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Öğe Fabrication of Cu2ZnSnS4 (CZTS) nanofibers via electrospinning(AMER CHEMICAL SOC, 2014) Buyukbekar, Burak Zafer; Ozel, Faruk; Sakalak, Huseyin; Kus, Mahmut; Yavuz, Mustafa Selman[Abstract not Available]Öğe Facile synthesis of "green" gold nanocrystals using cynarin in an aqueous solution(ELSEVIER SCIENCE BV, 2014) Katircioglu, Zeynep; Sakalak, Huseyin; Ulasan, Mehmet; Goren, Ahmet Ceyhan; Yavuz, Mustafa SelmanHerein we describe a water-based protocol that generates Au nanoparticles (AuNPs) by mixing aqueous solutions of HAuCl4 and cynarin (a natural product extract from artichoke leaf). Based on the observations from H-1 NMR spectrum of AuNPs, a polyol oxidation mechanism by metal ions which eventually results in AuNPs formation, is proposed. Basically, the aromatic alcohol groups (1,2-benzenediol) of cynarin are oxidized to alpha-hydroxy ketone intermediate product, and then further oxidized to the vicinal diketone final product while the Au3+ ions are reduced to its atomic form (Au-0) which leads the generation of Au nanoparticles. This new protocol has also been employed to prepare multiply twinned Pd nanoparticles and Ag cubical aggregates. Due to exclusion of organic solvent, surfactant, or stabilizer for all these synthesis, this protocol may provide a simple, versatile, and environmentally benign route to fabricate noble-metal nanoparticles having various compositions and morphologies. (C) 2014 Elsevier B.V. All rights reserved.Öğe Gold nanoparticles immobilized on electrospun titanium dioxide nanofibers for catalytic reduction of 4-nitrophenol(WILEY-V C H VERLAG GMBH, 2017) Cavusoglu, Halit; Buyukbekar, Burak Zafer; Sakalak, Huseyin; Kohsakowski, SebastianThis study involves the preparation and catalytic properties of anatase titanium dioxide nanofibers (TiO2 NFs) supported gold nanoparticles (Au NPs) using a model reaction based on the reduction of 4-nitrophenol (NP) into 4-aminophenol (AP) by sodium borohydride (NaBH4). The fabrication of surfactant-free Au NPs was performed using pulsed laser ablation in liquid (PLAL) technique. The TiO2 NFs were fabricated by a combination of electrospinning and calcination process using a solution containing poly(vinyl pyrolidone)(PVP) and titanium isopropoxide. The adsorption efficiency of laser-generated surfactant-free Au NPs to TiO2 NF supports as a function of pH was analyzed. Our results show that the electrostatic interaction mainly controls the adsorption of the nanoparticles. Au NPs/TiO2 NFs composite exhibited good catalytic activity for the reduction of 4-NP to 4-AP. The unique combination of these materials leads to the development of highly efficient catalysts. Our heterostructured nanocatalysts possibly form an efficient path to fabricate various metal NP/metal-oxide supported catalysts. Thus the applications of PLAL-noble metal NPs can widely broaden.Öğe Influences of size, shape and surface chemistry of gold nanoparticles on dipeptide self-assembly(AMER CHEMICAL SOC, 2014) Erdogan, Hakan; Sakalak, Huseyin; Yavuz, Mustafa Selman; Demirel, Gokhan[Abstract not Available]Öğe Laser-Triggered Degelation Control of Gold Nanoparticle Embedded Peptide Organogels(AMER CHEMICAL SOC, 2013) Erdogan, Hakan; Sakalak, Huseyin; Yavuz, Mustafa S.; Demirel, GokhanFurther understanding of the interactions between nanoparticles (NPs) and biological molecules offers new possibilities in the applications of nanomedicine and nanodiagnostics. The properties of NPs, including size, shape, and surface functionality, play a decisive role in these interactions. Herein, we evaluated the influences of gold NPs (AuNPs) with different sizes (5-60 nm) and shapes (i.e., spherical, rod, and cage) on the self assembly of diphenylalanine (Phe-Phe) dipeptides. We found that the size of AuNPs smaller than 10 nm did not affect the self-assembly process of Phe-Phe, while bigger AuNPs (>10 nm) caused the formation of starlike peptide morphologies connected to one center. In the case of shape differences, nanorod and nanocage morphologies acted differently than spherical ones and caused the formation of densely packed, networklike dipeptide morphologies. In addition to these experiments, by combining photothermal properties of AuNPs with a Phe-Phe-based organogel having a thermo-responsive property, we demonstrated that the degelation process of AuNPs embedded organogels may be controlled by laser illumination. Complete degelation was achieved in about 10 min. We believe that such control may open the door to new opportunities for a number of applications, such as controlled release of drugs and tissue engineering.