Nanobilim ve Teknoloji Araştırma ve Uygulama Merkezi Yayın Koleksiyonu
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Öğe Modification of halloysite clay nanotubes with various alkyl halides, and their characterization, blood compatibility, biocompatibility, and genotoxicity(Elsevier Ltd, 2021) Can, Mehmet; Demirci, Şahin; Yıldırım, Yıldız; Çakır Çoban, Canan; Türk, Mustafa; Şahiner, NurettinHalloysite nanotubes (HNTs) clay were modified with alkyl halides, bromoethane (BrE), bromodecane (BrD), and bromooctadecane (BrOD), respectively. The FT-IR spectra of modified HNTs demonstrated an increase in the intensity of aliphatic –CH2 peaks at 2920 and 2850 cm−1 proportional to the number of C atoms in the modifying agent confirming the success of chemical modification with corresponding alkyl halides. Surface charge of NaOH treated HNTs, −65.7 ± 5.1 mV was increased to −37.1 ± 2.4, −40.6 ± 5.3, and −44.7 ± 1.9 mV, respectively upon chemical modification with BrE, BrD, and BrOD. The Surface area of the HNT clays, 43.2 ± 1.3 m2/g was also increased to 59.8 ± 2.7, 56.9 ± 2.1, and 47.9 ± 1.7 m2/g for BrE, BrD, and BrOD modified HNT clays, respectively. Base-activated HNT clays at 1 mg/mL concentration found to be nonhemolytic with 3.5 ± 1.2% hemolysis ratio, whereas HNT-BrOD clays were slightly exceeded hemolytic safety level with 6.6 ± 0.2% hemolysis induction. Base-activated HNT and HNT-BrOD clays were found to show antithrombogenic character with more than 100% blood clotting indexes,107.6 ± 1.8, and 106.5 ± 1.9%, respectively. Cytotoxicity studies of HNTs on L929 fibroblast cells revealed that HNTs in 12.5–200 μg/mL concentration range were shown dose-dependent cell viability, and above 50% cell viability was maintained at 200 μg/mL in all forms of HNT based clays administered.Öğe Poly(vinyl amine) microparticles derived from N-Vinylformamide and their versatile use(Springer Science and Business Media Deutschland GmbH, 2022) Demirci, Şahin; Sutekin, S. Duygu; Kurt, Saliha B.; Güven, Olgun; Şahiner, NurettinCationic polymers with primary amine groups that can easily be functionalized or coupled with substrates by complexation or hydrogen bonding are especially advantageous in preparing particles for biomedical applications. Poly(vinyl amine) (PVAm) is a cationic polyelectrolyte containing the highest number of primary amine groups among any other polymers. Here, we introduce a general method in synthesizing PVAm microparticles via a surfactant-free water-in-oil emulsion technique using cyclohexane as the oil phase and aqueous PVAm solution as the dispersed phase. PVAm particles were prepared to employ two different bifunctional chemical crosslinkers, divinyl sulfone (DVS) and poly(ethylene glycol) diglycidyl ether (PEGGE). The prepared particles were further treated with HCl to protonate the amine groups of PVAm within particles. The effect of crosslinker types and pH on the hydrolytic degradation of PVAm particles were also investigated at three different solution pHs, 5.4, 7.4, and 9, to simulate the skin, blood, and intestinal pH environments, respectively. The blood compatibility of the PVAm particles was evaluated by in vitro hemolysis and blood clotting assays. Furthermore, antifungal and antibacterial efficacy of PVAm-based particles and their protonated forms were tested against C. albicans yeast and E. coli, S. aureus, B. subtilis, and P. aeruginosa bacterial strains.Öğe Environmental application of PEI based hydrogels in different morphology and sizes: Bulk, microgel, and cryogel(Amer Chemical Soc, 2015) Şahiner, Nurettin; Demirci, Şahin; Şahiner, Mehtap; Al-Lohedan, Hamad; Aktaş, NahitÖğe Monodisperse polymeric ionic liquid microgels by post modifications and their versatile biomedical applications(Amer Chemical Soc, 2015) Şahiner, Nurettin; Yaşar, Alper; Yıldız, Sema; Demirci, Şahin; Aktaş, Nahit[Anstract Not Available]Öğe Phosphazene-based covalent organic polymers as metal-free catalysts with improved H2 generation from NaBH4 in methanol with superior catalytic activity and re-generation ability (vol 12, 112066, 2024)(Elsevier Sci Ltd, 2024) Demirci, Şahin; Yıldız, Mustafa; Şahiner, NurettinÖğe Synthesis and Properties of Inulin Based Microgels(Elsevier Science Bv, 2014) Şahiner, Nurettin; Sağbaş, Selin; Yoshida, Hiroaki; Lyon, L. AndrewCross-linked inulin (X-inulin) microparticles were synthesized in reverse micelles using