe
    A New Design to Enhance the Enzyme Activities: Investigation of L-Asparaginase Catalytic Performance by IMAC Effect on g-C3N4 Nanolayers
    (Springer Link, 2024) Sert, Buse; Acet, Ömür; Noma, Samir Abbas Ali; Osman, Bilgen; Odabaşı, Mehmet; Ocakoğlu, Kasım
    Recently, graphite carbon nitride (g-C3N4) has come to the fore as a new material with its carbon-based two-dimensional structure, simple preparation procedure, and excellent physicochemical stability properties. This study aims to investigate the activity and kinetic studies of the L-asparaginase enzyme via immobilized metal ion affinity chromatography (IMAC) process of g-C3N4 nanolayers. Firstly, g-C3N4 nanolayers were synthetized and Ni2+ ions were binded their surfaces. The synthesized samples were investigated by SEM, ICP-MS, XRD, and FTIR. The highest L-ASNase adsorption on Ni2+-g-C3N4 nanostructures was 444.1 mg/g, at 3 mg/mL L-ASNase concentration. Optimal medium conditions for L-ASNase adsorption occurred at pH 8.0 and 25 °C. The immobilized enzyme showed improved stability relating to the soluble enzyme in extreme situations. On the other hand, the storage stability and reusability of the immobilized enzyme were found to be approximately 64 and 53% of the original activity after 29 days at room temperature and 10 cycles, respectively. From the Michaelis–Menten constants Km and Vmax, both of them decreased after immobilization compare to the free one. The obtained outcomes showed that the g-C3N4 is a suitable matrix for L-asparaginase immobilization with ideal catalytic efficiency and improved stability.