Browsing by Author "Çulha, Mustafa"

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Maltose Functionalized Magnetic Core/Shell Fe3O4@Au Nanoparticles for An Efficient L-Asparaginase Immobilization
(International Journal of Biological Macromolecules, 2020) Tarhan, Tuba; Ulu, Ahmet; Sariçam, Melike; Çulha, Mustafa; Ates, Burhan; Department of Medical Services and Techniques / Tıbbi Hizmetler ve Teknikleri Bölümü
In this study, maltose-functionalized magnetic core/shell nanoparticles (Fe3O4@Au NPs) as a promising carrier matrix for a simple and effective immobilization of L-asparaginase (L ASNase) were prepared and characterized using imaging techniques including atomic force microscopy (AFM) and transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The results indicate that the NPs are monodispersed with an average diameter of 10 nm and magnetization of 9.0 emu g-1. Under the optimal conditions, 77.2 ± 2.3% of the total L-ASNase was immobilized. It was found that the acid-base tolerance and thermal stability of immobilized L-ASNase were significantly improved in comparison to the free form of the enzyme in solution. For instance, while only 10% of the immobilized enzyme was lost its activity, the free form was lost its activity more than 50% after 3 h incubation at 55 oC. After 13 times recycling, the immobilized L-ASNase retained about 50% of its initial activity. Moreover, the free and immobilized L-ASNase maintained their initial activities about 25 and 64% after 28 days storage at 25 °C, respectively. Km value of immobilized L-ASNase decreased to 1.59 from 2.95 mM as an indication of increased enzyme affinity for the substrate. The results of this study suggest that the maltose-coated magnetic nanoparticles are excellent nanovehicles to carry enzymes for a range of industrial applications.
Citation - WoS: 6
Citation - Scopus: 6
Synthesis and Characterization of Bionanomaterials and Evaluation of Their Antioxidant, Antibacterial, and DNA Cleavage Activities
(Chemistry Select, 2021) Tarhan, Tuba; Dündar, Abdurrahman; Okumuş, Veysi; Çulha, Mustafa; Department of Medical Services and Techniques / Tıbbi Hizmetler ve Teknikleri Bölümü
In this study, the hexagonal boron nitride (hBN) (1), poly-levodopa (P-L(DP) (2), P-L(DP) coated hBN (hBN@P(L-DP)) (3), and silver nanoparticles (AgNPs) decorated hBN@P(L-DP) (hBN@P(L-DP)-AgNPs) (4) were synthesized and characterized by multiple spectroscopic techniques. Additionally, their biological properties such as antioxidant, antibacterial, and DNA cleavage activities were determined. It is worth noting that, products 3 and 4 were newly synthesized structures. The antioxidant activities of all the nanomaterials 1, 2, 3, and 4 nanomaterials were investigated using some tests such as DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging and reducing power ability. Among the synthesized nanomaterials, product 2 exhibited the highest radical scavenging (64.8±1.94 %) and reducing power activity (0.61±0.017) at a concentration of 200 mg L−1. Product 4 was determined to have antibacterial activity against all three Gram-positive and three Gram-negative test bacteria. In addition, all the nanomaterials were tested for cleavage activity using pBR 322 plasmid DNA, as a result of which it was determined that only product 4 showed the ability of cleavage from both chains of DNA.
Citation - WoS: 12
Citation - Scopus: 15
Synthesis and characterization of silver nanoparticles decorated polydopamine coated hexagonal boron nitride and its effect on wound healing
(Journal of Trace Elements in Medicine and Biology, 2021) Tarhan, Tuba; Şen, Özlem; Emanet Ciofani, Melis; Yılmaz, Deniz; Çulha, Mustafa; Department of Medical Services and Techniques / Tıbbi Hizmetler ve Teknikleri Bölümü
Background: Wound healing is an essential physiological process involving many cell types and their products acting in a marvellous harmony to repair damaged tissues. During the healing process, cellular proliferation and extracellular matrix remodelling stages could be interrupted by undesired factors including microorganisms and altered metabolic activities. In such a case, the process requires some external stimulants to accelerate or remediate the healing stages. Methods: In this study, we report a multifunctional wound healing stimulating agent. In this context, hexagonal boron nitride (hBN) nanoparticles, silver nanoparticles (AgNPs) and polydopamine(pdopa) were used through mussel-inspired chemistry of dopamine to obtain pdopa coated hBN (hBN@pdopa) and AgNPs decorated hBN@pdopa (hBN@pdopa-AgNPs). These two nanostructures were investigated to observe stages of healing. Results: AgNPs were chosen for inflammation reduction and hBN for induced cell proliferation and migration. In in vitro experiments, firstly, high cellular uptake capacity and biocompatibility of hBN@pdopa and hBN@pdopa-AgNPs were evaluated. They were also tested for their reaction against increased concentration of reactive oxygen species (ROS) in injured cells. Finally, their effect on cellular migration, intracellular tube formation and F-actin organization were monitored by light and confocal microscopy, respectively. Conclusion: The results clearly indicate that the hBN@pdopa-AgNPs significantly decrease ROS production, promote wound closure, and reorganize tube formation in cells.