Chemistry / Kimya
Permanent URI for this collectionhttps://hdl.handle.net/11147/4072
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Article Citation - WoS: 6Citation - Scopus: 7Utilization of Electrospun Polystyrene Membranes as a Preliminary Step for Rapid Diagnosis(John Wiley and Sons Inc., 2016) Işık, Tuğba; Horzum, Nesrin; Yıldız, Ümit Hakan; Liedberg, Bo; Isık, Tuğba; Demir, Mustafa Muammer; 04.01. Department of Chemistry; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyRecent advances in clinical practice drive deoxyribonucleic acid (DNA) as an important class of biomarker. Monitoring the change in their concentration suggests the initiation and/or progression of various disorders. However, low quantity of DNA biomarkers in body fluids requires a delicate isolation methodology that provides efficient separation and easy handling. This study describes a newer-generation separation technology relying on electrospun fibers of sub-micrometer diameter of a commodity polymer for DNA biomarkers in simulative serum. Fibrous polystyrene membranes are prepared by electrospinning and they are subjected to post-modification with Au. The composite membranes may provide a convenient environment for the removal of bovine serum albumin (BSA) from BSA and DNA mixtures. The eluent can be used as an efficient tool for detection of DNA biomarkers associated with diagnosis of numerous life-threatening diseases.Article Citation - WoS: 20Citation - Scopus: 23Rhodamine-Immobilised Electrospun Chitosan Nanofibrous Material as a Fluorescence Turn-On Hg2+ Sensor(John Wiley and Sons Inc., 2016) Horzum, Nesrin; Mete, Derya; Emrullahoğlu, Mustafa; Üçüncü, Muhammed; Emrullahoğlu, Mustafa; Mete, Derya; Demir, Mustafa Muammer; 01. Izmir Institute of Technology; 04.04. Department of Photonics; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of ScienceA turn-on fluorescence sensing system for mercuric (Hg2+) ions relying on a modified rhodamine B–chitosan fluorophore moiety was developed. This novel sensing approach relies on the simultaneous electrospinning of chitosan and rhodamine B hydrazide with phenylisothiocyanate functionality in hexafluoroisopropanol solution at 3.4 kV cm−1. The electrospun mats exhibited not only considerably enhanced fluorescence intensity in the presence of mercury ions, a result attributed to the ring opening of the spirolactam unit of the rhodamine-based fluorophore, but also a remarkably high sensitivity and selectivity toward Hg2+. In effect, the strategy has the potential to open new avenues in the design and development of other high-performance nanofibrous sensing materials for detecting target metal species of environmental interest.Article Citation - WoS: 6Citation - Scopus: 6Hierarchial Coassembly of a Cyanine Dye in Poly(vinyl Alcohol) Fibrous Films by Electrospinning(American Chemical Society, 2013) Demir, Mustafa Muammer; Horzum, Nesrin; Özçelik, Serdar; Özçelik, Serdar; Demir, Mustafa Muammer; 04.01. Department of Chemistry; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologyWe report molecular aggregate formation of TTBC (1,1′,3,3′- tetraethyl-5,5′,6,6′-tetrachlorobenzimidazolocarbocyanine) in submicrometer-sized PVA (poly(vinyl alcohol)) fibers by electrospinning. The formation of the molecular aggregate is examined by solution and instrumental parameters of electrospinning. The precursor solution of PVA/TTBC, in the range of 0.016-0.065 wt % is subjected to electrospinning under an electrical field ranging from 0.95 to 1.81 kV cm-1. Both randomly deposited and uniaxially aligned fibers are achieved by using two parallel-positioned metal strips as counter electrode. Photoluminescence and polarized Fourier transform infrared spectroscopies are employed to determine spectral properties of the fibers. H-aggregates are formed within the electrospun fibers, regardless of their alignment, and H- and J-type aggregates coexist in the alternative spin-coated and the cast films. A strongly polarized photoluminescence emission is observed in the direction of uniaxially aligned fibers as a result of the orientation of the H-aggregates along the fiber axis. We demonstrate that electrospinning is a process capable of forming and orienting TTBC aggregates during the structural development of the polymer/dye nanofibers. These fibrous films may potentially find applications in optics and electronics.Article Citation - WoS: 16Citation - Scopus: 17Electrospun Amino-Functionalized Pdms as a Novel Spme Sorbent for the Speciation of Inorganic and Organometallic Arsenic Species†(Royal Society of Chemistry, 2013) Boyacı, Ezel; Horzum, Nesrin; Çağır, Ali; Demir, Mustafa Muammer; Eroğlu, Ahmet Emin; Demir, Mustafa Muammer; Eroğlu, Ahmet Emin; 04.01. Department of Chemistry; 03.09. Department of Materials Science and Engineering; 03. Faculty of Engineering; 04. Faculty of Science; 01. Izmir Institute of TechnologySol–gel based amine-functionalized SPME fibers (PDMS-weak anion exchanger) were prepared and used for direct mode extraction of dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), and arsenate (As(V)) from aqueous solutions followed by HPLC-ICPMS determination. Two different methods of coating were employed: (i) electrospinning and (ii) dip coating. Electrospinning was used for the first time for preparation of sol–gel based SPME fibers and was found to be superior in terms of extracted amount of arsenicals, coating homogeneity, accessibility of amine groups on the surface, and preparation time for a single fiber. Various parameters such as solution pH, extraction time, agitation speed, extraction temperature, and ionic strength were studied. Optimum extraction conditions were determined as pH of 5.0, extraction time of 30 min, agitation speed of 700 rpm, and extraction temperature of 20 C. Extraction ability of the novel coating decreased by the addition of NaCl as a consequence of the competition between anionic arsenic species and chloride ions for active sites of the weak anion exchanger. This novel sol–gel coating prepared by electrospinning was found to be promising for SPME applications. Vibrational spectroscopy revealed the alignment of PDMS chains by elongational force under electrospinning process. The chain alignment accordingly orients the pendant amino functional groups perpendicular to the fiber surface, which may develop the free active functional groups available to the medium and lead to the enhancement of the extraction performance. Moreover, the proposed coating strategy through electrospinning might be able to break new ground for various applications in analytical chemistry as well as other disciplines.