Person: OKTAR, FAİK NÜZHET
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OKTAR
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FAİK NÜZHET
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Publication Metadata only 3D Printing of Gelatine/Alginate/beta-Tricalcium Phosphate Composite Constructs for Bone Tissue Engineering(WILEY-V C H VERLAG GMBH, 2019) OKTAR, FAİK NÜZHET; Kalkandelen, Cevriye; Ulag, Songul; Ozbek, Burak; Eroglu, Gunes O.; Ozerkan, Dilsad; Kuruca, Serap E.; Oktar, Faik N.; Sengor, Mustafa; Gunduz, OguzhanBone tissue engineering studies have brought three-dimensional scaffolds into focus that can provide tissue regeneration with designed porosity and strengthened structure. Current research has concentrated on the fabrication of natural and synthetic polymer-based complex structures that closely mimic biological tissues due to their superior biocompatibility and biodegradabilities. Gelatine/Sodium Alginate hydrogels reinforced with different concentrations of beta-Tricalcium Phosphate (TCP) (10, 13, and 15 wt.%) were studied to form 3D bone tissue. Physical, mechanical, chemical, morphological properties and biodegradability of the constructs were investigated. Furthermore, in vitro biological assay with human osteosarcoma cell line (SAOS-2) was performed to determine the biocompatibility of the constructs. It is found that cell viability rates for all constructs were increased and maximum cell viability rate was attained for 20%Gelatine/2%Alginate/10%TCP (wt.). The present work demonstrates that 3D printed Gelatine/Alginate/TCP constructs with porous structures are potential candidates for bone tissue engineering applications.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 Metadata only Glioblastoma cell adhesion properties through bacterial cellulose nanocrystals in polycaprolactone/gelatin electrospun nanofibers(ELSEVIER SCI LTD, 2020) YILMAZ, BETÜL; Unal, Semra; Arslan, Sema; Yilmaz, Betul Karademir; Kazan, Dilek; Oktar, Faik Nuzhet; Gunduz, OguzhanGlioblastoma (GBM), the most common and extremely lethal type of brain tumor, is resistant to treatment and shows high recurrence rates. In the last decades, it is indicated that standard two-dimensional (2D) cell culture is inadequate to improve new therapeutic strategies and drug development. Hence, well-mimicked three-dimensional (3D) tumor platforms are needed to bridge the gap between in vitro and in vivo cancer models. In this study, bacterial cellulose nano-crystal (BCNC) containing polycaprolactone (PCL) /gelatin (Gel) nanofibrous composite scaffolds were successfully fabricated by electrospinning for mimicking the extracellular matrix of GBM tumor. The fiber diameters in the nanofibrous matrix were increased with an increased concentration of BCNC. Moreover, fiber morphology changed from the smooth formation to the beaded formation by increasing the concentration of the BCNC suspension. In-vitro biocompatibilities of nanofibrous scaffolds were tested with U251 MG glioblastoma cells and improved cell adhesion and proliferation was compared with PCL/Gel. PCL/Gel/BCNC were found suitable for enhancing axon growth and elongation supporting communication between tumor cells and the microenvironment, triggering the process of tumor recurrence. Based on these results, PCL/Gel/BCNC composite scaffolds are a good candidate for biomimetic GBM tumor platform.Publication Metadata only Investigation of 3D-Printed Polycaprolactone-/Polyvinylpyrrolidone-Based Constructs(SAGE PUBLICATIONS INC) ŞAHİN, ALİ; Izgordu, Muhammet Sefa; Uzgur, Evren Isa; Ulag, Songul; Sahin, Ali; Yilmaz, Betul Karademir; Kilic, Beyhan; Ekren, Nazmi; Oktar, Faik Nuzhet; Gunduz, OguzhanThe aim of this study is to evaluate the mechanical and biological performance of cartilage-like constructs produced by 3D printing. During the investigation, poly(epsilon-caprolactone) (PCL) and polyvinylpyrrolidone (PVP) were used as a matrix polymer and low-molecular-weight chitosan (CS), hyaluronic acid (HA), and alginic acid sodium salt (SA) were integrated separately with the polymer matrix to fabricate the constructs. Thermal, mechanical, morphology, and chemical properties and swelling, degradation, and biocompatibility behaviors were evaluated in detail. With the addition of 3 fillers, the melting temperature of the matrix increased with the addition of fillers, and PCL/3wt.