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Öğe Biocompatible hydrogels: synthesis, swelling property and solvent effect on gelation(Selçuk Üniversitesi Mühendislik Fakültesi, 2013) Ulaşan, Mehmet; Çengeloğlu, Yunus; Yavuz, Mustafa SelmanBiocompatible hydrogels have an increasing interest in recent years. Poly (2-hydroxyethyl methacrylate, PHEMA) is widely studied with its biocompatible property. In this study, we have shown the gelation conditions to produce PHEMA hydrogels which have an excellent hydrogel property. Since dissolution forces by solvents are so important in gelation process, we studied the effect of solvent combination of acetone and water mixture in detail. As a result of investigation, the available acetonewater ratio limits were stated in order to obtain PHEMA hydrogels. The swelling property of PHEMA hydrogel was also shown. In our study, PHEMA samples imbibe water as much as five times of their own weight.Öğe Biocompatible thermoresponsive PEGMA nanoparticles crosslinked with cleavable disulfide based crosslinker for dual drug release(AMER CHEMICAL SOC, 2014) Ulasan, Mehmet; Yavuz, Emine; Bagriacik, Emin Umit; Cengeloglu, Yunus; Yavuz, Mustafa Selman[Abstract not Available]Öğe Biocompatible thermoresponsive PEGMA nanoparticles crosslinked with cleavable disulfide-based crosslinker for dual drug release(WILEY, 2015) Ulasan, Mehmet; Yavuz, Emine; Bagriacik, Emin Umit; Cengeloglu, Yunus; Yavuz, Mustafa SelmanSmart materials have been attracting much attention because of their stimuli responsive nature. We have synthesized biocompatible thermoresponsive crosslinked poly(ethylene glycol) methyl ether methacrylate (PEGMA)-co-vinyl pyrrolidone nanoparticles (PEGMA NPs) using disulfide-based crosslinker by surfactant-free emulsion polymerization method. Particle characterization studies were carried out by dynamic light scattering, and scanning electron microscopy. Polymerization kinetics, effect of crosslinker and initiator concentrations on both average hydrodynamic diameter and polydispersity index were investigated. Hydrodynamic diameters of thermoresponsive PEGMA NPs were decreased from 210 nm to 90 nm upon heating over the lowest critical solution temperature (LCST). Disulfide crosslinked PEGMA NPs were demonstrated as a dual delivery system. Rhodamine B, a model of small-sized drug molecule, and poly(ethylene glycol) (PEG)-alizarin yellow, a model of large drug molecule, were loaded into PEGMA NPs where LCST of these NPs was tuned to 37 degrees C, the body temperature. The rhodamine B was released from PEGMA NPs upon heating to 39 degrees C. Then, PEG-alizarin content was released by subsequent degradation of nanoparticles using dithiothreitol (DTT), which reduces disulfide bonds to thiols. Furthermore, cytotoxicity studies of PEGMA NPs were carried out in 3T3 cells, which resulted in no toxic effect on the cells. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 243-251, 2015.Öğe CO2 capture by sulfur-bridged nanoporous covalent organic polymers(AMER CHEMICAL SOC, 2016) Atas, Mehmet Sahin; Yavuz, Mustafa Selman[Abstract not Available]Öğe Combining 3-D plasmonic gold nanorod arrays with colloidal nanoparticles as a versatile concept for reliable, sensitive, and selective molecular detection by SERS(ROYAL SOC CHEMISTRY, 2014) Yilmaz, Mehmet; Senlik, Erhan; Biskin, Erhan; Yavuz, Mustafa Selman; Tamer, Ugur; Demirel, GokhanThe detection of molecules at an ultralow level by Surface-Enhanced Raman Spectroscopy (SERS) has recently attracted enormous interest for various applications especially in biological, medical, and environmental fields. Despite the significant progress, SERS systems are still facing challenges for practical applications related to their sensitivity, reliability, and selectivity. To overcome these limitations, in this study, we have proposed a simple yet facile concept by combining 3-D anisotropic gold nanorod arrays with colloidal gold nanoparticles having different shapes