Browsing by Author "Piskin, Erhan"

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Citation - WoS: 8
Citation - Scopus: 11
Stem Cells Combined 3D Electrospun Nanofibrous and Macrochannelled Matrices: A Preliminary Approach in Repair of Rat Cranial Bones
(Taylor & Francis Ltd, 2019) Isoglu, Ismail Alper; Bolgen, Nimet; Korkusuz, Petek; Vargel, Ibrahim; Celik, Hakan Hamdi; Kilic, Emine; Piskin, Erhan
Repair of cranial bone defects is an important problem in the clinical area. The use of scaffolds combined with stem cells has become a focus in the reconstruction of critical-sized bone defects. Electrospinning became a very attracting method in the preparation of tissue engineering scaffolds in the last decade, due to the unique nanofibrous structure of the electrospun matrices. However, they have a limitation for three dimensional (3D) applications, due to their two-dimensional structure and pore size which is smaller than a cellular diameter which cannot allow cell migration within the structure. In this study, electrospun poly(epsilon-caprolactone) (PCL) membranes were spirally wounded to prepare 3D matrices composed of nanofibers and macrochannels. Mesenchymal stromal/stem cells were injected inside the scaffolds after the constructs were implanted in the cranial bone defects in rats. New bone formation, vascularisation and intramembranous ossification of the critical size calvarial defect were accelerated by using mesenchymal stem cells combined 3D spiral-wounded electrospun matrices.
Citation - WoS: 25
Citation - Scopus: 25
Microwave-Assisted Green Approach for Graft Copolymerization of L-Lactic Acid Onto Starch
(Wiley, 2016) Salimi, Kouroush; Topuzogullari, Murat; Dincer, Sevil; Aydin, Halil Murat; Piskin, Erhan
Poly l-lactic acid grafted starch (St-g-PLA) copolymers were directly synthesized under microwave irradiation by using sodium hydroxide (NaOH) and stannous 2-ethyl hexanoate acting as a catalyst, without the use of toxic solvents. The product were characterized by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (C-13 CP/MAS NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA-DTG). SEM analysis indicated that microwave heating had a considerable effect on the interfacial adhesion between PLA and starch. Thermogravimetric analysis (TGA-DTG) revealed that copolymers exhibited better thermal stability. Maximum PLA grafting was achieved with the following reaction conditions: 450W microwave power, monomer ratio of 1:5 and 0.4M of NaOH. This study demonstrates that it is possible to obtain St-g-PLA copolymers with better processing characteristics and smaller sizes via microwave-assisted synthesis. The applied procedure is an interesting green synthesis method for the production of biodegradable materials used in a diverse range of applications. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42937.