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4-Vinylpyridine-Based Smart Nanoparticles with N-Isopropylacrylamide, 2-Hydroxyethyl Methacrylate, Acrylic acid, and Methacrylic Acid for Potential Biomedical Applications
(Bentham Science Publ Ltd, 2011) Şahiner, Nurettin; Özay, Özgür; Aktaş, Nahit
Stimuli-responsive (pH, temperature and magnetic field) 4-vinylpyridine (4-VP)-based nanoparticles in copolymeric formulation with core-shell morphology were synthesized using N-isopropylacrylamide (NIPAM), 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AAc), and methacrylic acid (MAc) as shell-forming monomers. Keeping the 4-VP ratio constant and varying the comonomer amounts produced particles with variant shell thickness. Multi-responsive p(4-VP)-based nanoparticles were further modified by reacting with different functional groups containing bromoalkanes by quaternization. These p(4-VP)-based particles were also utilized to include composite materials by encapsulating separately prepared magnetic ferrites. To demonstrate the potential usage of the synthesized particles and their modified forms as drug delivery devices, naproxene sodium salt as an antibacterial drug was used for in vitro release studies in PBS.
A neutral state colorless phosphazene/carbazole hybride dendron and its electrochromic device application
(Elsevier Science Sa, 2015) Sezgin, Meryem; Özay, Özgür; Koyuncu, Sermet; Ozay, Hava; Koyuncu, Fatma Baycan
In this work, a new phosphazene/carbazole hybride dendron (PC) was synthesized and then directly coated onto ITO glass surface to provide a dendritic polymer network, poly-(PC), by using potentiodynamic electrochemical process. Structure of dendron was identified by FT-IR, H-1 and P-31 NMR, and also TOF-MS analyses. The optical and electrochemical properties of PC and its electrochemical crosslinked product were investigated by using UV-vis absorption, fluorescence and CV techniques. A neutral, colorless electrochromic device was constructed in the sandwich configuration [indium tin oxide (ITO)coated glass/anodically coloring material (poly-(PC))//gel electrolyte//cathodically coloring material (PEDOT)/ITO-coated glass] and revealed a short response time (about 0.5 s), high coloration efficiency (981 cm(2) C-1) and high redox stability. (C) 2015 Elsevier B.V. All rights reserved.
A New Approach to Synthesis of Highly Dispersed Gold Nanoparticles via Glucose Oxidase-Immobilized Hydrogel and Usage in The Reduction of 4-Nitrophenol
(Wiley-V C H Verlag Gmbh, 2020) Ozay, Hava; Tarimeri, Nur; Gungor, Zeynep; Demirbakan, Burcak; Ozcan, Burcu; Sezgintürk, Mustafa Kemal; Özay, Özgür
In this study, for the first time in the literature, synthesis of Au(0) nanoparticles supported by a crosslinked gel structure was performed via enzyme-mediated reduction of Au(III) ions without using any chemical reductant. In our newly-developed method, glucose oxidase enzymes immobilized in the crosslinked gelatine structure ensured simultaneous reduction of the Au(III) ions diffused within the gel to Au(0). The Au@Gel obtained was structurally characterised with TEM (Transmission electron microscopy), EDX (Energy dispersive X-ray analysis) elemental mapping, XPS (X-Ray photoelectron spectroscopy) and XRD (X-Ray Diffraction) analyses. The catalytic activity of Au(0) particles with nearly 8 nm size in the Au@Gel was investigated for the reduction of 4-nitrophenol (4-NP) as a model compound in the presence of NaBH(4)as reducing agent. The activation parameters for the reduction reaction of 4-nitrophenol in the presence of Au@Gel catalyst were determined as E-a= 30.16 kJmol(-), Delta H= 27.52 kJmol(-)and Delta S= -197.45 Jmol(-)K(-). The Au@Gel catalyst system, with good catalytic activity, simultaneously has nearly perfect reusability.