for highly reliable, selective, and sensitive detection of some hazardous chemical and biological warfare agents in trace amounts through SERS. The gold nanorod arrays were created on the BK7 glass slides or silicon wafer surfaces via the oblique angle deposition (OAD) technique without using any template material or lithography technique and their surface densities were adjusted by manipulating the deposition angle (a). It is found that gold nanorod arrays fabricated at alpha = 10 degrees exhibited the highest SERS enhancement in the absence of colloidal gold nanoparticles. Synergetic enhancement was obviously observed in SERS signals when combining gold nanorod arrays with colloidal gold nanoparticles having different shapes (i.e., spherical, rod, and cage). Due to their ability to produce localized surface plasmons (LSPs) in transverse and longitudinal directions, utilization of colloidal gold nanorods as a synergetic agent led to an increase in the enhancement factor by about tenfold compared to plain gold nanorod arrays. Moreover, we have tested our approach to detect some chemical and biological toxins namely dipicolinic acid (DIP), methyl parathion (MP), and diethyl phosphoramidate (DP). For all toxins, Raman spectra with high signal-to-noise ratios and reproducibility were successfully obtained over a broad concentration range (5 ppm-10 ppb). Our results suggest that the slightly tangled and closely-packed anisotropic gold nanorod arrays reinforced by the gold nanoparticles may serve as an ideal SERS substrate to detect any analyte in trace amounts.Öğe A comparative study on fabrication of Cu2ZnSnS4 (CZTS) nanofibers using acetate and chloride metal precursors(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2015) Buyukbekar, Burak Zafer; Ozel, Faruk; Sakalak, Huseyin; Cavusoglu, Halit; Ersoz, Mustafa; Kus, Mahmut; Yavuz, Mustafa SelmanThis study reports, for the first time, the fabrication of electrospun Cu2ZnSnS4 (CZTS) nanofibers using metal acetate precursors. Viscous poly(vinyl pyrrolidone) (PVP) solution containing acetate or chloride salts of copper, zinc, and tin was electrospun onto a conductive substrate. The PVP nanofibers that have a mixture of metal salts were annealed at elevated temperatures. After calcination, these nanofibers were treated with the sulfur source and then annealed again in order to generate CZTS nanofibers. The CZTS nanofibers generated from acetate and chloride salts were characterized and compared. Belt-like and wire-like nanofibers were obtained when using metal acetate and chloride precursors, respectively.Öğe Discriminating a Single Nucleotide Difference for Enhanced miRNA Detection Using Tunable Graphene and Oligonucleotide Nanodevices(AMER CHEMICAL SOC, 2015) Robertson, Neil M.; Hizir, Mustafa Salih; Balcioglu, Mustafa; Wang, Rui; Yavuz, Mustafa Selman; Yumak, Hasan; Ozturk, BirolIn this study we have reported our efforts to address some of the challenges in the detection of miRNAs using water-soluble graphene oxide and DNA nanoassemblies. Purposefully inserting mismatches at specific positions in our DNA (probe) strands shows increasing specificity against our target miRNA, miR-10b, over miR-10a which varies by only a single nucleotide. This increased specificity came at a loss of signal intensity within the system, but we demonstrated that this could be addressed with the use of DNase I, an endonuclease capable of cleaving the DNA strands of the RNA/ DNA heteroduplex and recycling the RNA target to hybridize to another probe strand. As we previously demonstrated, this enzymatic signal also comes with an inherent activity of the enzyme on the surface-adsorbed probe strands. To remove this activity of DNase I and the steady nonspecific increase in the fluorescence signal without compromising the recovered signal, we attached a thermoresponsive PEGMA polymer (poly(ethylene glycol) methyl ether methacrylate) to nGO. This smart polymer is able to shield the probes adsorbed on