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Öğe Antenna-type radiofrequency generator in nanoparticle-mediated hyperthermia(Royal Soc Chemistry, 2016) Nasseri, B.; Yilmaz, M.; Turk, M.; Kocum, I. C.; Piskin, E.Induction of hyperthermia using nanoparticles with specific magnetic, electrical, acoustic, optical or thermal properties is a potential alternative to conventional thermal ablation in cancer therapy. In this study, for the first time we employed an antenna-type radiofrequency (RF) generator as the energy source and as a proof of concept the effects of nanoparticles of varying structures and sizes, such as super-paramagnetic iron oxide nanoparticles (SPIONs), gold-coated superparamagnetic iron oxide nanoparticles (Au@SPIONs), spherical gold nanoparticles (AuNPs), and gold nanorods (AuNRs) on RF hyperthermia were examined to determine hyperthermia efficiency of the antenna-type RF generator. In preliminary experiments, RF was applied at varying powers to various nanoparticle solutions. In all cases, temperature rises due to exposure of RF radiation to nanoparticles were captured by using an infrared thermal camera. This procedure was applied to in vitro tests of fibroblast (L-929) and breast cancer (MCF-7) cell lines. Cell viability, apoptosis and necrosis were evaluated in both cell lines to comprehensively determine cell toxicity. Due to their particle size and chemical nature, SPIONs, in the case of highest RF power and nanoparticle concentration, resulted in the lowest cell viability and highest levels of apoptosis and necrosis.Öğe Auricular cartilage repair using cryogel scaffolds loaded with BMP-7-expressing primary chondrocytes(Wiley, 2013) Odabas, S.; Feichtinger, G. A.; Korkusuz, P.; Inci, I.; Bilgic, E.; Yar, A. S.; Piskin, E.The loss of cartilage tissue due to trauma, tumour surgery or congenital defects, such as microtia and anotia, is one of the major concerns in head and neck surgery. Recently tissue-engineering approaches, including gene delivery, have been proposed for the regeneration of cartilage tissue. In this study, primary chondrocytes were genetically modified with plasmid-encoding bone morphogenetic protein-7 (BMP-7) via the commercially available non-viral Turbofect vector, with the aim of bringing ex vivo transfected chondrocytes to resynthesize BMP-7 in vitro as they would in vivo. Genetically modified cells were implanted into gelatin-oxidized dextran scaffolds and cartilage tissue formation was investigated in 15x15mm auricular cartilage defects in vivo in 48 New Zealand (NZ) white rabbits for 4months. The results were evaluated via histology and early gene expression. Early gene expression results indicated a strong effect of exogenous BMP-7 on matrix synthesis and chondrocyte growth. In addition, histological analysis results exhibited significantly better cartilage healing with BMP-7-modified (transfected) cells than in the non-modified (non-transfected) group and as well as the control. Copyright (c) 2012 John Wiley & Sons, Ltd.Öğe Cryogel scaffolds with stem cells for bone tissue engineering: an animal model(Mary Ann Liebert Inc, 2008) Boelgen, N.; Vargel, I.; Cavusoglu, T.; Korkusuz, P.; Guezel, E.; Piskin, E.…Öğe Electrospun spiral-wounded polycaprolactone scaffolds with or without stem cells for cranial bone defects: an animal model(Mary Ann Liebert Inc, 2008) Isoglu, I. A.; Bolgen, N.; Vargel, I.; Cavusoglu, T.; Korkusuz, P.; Guzel, E.; Piskin, E.…Öğe Filling cranial defects in rats: 6 months animal study(Mary Ann Liebert Inc, 2008) Aydin, H. M.; Vargel, I.; Cavusoglu, T.; Korkusuz, P.; Guzel, E.; Piskin, E.[Abstract No tAvailable]Öğe The interaction of fibroblast and endothelial cells with electrospun nanofibrous Nap-FFGRGD reinforced pcl peripheral nerve regeneration conduits(Wiley-Blackwell, 2014) Polat, E.; Meifeng, Z.; Kong, D.; Turk, M.; Piskin, E.