water-in-oil microemulsion polymerization. Linear inulin was crosslinked with divinyl sulfone (DVS) in a sodium bis(2-ethylhexyl) sulfosuccinate (AOT) inverse microemulsion under basic conditions. These particles were demonstrated to be excellent scaffolds for the in situ synthesis of CdS quantum dots (Q-dots). The inulin-based particles were shown to be non-cytotoxic in fibroblast cell culture, and degradable under acidic and basic conditions. Furthermore, gallic acid and caffeine were used as model drugs for loading and release studies from these particles, illustrating their potential as drug carriers with controlled release. (C) 2014 Published by Elsevier B.V.Öğe Effects of size, structure, charge, and porosity of hydrogel-metal composite catalyst systems on hydrogen generation from the hydrolysis of NaBH4(Amer Chemical Soc, 2013) Şahiner, Nurettin; Seven, Fahriye; Turhan, Tuğce; Karacan, Elif; Cağlar, AyselÖğe Ionic liquid colloids (ILC) based on polymeric microgel: Synthesis and characterizations(Amer Chemical Soc, 2013) Şahiner, Nurettin; Turhan, Tuğce; Lyon, L. AndrewÖğe Macroporous cryogels syntheses and characterizations(Amer Chemical Soc, 2013) Seven, Fahhriye; Karacan, Elif; Turhan, Tuğçe; Şahiner, Nurettin[Anstract Not Available]Öğe Imprinting hydrogels with metal ions for metal nanoparticle preparation and use in hydrogen production as catalysis media(Amer Chemical Soc, 2013) Seven, Fahriye; Yetişkin, Berkant; Turhan, Tuğce; Karacan, Elif; Şahiner, NurettinÖğe Preparation of biopolymeric particles from natural inulin(Amer Chemical Soc, 2013) Sılan, Coşkun; Sağbaş, Selin; Şahiner, Nurettin[Anstract Not Available]Öğe Preparation of p(vinyl phosphonic acid) microgels and its metal nanoparticle containing composites for H2 generation from the hydrolysis of sodium borohydride(Amer Chemical Soc, 2013) Sağbaş, Selin; Şahiner, Nurettin[Anstract Not Available]Öğe In situ synthesis of conductive polymers within covalent organic frameworks(Amer Chemical Soc, 2017) Şahiner, Nurettin; Demirci, ŞahinÖğe In situ preparation of various metal nanoparticles within hydrogel networks and their application in catalysis(Amer Chemical Soc, 2011) Şahiner, Nurettin; Özay, Özgür; Bütün, Sultan; Demir, Veil; Dibek, Burak; Aktaş, Nahit; He, JibaoÖğe Polyethyleneimine based ionic liquid colloids(Amer Chemical Soc, 2014) Şahiner, Nurettin; Demirci, Şahin; Aktaş, Nahit[Anstract Not Available]Öğe Tannic acid based natural particle for versatile use(Amer Chemical Soc, 2014) Şahiner, Nurettin; Sağbaş, Selin; Aktaş, Nahit[Anstract Not Available]Öğe Thiourea-Isocyanate-Based Covalent Organic Frameworks with Tunable Surface Charge and Surface Area for Methylene Blue and Methyl Orange Removal from Aqueous Media(Mdpi, 2022) Sağbaş Suner, Selin; Demirci, Şahin; Sutekin, Duygu S.; Yılmaz, Selehattin; Şahiner, NurettinA thiourea hexamethylene diisocyanate covalent organic framework (TH COF) was synthesized by adjusting the surface charge and surface area. The surface charge value of TH COF, -3.8 +/- 0.5 mV, can be changed to -29.1 +/- 0.4 mV by treatment with NaOH (dp-TH) and 17.1 +/- 1.0 mV by treatment with HCl (p-TH). Additionally, the surface area of TH COF was 39.3 m(2)/g, whereas the surface area of dp-TH COF and p-TH COF structures were measured as 41.4 m(2)/g and 42.5 m(2)/g, respectively. However, the COF structure had a better adsorption capability with acid and base treatments, e.g., dp-TH COF absorbed 5.5 +/- 0.3 mg/g methylene blue (MB) dye, and p-TH COF absorbed 25.9 +/- 1.4 mg/g methyl orange (MO) dye from 100 mL 25 ppm aqueous dye solutions, thereby increasing the MB and MO absorption amounts of the TH COF structure. Furthermore, by calculating the distribution, selectivity, and relative selectivity coefficients, the absorption capacity order was determined as dp-TH > TH > p-TH COFs for the MB dye, whereas it was p-TH > TH > dp-TH COFs for the MO dye. Finally, the reusability of dp-TH COF for MB absorption and p-TH COF for MO absorption were investigated. After five repeated uses, dp-TH COF retained 64.6 +/- 3.7% of its absorption ability, whereas p-TH COF preserved 79.7 +/- 3.2% of its absorption ability relative to the initial absorption amount.