the nGO surface from the DNase I activity and is capable of tuning the detection capacity of the nGO nanoassembly with a thermoswitch at 39 degrees C. By utilizing probes with multiple mismatches, DNase I cleavage of the DNA probe strands, and the attachment of PEGMA polymers to graphene oxide to block undesired DNase I activity, we were able to detect miR-10b from liquid biopsy mimics and breast cancer cell lines. Overall we have reported our efforts to improve the specificity, increase the sensitivity, and eliminate the undesired enzymatic activity of DNase Ion surface-adsorbed probes for miR-10b detection using water-soluble graphene nanodevices. Even though we have demonstrated only the discrimination of miR-10b from miR-10a, our approach can be extended to other short RNA molecules which differ by a single nucleotide.Öğe Disulfide-linked triazine based porous polymer networks for CO2 capture(AMER CHEMICAL SOC, 2016) Goren, Ekrem; Cavusoglu, Halit; Yavuz, Mustafa Selman[Abstract not Available]Öğe Efficient CO2 adsorption by disulfide-linked covalent organic polymers(AMER CHEMICAL SOC, 2016) Goren, Ekrem; Cavusoglu, Halit; Yavuz, Mustafa Selman[Abstract not Available]Öğe Efficient removal of toxic cationic dyes from wastewater using disulfide-linked porous polymer networks(AMER CHEMICAL SOC, 2015) Atas, Mehmet Sahin; Cavusoglu, Halit; Ozkaya, Aysenur; Yavuz, Mustafa Selman[Abstract not Available]Öğe Fabrication and application of magnetic nanoparticles using red mud(AMER CHEMICAL SOC, 2016) Katircioglu, Zeynep; Dursun, Sami; Yavuz, Mustafa Selman[Abstract not Available]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 Fabrication of magnetic nanoparticles from red mud for arsenic removal(AMER CHEMICAL SOC, 2016) Katircioglu, Zeynep; Dursun, Sami; Yavuz, Mustafa Selman[Abstract not Available]Öğe Fabrication of thermoresponsive PEGMA colloids for controlled drug delivery(AMER CHEMICAL SOC, 2016) Atas, Mehmet Sahin; Ozkaya Balci, A. Nur; 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 Facile synthesis of boronic acid-functionalized nanocarriers for glucose-triggered caffeic acid release(SPRINGER, 2015) Ulasan, Mehmet; Yavuz, Emine; Cengeloglu, Yunus; Yavuz, Mustafa SelmanIn this study, boronic acid-functionalized methacrylate-based nanoparticles were synthesized via surfactant-free emulsion polymerization in one pot. Uniform (polydispersity index < 0.05) sub-100 nm nanoparticles were obtained. The changes of average hydrodynamic diameter and polydispersity index of nanoparticles against boronic acid content in total monomer and acetone percentage in the solvent mixture were investigated. Polymerization kinetics in terms of monomer conversion rate was monitored by gravimetric method. The nanoparticles were characterized by scanning electron microscopy and dynamic light scattering. The boron content in the nanoparticles was confirmed by electron-dispersive X-ray spectroscopy. Further, the nanoparticles were combined with caffeic acid. Caffeic acid carrying nanoparticles were titrated against glucose or fructose in which caffeic acid is released by the displacement reaction in a controlled manner. The displacement of caffeic acid and glucose was monitored by UV-visible spectral change. Furthermore, in vitro biocompatibility of nanoparticles was tested in NIH-3T3 cells, which resulted no significant toxicity effect on the cells.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 Investigation of absorption characteristics of fetal bovine serum (FBS) due to interaction with continuum VIS-NIR laser(AMER CHEMICAL SOC, 2014) Cavusoglu, Halit; Yavuz, Mustafa Selman; Yilmaz, Mehmet Fatih[Abstract not Available]Öğe Light-Driven Unidirectional Liquid Motion on Anisotropic Gold Nanorod Arrays(WILEY-BLACKWELL, 2015) Yilmaz, Mehmet; Kuloglu, Hamit Bugra; Erdogan, Hakan; Cetin, Saime Sebnem; Yavuz, Mustafa Selman; Ince, Gozde Ozaydin; Demirel, Gokhan[Abstract not Available]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]