%PVP/1wt.%HA had the highest melting temperature value. Mechanical characterization results demonstrated that the printed PCL/3wt.%PVP/1wt.%CS displayed the highest compressive strength of around 9.51 MPa. The compressive strength difference between the PCL/3wt.%PVP and PCL/3wt.%PVP/1wt.%CS was 5.38 MPa. Biocompatibility properties of the constructs were tested by mitochondrial dehydrogenase activity, and in vitro studies showed that the PCL/3wt.%PVP/1wt.%HA composite construct had more cell viability than the other constructs by making use of the mesenchymal stem cell line.Publication Metadata only Production and characterization of electrospun fish sarcoplasmic protein based nanofibers(ELSEVIER SCI LTD, 2018) KAZAN, DİLEK; Sahin, Yesim M.; Su, Sena; Ozbek, Burak; Yucel, Sevil; Pinar, Orkun; Kazan, Dilek; Oktar, Faik N.; Ekren, Nazmi; Gunduz, OguzhanIn this study, poly (e-caprolactone) (PCL) and fish sarcoplasmic protein (FSP) (Mw < 200 kDa) composite nanofibers were fabricated by electrospinning technique. Solution properties such as density, viscosity, conductivity and surface tension were studied as a function of FSP content in the solution. The morphology, molecular interaction, degradation as well as thermal and tensile properties of PCL/FSP nanofibers were investigated. The results show that smooth and beadless PCL/FSP nanofibers with the diameters ranging from 120 +/- 29 nm to 139 +/- 41 nm were obtained. The average diameters decreased and the diameter distributions narrowed with the addition of optimum FSP amount. The characteristic picks of FSP and PCL were identified in the composite nanofibers by structural analyses. PCL/FSP nanofibers exhibited high degradation ability in comparison to electrospun pure PCL nancifibers. Moreover, the PCL/FSP nanofibers exhibit good mechanical properties (tensile strength of 5.55 MPa) with the additional FSP content. (C) 2017 Elsevier Ltd. All rights reserved.Publication Metadata only Drug Delivery Systems for Dental Applications(BENTHAM SCIENCE PUBL LTD, 2017) OKTAR, FAİK NÜZHET; Ficai, Denisa; Sandulescu, Mihai; Ficai, Anton; Andronescu, Ecaterina; Yetmez, Mehmet; Agrali, Omer B.; Elemek, Eser; Gunduz, Oguzhan; Sahin, Yesim M.; Oktar, Faik N.Inevitable caries formation and other tooth related diseases are one of the most common factors affecting human quality of life, as they are often followed by loss of teeth. Significant research efforts have been devoted to establishing control and preventive solutions. It is clearly known that fluoride is one of the promising chemical substances with anti-carious activity. The elimination of the microbial infection, especially the multispecies infections induced by aerobic and anaerobic bacteria, is a current challenge of the endodontic therapy. Using antibiotics or other active agents (from ions, nanoparticles to natural products) loaded in specific drug carrier systems seems to be ideal approach in treating and controlling dental diseases, even if, the drug delivery systems used in dental applications are less established comparing with other tissues/organs. Based on the importance of biomedical drug delivery systems the present study aims to give a brief review on the improvements of drug delivery systems for dental applications.Publication Open Access Electrospun Nanocomposite Materials, A Novel Synergy of Polyurethane and Bovine Derived Hydroxyapatite(IOP PUBLISHING LTD, 