Person: OKTAR, FAİK NÜZHET
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
OKTAR
First Name
FAİK NÜZHET
Name
6 results
Search Results
Now showing 1 - 6 of 6
Publication Open Access Synthesis and characterization of interpenetrating network (IPN) based levan-polyacrylamide hydrogels and their application in conservation of cultural heritage(2023-11-01) ÜNAL YILDIRIM, SEMRA; OKTAR, FAİK NÜZHET; GENÇ, SEVAL; TOKSOY ÖNER, EBRU; Özen Sağlam R., Ünal Yıldırım S., Oktar F. N., Genç S., Erdem G., Toksoy Öner E.In this study, an IPN based enzymatic levan-polyacrylamide hydrogel (EL-PA) was developed and characterized for its structural, morphological, rheological properties and swelling kinetics to underline hydrogel properties and its potential use in paper conservation. The addition of levan also led to changes in the viscoelastic behavior of the hydrogels, with the complex viscosity of EL-PA samples showing pronounced dependence on shear rate. The swelling and the overall surface area of the hydrogels were increased with the addition of levan into the polymer network. Source associated structural differences were found to be negligible such that both microbially produced linear and enzymatically produced branched forms of levan performed equally well. Solvent loaded hydrogels were then applied on an artifact, a 19th century book of Namık Kemal, and investigated using FTIR, SEM, XRD and colorimetric analysis. Old adhesive layers were successfully removed, and hydrogels showed good compatibility and ease of application. This study has shown that levan has improved hydrogel properties and levan based systems bear high potential in conservation science.Publication Open Access Marine-derived bioceramics for orthopedic, reconstructive and dental surgery applications(2022-11-01) OKTAR, FAİK NÜZHET; ÜNAL YILDIRIM, SEMRA; GÜNDÜZ, OĞUZHAN; EKREN, NAZMİ; ALTAN, ERAY; OKTAR F. N. , Unal S., GÜNDÜZ O., Ben Nissan B., Macha I. J. , Akyol S., Duta L., EKREN N., ALTAN E., YETMEZ M.Bioceramics are a fast-growing materials group, which are widely used in orthopedics, maxillofacial, dental, and reconstructive surgeries. They are produced using raw materials either from synthetic or natural sources. As naturally originated resources, the bones of sheep and cows are used after converting to calcium phosphates. Human-originated sources in the past were obtained from human cadaver bones, however now-a-days this has been discontinued. On the other hand, the \"golden standard\" in the reconstruction surgery has been using patients own bones, -i.e., autogenous bones, which heal better than other alternatives. Besides natural products, synthetic materials are produced from a range of inorganic raw and natural materials based on marine sources, such as corals, and other marine-derived materials (i.e., seashells, nacre). These are used to produce bioceramics and hence implants, devices, and bone grafts. Although during the last four decades a number of excellent books and book chapters have been published, no comprehensive review has been yet reported to cover the available marine materials and to indicate the related work and corresponding references to allow for both medical and ceramic scientists to access directly and open new avenues for further research on marine structures and their applications in orthopedic, maxillofacial, and reconstructive surgery areas. Hence, this review covers the general marine structures, their locations and availability in different countries and, current research on production methods of these unique structures that are difficult to fabricate synthetically. The authors are confident that this comprehensive review will be an excellent source not only for the ceramists, but also for the medical scientists.Publication Open Access An eco-friendly process to extract hydroxyapatite from sheep bones for regenerative medicine: Structural, morphologic and electrical studies(2023-05-01) GÜNDÜZ, OĞUZHAN; OKTAR, FAİK NÜZHET; Gavinho S. R., Bozdag M., KALKANDELEN C., Regadas J. S., Jakka S. K., GÜNDÜZ O., OKTAR F. N., Graça M. P. F.Hydroxyapatite (HA) promotes excellent bone regeneration in bone-tissue engineering, due to its similarity to bone mineral and its ability to connect to living tissues. These factors promote the osteointegration process. This process can be enhanced by the presence of electrical charges, stored in the HA. Furthermore, several ions can be added to the HA structure to promote specific biological responses, such as magnesium ions. The main objective of this work was to extract hydroxyapatite from sheep femur bones and to study their structural and electrical properties by adding different amounts of magnesium oxide. The thermal and structural characterizations were performed using DTA, XRD, density, Raman spectroscopy and FTIR analysis. The morphology was studied using SEM, and the electrical measurements were registered as a function of frequency and temperature. Results show that: (i) an increase of MgO amount indicates that the solubility of MgO is below 5%wt for heat treatments at 600 °C; (ii) the rise of MgO content increases the capacity for electrical charge storage; (iii) sheep hydroxyapatite presents itself as a natural source of hydroxyapatite, environmentally sustainable and low cost, and promising for applications in