Öğe Measuring temperature change on photothermal Au nanorod and nanocage upon laser irradiation(AMER CHEMICAL SOC, 2015) Cavusoglu, Halit; Sakalak, Huseyin; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman[Abstract not Available]Öğe New method for measuring the temperature change of photothermal Au nanostructures using smart polymers(AMER CHEMICAL SOC, 2015) Cavusoglu, Halit; Sakalak, Huseyin; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman[Abstract not Available]Öğe Novel capsules for potential theranostics of obscure gastrointestinal bleedings(CHURCHILL LIVINGSTONE, 2016) Colak, Bayram; Sakalak, Huseyin; Cavusoglu, Halit; Yavuz, Mustafa SelmanObscure gastrointestinal (GI) bleeding is identified as persistent or repeated bleeding from the gastrointestinal tract which could not be defined by conventional gastrointestinal endoscopy and radiological examinations. These GI bleedings are assessed through invasive diagnostic and treatment methods including enteroscopy, angiography and endoscopy. In addition, video capsule endoscopy (VCE) is a non-invasive method used to determine the location of the bleeding, however, this does not provide any treatment. Despite of these successful but invasive methods, an effective non-invasive treatment is desperately needed. Herein, we prepare non-invasive theranostic capsules to cure obscure GI bleeding. An effective theranostic capsule containing endothelin as the targeting agent, thrombin-fibrinogen or fibrin as the treating agent, and fluorescein dye as the diagnostic tool is suggested. These theranostic capsules can be administered orally in a simple and non-invasive manner without a risk of complication. By using these novel capsules, one can diagnose obscure GI bleeding with having a possibility of curing. (C) 2016 Elsevier Ltd. All rights reserved.Öğe One-pot synthesis of biocompatible boronic acid-functionalized poly(methyl methacrylate) nanoparticles at sub-100 nm scale for glucose sensing(SPRINGER, 2014) Sakalak, Huseyin; Ulasan, Mehmet; Yavuz, Emine; Camli, Sevket Tolga; Yavuz, Mustafa SelmanPoly(methyl methacrylate) nanoparticles containing 4-vinylphenyl boronic acid were synthesized in one pot by surfactant-free emulsion polymerization. The nanoparticles were characterized by scanning electron microscopy and dynamic light scattering. Boron content in the nanoparticles was confirmed by electron-dispersive X-ray spectroscopy. In polymerization process, several co-monomer ratios were studied in order to obtain optimum nanoparticle size. Average hydrodynamic diameter and polydispersity index of nanoparticles versus variation of acetone percentage in the solvent mixture and total monomer concentration were investigated. The effect of boronic acid concentration in the monomer mixture on nanoparticle size and size distribution was also reported. Without further functionalization to the nanoparticles, the catechol dye, alizarin red S, was bound to boronic acid-containing nanoparticles. These nanoparticles behave as a nanosensor by which glucose or fructose can be easily detected. Dye-containing nanoparticles were undertaken displacement reaction by glucose or fructose. The glucose or fructose content was also monitored by UV-Visible spectrophotometer. Furthermore, cytotoxicity studies of boronic acid-carrying poly(methyl methacrylate) nanoparticles were carried out in 3T3 cells, which showed no toxicity effect on the cells.Öğe One-pot synthesis of sub-100 nm scale boronic acid functionalized nanoparticles for fluorescent diol sensing(AMER CHEMICAL SOC, 2014) Sakalak, Huseyin; Ulasan, Mehmet; Camli, Sevket Tolga; Yavuz, Mustafa Selman[Abstract not Available]