Öğe The Removal of Cyanide Ions from Aquatic Environments by Quaternizable p(4-VP) Hydrogels of Different Dimensions(Springer, 2013) Şahiner, Nurettin; Özay, Özgür; Aktaş, NahitHydrogels based on p(4-VP) of different dimensions were prepared and, after chemical modification, were used in the removal of one of the most potent toxic materials, cyanide. Macro and micron p(4-VP) hydrogel swelling behavior was evaluated in various aquatic environments. HCl, bromoethane, 1-bromobutane, 1-bromohexane, and 2-bromoethylamine were used as quaternizing agents to generate positive charges on both p(4-VP) macrogels and microgels. The modified p(4-VP) macrogels and microgels were used in cyanide ion removal for the first time from aqueous environments. The p(4-VP)-HCl at macro and micro sizes removed almost 49 and 61 mg cyanide ions per gram hydrogel in deionized water after modification, respectively. Moreover, the absorption capacity of the modified p(4-VP) hydrogel did not change significantly in tap, drinking, and creek waters. Parameters that affect the absorption process, such as cyanide concentration, contact time, hydrogel amount, and contaminated water source, were investigated. Additionally, magnetic field responsive macro and micro p(4-VP) hydrogel composites provided many advantages, such as easy handling after cyanide absorption, e. g., ready removal of cyanide-loaded p(4-VP) composites with an externally applied magnetic field. Langmuir and Freundlich adsorption isotherms were applied to the data obtained for cyanide uptake from aqueous environments.Öğe pH-Responsive Amphoteric p (APTMACl-co-AMPS) Hydrogel as Effective Multiple Dye Sponge Network From Aqueous Media(Frontiers Media Sa, 2022) Demirci, Şahin; Ari, Betül; Aktaş, Nahit; Şahiner, NurettinHere, the cationic poly (3-acrylamidepropyl trimethyl ammonium chloride) [p (APTMACl)], anionic poly (2-acrylamido-2methylpropane sulfonic acid) [p (AMPS)], and amphoteric poly (APTMACl-co-AMPS) hydrogels were prepared via free-radical polymerization techniques as pH-sensitive hydrogels. The prepared systems were used in methylene blue (MB), and Eosin Y (EY) removal from aqueous media. HCl-treated p (APTMACl-co-AMPS) hydrogels prepared in 1:3 mol ratio adsorbed higher amount of MB and EY from their corresponding 50 ml 50 ppm aqueous solutions that are 47.5 +/- 0.9, and 10.7 +/- 0.1 mg/g, respectively. Also, the adsorbed amount of MB and EY by HCl-treated p (APTMACl-co-AMPS) hydrogels decreased with the increase in the medium pH from 3.0 to 9.0. It was also observed that HCl-treated p (APTMACl-co-AMPS)-3 hydrogels removed 39.2 +/- 0.2, and 28.1 +/- 1.0 mg/g MB and EY dyes simultaneously from their corresponding 50 ml 50 ppm aqueous mixture solutions. MB and EY adsorption by HCl-treated p (APTMACl-co-AMPS)-3 hydrogels were found to abide by pseudo-first-order adsorption kinetics. Moreover, MB adsorption by HCl-treated p (APTMACl-co-AMPS) hydrogels were found to fit with Freundlich, EY adsorption fit with Langmuir isotherms. The distribution coefficient values of HCl-treated p (APTMACl-co-AMPS) hydrogels were calculated as 3.7 +/- 0.1 and 1.3 +/- 0.1 for MB and EY, respectively. The calculated selectivity coefficient value showed that HCl-treated p (APTMACl-co-AMPS) hydrogels are at least 3-fold higher selective to MB than EY.Öğe Porous and modified HA particles as potential drug delivery systems(Elsevier Science Bv, 2012) Şahiner, Nurettin; Sılan, Coşkun; Sağbaş, Selin; Ilgın, Pınar; Bütün, Sultan; Erduğan, Hüseyin; Ayyala, Ramesh S.Composite silica-hyaluronic acid (Si-HA) micro particles were synthesized, employing tetraethyl orthosilicate (TEOS) in the presence of linear HA and a crosslinker, divinyl sulfone (DVS) via a water-in-oil microemulsion polymerization technique. Porous HA (PHA) hydrogel particles were generated after removal of silica particles upon treatment of HA composites with hydrofluoric acid (FIF). Furthermore, HA particles were quaternized (QHA) by chemical modification using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride as a quarternization agent. The size of HA based particles were ranged between 1.26 and 2.95 mu m. The PHA particles have a surface area of 2.7 m(2)/g confirmed by the surface area measurements. Modified HA particles were used in the absorption and release studies of two model drugs in PBS, trimethoprim (TMP) and sodium diclofenac (SDF) which are acidic and basic in nature, respectively. The ability to control the size, charge and porosity of the HA particles which showed almost linear drug release profiles. (C) 2012 Elsevier Inc. All rights reserved.