…Öğe Lactide-PEG cryostructures with stem cells as tissue engineering scaffolds in reconstruction of cranial bone defects in rat model(Mary Ann Liebert Inc, 2008) Egri, S.; Vargel, I.; Cavusoglu, T.; Korkusuz, P.; Guzel, E.; Uckan, D.; Piskin, E.…Öğe Novel biodegradable cryogels made of(Mary Ann Liebert Inc, 2007) Egri, S.; Vargel, I.; Korkusuz, P.; Plieva, F.; Galaev, I.; Piskin, E.[Abstract No tAvailable]Öğe Simvastatin releasing novel PCL scaffolds in rat cranium defects(Mary Ann Liebert Inc, 2007) Piskin, E.; Isoglu, A.; Bolgen, N.; Griffiths, S.; Vargel, İ.; Cavusoglu, T.; Cartmell, S.…Öğe Smart and cationic poly(NIPA)/PEI block copolymers as non-viral vectors: in vitro and in vivo transfection studies(Wiley-Blackwell, 2007) Türk, M.; Dinçer, S.; Piskin, E.In this study, in vitro and in vivo transfection of temperature-sensitive, polycationic poly(N-isopropylacrylamide) and polyethyleneimine copolymers (poly(NIPA)/PE125L) were performed. Copolymer and copolymer-plasmid DNA (pDNA) complexes were positively charged as +7.6 and +12.8, respectively. Gel retardation assay confirmed good complex formation and release of plasmid DNA in response to temperature and pH. Cytotoxicity tests showed at least 80% smooth muscle cell (SMC) viability. The uptake of the complexes by SMCs was quite high; however, the best gene expression efficiency achieved with the copolymeric vectors was about 30% with the complex prepared with a polymer: plasmid ratio of 6. Gene expression efficiency was enhanced up to 50% by changing the temperature from 37 degrees C to 28 degrees C. Preliminary in vivo studies were performed above and below lower critical solution temperature (LCST) in lung, heart, liver, kidney, muscle and also subcutaneously in 5 week-old mice. The gene expression ratio was higher in lung, tibial muscle and subcutaneously than in other tissues (heart, liver and kidney) above LCST. Then, temperature decrease caused an increase in the amount of gene expression in tibial muscle and subcutaneously, revealing the contribution of temperature-sensitivity on DNA release and gene expression. Copyright (c) 2007 John Wiley & Sons, Ltd.Öğe Synthesis and characterization of poly(glycerol-co-sebacate-co-epsilon-caprolactone) elastomers(Wiley-Blackwell, 2016) Aydin, H. M.; Salimi, K.; Yilmaz, M.; Turk, M.; Rzayev, Z. M. O.; Piskin, E.In this study, poly(glycerol-co-sebacate-co-epsilon-caprolactone) (PGSCL) elastomers were synthesized for the first time from the respective monomers. The structural analysis of PGSCL elastomers by nuclear magnetic resonance (H-1-NMR) and Fourier transform infrared spectroscopy (FTIR) revealed that the elastomers have a high number of hydrogen bonds and crosslinks. X-ray diffraction (XRD) and thermal analysis indicated an amorphous state. Differential scanning calorimetry (DSC) analysis showed that the elastomers has a glass transition temperature (T-g) of -36.96 degrees C. The Young's modulus and compression strength values were calculated as 46.08MPa and 3.192MPa, respectively. Calculations based on acid number and end groups analysis revealed a number average molecular weight of 148.15kDa. Even though the foaming studies conducted by using supercritical CO2 resulted in a porous structure; the obtained morphology tended to disappear after 48h, leaving small cracks on the surface. This phenomenon was interpreted as an indication of self-healing due to the high number of hydrogen bonds. The PGSCL elastomers synthesized in this study are flexible, robust to compression forces and have self-healing capacity. Thanks to good biocompatibility and poor cell-adhesion properties, the elastomers may find diverse applications where a postoperative adhesion barrier is required. Copyright (c) 2013 John Wiley & Sons, Ltd.