2017-04-21) OKTAR, FAİK NÜZHET; Bozkurt, Y.; Sahin, A.; Sunulu, A.; Aydogdu, M. O.; Altun, E.; Oktar, F. N.; Ekren, N.; Gunduz, O.; Tai, Y; Priyanka, SPolyurethane (PU) is a synthetic polymer that is used for construction of scaffold in tissue engineering applications in order to obtain desirable mechanical, physical and chemical properties like elasticity and durability. Bovine derived hydroxyapatite (BHAp) is a ceramic based natural polymer that is used as the most preferred implant material in orthopedics and dentistry due to their chemically and biologically similarity to the mineral phase found in the human bone structure. PU and bovine derived hydroxyapatite (BHAp) solutions with different concentrations were prepared with dissolving polyurethane and BHAp in Dimethylformamide (DMF) and Tetrahydrofuran (THF) solutions. Blended PU-BHAp solutions in different concentrations were used for electrospinning technique to create nanofiber scaffolds and new biocomposite material together. SEM, FTIR and physical analysis such as viscosity, electrical conductivity, density measurement and tensile strength measurement tests were carried out after production process.Publication Metadata only 3D bio-printing of levan/polycaprolactone/gelatin blends for bone tissue engineering: Characterization of the cellular behavior(PERGAMON-ELSEVIER SCIENCE LTD, 2019) İNAN, AHMET TALAT; Duymaz, Busra Tugce; Erdiler, Fatma Betul; Alan, Tugba; Aydogdu, Mehmet Onur; Inan, Ahmet Talat; Ekren, Nazmi; Uzun, Muhammet; Sahin, Yesim Muge; Bulus, Erdi; Oktar, Faik Nuzhet; Selvi, Sinem Selvin; ToksoyOner, Ebru; Kilic, Osman; Bostan, Muge Sennaroglu; Eroglu, Mehmet Sayip; Gunduz, OguzhanPoly(epsilon-caprolactone) (PCL), gelatin (GT) and different concentrations of low molecular weight Halomonas levan (HLh) were combined and examined to develop physical networks serving as tissue scaffolds to promote cell adhesion for biocompatibility. Three-dimensional bioprinting technique (3D bioprinting) was employed during manufacturing the test samples and their comprehensive characterization was performed to investigate the physicochemical properties and biocompatibility. Physical properties of the printing materials such as viscosity, surface tension, and density were measured to determine optimal parameters for 3D bioprinting. The scanning electron microscope (SEM) was used to observe the morphological structure of scaffolds. Fourier-Transform Infrared Spectroscopy (FT-IR) and differential scanning calorimetry (DSC) were used to identify the interactions between the components. In-vitro cell culture assays using standard human osteoblast (Hob) cells showed increased biocompatibility of the printing materials with increasing HLh content. Thus, the formulations including the HLh are expected to be a good candidate for the production of 3D printed materials.Publication Metadata only Production of the novel fibrous structure of poly(epsilon-caprolactone)/tri-calcium phosphate/hexagonal boron nitride composites for bone tissue engineering(AUSTRALIAN CERAMIC SOCIETY, 2018) OKTAR, FAİK NÜZHET; Ozbek, Burak; Erdogan, Barkin; Ekren, Nazmi; Oktar, Faik Nuzhet; Akyol, Sibel; Ben-Nissan, Besim; Sasmazel, Hilal Turkoglu; Kalkandelen, Cevriye; Mergen, Ayhan; Kuruca, Serap Erdem; Ozen, Gunes; Gunduz, OguzhanNanofibrous composites of the poly(epsilon-caprolactone) (PCL), tricalcium phosphate (TCP), and hexagonal boron nitride (h-BN) with different compositions were manufactured by using an economical and non-complicated method called electrospinning. Produced fibrous structures showed no bead formation and had a clean surface. Characterization of the composites showed that particles were successfully mixed with polymer phase. High cell activity of SaOS-2 cells on the composites was observed with SEM images. In addition, fibrous scaffolds are biocompatible with human bone tissue and are highly degradable.