regenerative medicine.Publication Open Access Preparation and characterization of pure natural hydroxyapatite derived from seashells for controlled drug delivery(2022-09-01) OKTAR, FAİK NÜZHET; GÜNDÜZ, OĞUZHAN; BİLĞİÇ ALKAYA, DİLEK; AYAZ SEYHAN, SERAP; CESUR, SÜMEYYE; AYAZ SEYHAN S., Alkaya D., Cesur S., OKTAR F. N., GÜNDÜZ O.The marine species are specially used for the fabrication of bioceramic nano-powders with natural methods for their use in controlled drug delivery. However, there are only very limited studies regarding the production and synthesis of hydroxyapatite (HA)-based drug delivery systems from marine structures. In this study, poly (vinyl alcohol) (PVA) containing Rifampicin (RIF)-loaded Orange Spiny Oyster Seashell (Spondylus barbatus) hydroxyapatite (HA) composite is synthesized by an in situ ultrasound-assisted method. All samples were analyzed by X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, and Scanning electron microscope (SEM), respectively. The in vitro drug release tests of the obtained samples were performed in a phosphate-buffered medium (PBS) at 37 degrees C. Drug release was evaluated according to five varying kinetic models. In vitro RIF release from HA/PVA composite in phosphate buffer (pH 7.4) showed prolonged sustained drug release. From the drug release kinetic models, Higuchi and Korsmeyer-Peppas were found to be the best model for the three ratios based on the correlation coefficient. The diffusion component is less than 0.5, which indicates quasi-fickian diffusion. From the kinetic study results, the RIF-loaded marine phase composite has potential use in drug delivery applications as it shows positive sustained drug release behavior.Publication Open Access A novel strategy as a potential rapid therapy modality in the treatment of corneal ulcers: Fluconazole/vancomycin dual drug-loaded nanofibrous patches(2023-01-01) CESUR, SÜMEYYE; BİNGÖL ÖZAKPINAR, ÖZLEM; TINAZ, GÜLGÜN; OKTAR, FAİK NÜZHET; GÜNDÜZ, OĞUZHAN; CESUR S., Ilhan E., Pilavci E., Sulutas R. B., Gurboga M., BİNGÖL ÖZAKPINAR Ö., Kaya E., Heljak M., TINAZ G., OKTAR F. N., et al.Corneal ulcer, which is brought on by a breach in the epithelial barrier, is a dangerous infection of the avascular corneal stroma. New treatment strategies are needed, suppressing the aggressive nature of the disease and including a combination of different drugs. In this study, vancomycin (VAN) and fluconazole (FLU) dual-drug loaded dual-layered polyvinyl alcohol and gelatin (PVA/GEL) nanofibrous patches are produced by electrospinning. Scanning electron microscopy (SEM) images show smooth surfaces are obtained for both pure and drug-loaded nanofibrous patches. The tensile test results report that loading the FLU and VAN separately into the PVA/GEL patches decrease both the tensile strength and elongation at break and it is further reduced when combining two drug-loaded layers in one patch. According to drug release results, the FLU and VAN-loaded nanofibrous patches show a controlled release profile extending up to 96 h. Moreover, PVA/GEL/FLU, PVA/GEL/VAN, and PVA/GEL/FLU/VAN nanofibrous patches display significant antimicrobial activity against Candida albicans and Staphylococcus aureus. SEM, 4\"-6diamidynofenyloindol (DAPI) staining, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay show that PVA/FLU and PVA/GEL/FLU/VAN nanofibrous patches have a superior effect on NIH3T3 cell spreading and proliferation. The novelty of this study lays in the development of a potential dual drug rapid treatment for corneal ulcers of aggressive nature.Publication Open Access Effects of temperature and pH on the synthesis of nanohydroxyapatite powders by chemical precipitation(2023-01-01) ALTAN, ERAY; OKTAR, FAİK NÜZHET; GÜNDÜZ, OĞUZHAN; Mahmutoglu G., Topsakal A., ALTAN E., KUŞKONMAZ N., DAĞLILAR S., OKTAR F. N., Erdemir G., Kuruca S. E., AKYOL S., GÜNDÜZ O., et al.Bone tissue engineering is based on a comprehensive understanding of bone structure, bone mechanics, and biology. In order to create nanostructured hydroxyapatite powders with customized properties, many synthesis strategies such as wet chemical precipitation, sol-gel, hydrothermal, and biomimetic approaches have been intensively researched through the years. Calcium phosphate (CaP)-based ceramic nanoparticles, including hydroxyapatite (HAp), were synthesized by the chemical precipitation technique at pH ranges of 7 to 11 and different calcination temperatures of 600 to 1100 °C. The synthesized powders were characterized by several techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), energy dispersive X-ray analysis (EDX), and in vitro cell culture assays. The particle size analysis and zeta potential of these powders were also carried out using the dynamic light scattering (DLS) and laser Doppler electrophoresis methods. The results showed that the pH levels of 9 to 11 range and calcination temperatures of 600 to 800 °C were adequate for appropriate nanohydroxyapatite powder production using this method. The particle size of the nanohydroxyapatite was approximately 55 nm, although they were agglomerated after calcination. The biocompatibility tests demonstrated that these nanohydroxyapatite (nHAp) powders produced have appropriate cytocompatibility and can be used for bone graft production and other biomedical applications.