A new candidate for wound dressing materials: s-IPN hydrogel-based highly elastic and pH-sensitive drug delivery system containing pectin and vinyl phosphonic acid
(Pergamon-Elsevier Science Ltd, 2024) Şeref, Elif; Ilgın, Pınar; Özay, Özgür; Özay, Hava
In this study, we developed pH-sensitive semi-interpenetrating network (s-IPN) hydrogels, composed of pectin, 2hydroxyethyl methacrylate (HEMA), and vinyl phosphonic acid (VPA) using N,N'-methylene bis(acrylamide) (MBA) as a cross-linker with the free-radical polymerization method. The formation of s-IPNs was confirmed by FTIR studies. SEM images showed the addition of VPA to the polymeric matrix of s-IPN hydrogels formed additional microporous structures within the hydrogel network. The s-IPN hydrogel had perfect mechanical features like stretchability, compressibility and elasticity. Additionally, the swelling behavior of s-IPN hydrogels in deionized water and solutions with diverse pH was assessed. To research use as a controlled drug delivery material, the hydrogel was loaded with cimetidine and trimethoprim. At pH 7.2, the in vitro drug release profile was observed and nearly 60 % of the drugs were released from s-IPN hydrogel within 10 h. Additionally, the most appropriate kinetic release model was Higuchi, followed by Korsmeyer-Peppas. Finally, silver sulfadiazine (SSD) was added to s-IPN hydrogel for use as a smart wound dressing material. Antimicrobial analysis of the SSDloaded s-IPN hydrogel found it had antimicrobial features, inducing 15, 17 and 23 mm inhibition zones against Staphylococcus aureus (gram-positive), Escherichia coli (gram -negative) and Candida albicans (fungus) microorganisms, respectively. In light of the obtained results, based on being easily shapable with appropriate mechanical and physical features, pectin/p(HEMA-co-VPA) and pectin/p(HEMA-co-VPA)@SSD s-IPN hydrogels are potential candidates for use as controlled drug delivery and wound dressing materials in the biomedical field.
A new dual stimuli responsive hydrogel: Modeling approaches for the prediction of drug loading and release profile
(Pergamon-Elsevier Science Ltd, 2019) Ilgin, Pinar; Ozay, Hava; Özay, Özgür
In this study, N-tert-butylmaleimic acid was designed for the first time and synthesized by reaction of maleic anhydride with tert-butylamine and evaluated as a new functional monomer for preparation of new pH-responsive hydrogels. Its structure was verified with FTIR, H-1 and C-13 NMR. A new pH- and temperature-responsive hydrogel p(TBMAC-co-NIPAM), based on TBMAC and NIPAM, was successfully prepared via free-radical copolymerization technique in an aqueous solution. The chemical and structural properties of the hydrogels were identified by FTIR and SEM. The swelling properties of these hydrogels were systematically investigated according to various parameters such as time, temperature, pH and salt effects, and the results show that they are strongly influenced by the content of TBMAC and exhibit strong pH, temperature and salinity sensitivity. In addition, swelling kinetics and water diffusion mechanisms in hydrogels were discussed. In addition, in vitro drug release studies were performed in simulated gastric, isotonic serum and intestinal fluid at two different temperatures (23 and 37 degrees C) by taking R6G as a model drug. Drug loading results were investigated with various isotherm models such as Langmuir, Freundlich, Temkin and Dubinin-Radushkevich. Various kinetic models such as zero-order, first-order, Higuchi model and Korsmeyer-Peppas models were applied to determine the drug release mechanism. The results indicated that drug release involves non-Fickian transport mechanism. These results suggest that this new pH - and thermo-responsive hydrogel may be used to improve sustained release of drugs.
A novel hydrogel containing thioether group as selective support material for preparation of gold nanoparticles: Synthesis and catalytic applications
(Elsevier Science Bv, 2019) Ilgin, Pinar; Özay, Özgür; Ozay, Hava
In this study, firstly N-metacrylamido thiomorpholine containing thioether group was synthesized as monomer. Then, p(AAm-co-MTM) hydrogels were prepared from the redox polymerization of acrylamide and N-metacrylamido thiomorpholine as a selective support material. p(AAm-co-MTM) hydrogel-gold nanoparticles were obtained as a result of the reduction of the selectively absorbed gold(III) ions by the hydrogel network using NaBH 4 as reducing agent. All materials were characterized using techniques such as SEM, EDX, TEM and XRD analysis. It was determined that p(AAm-co-MTM)-Au composite material has high catalytic activity for the reduction of 4-nitrophenol. The activation parameters of the reduction reaction of 4-nitrophenol using NaBH4 in the presence of p(AAm-co-MTM)-Au catalyst were calculated as E-a = 38.80 kJ/mol, Delta H-# = 36.16 kJ/mol and Delta S-# = - 161.37 J/mol K.
A single-use electrochemical biosensor system for ultrasensitive detection of Aflatoxin B1 in rice, corn, milk, peanut, chili pepper samples
(Academic Press Inc Elsevier Science, 2024) Demirbakan, Burçak; Tarımeri Köseer, Nur; Uzman, Ecem; Özay, Özgür; Özay, Hava; Sezgintürk, Mustafa Kemal
Aflatoxin B1, a common food contaminant in peanuts and corn and a genotoxic carcinogen in humans poses a significant risk for hepatocellular carcinoma, making its detection crucial; this study aims to develop a label-free electrochemical biosensor using a disposable indium tin oxide polyethylene terephthalate (ITO-PET) electrode modified with 3-Aminopropyltriethoxysilane for detecting Aflatoxin B1 in real food samples. Initially, optimization steps for the proposed biosensor were conducted using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. Characterization steps such as storage capacity, regeneration, and single frequency impedance (SFI) were completed for the proposed disposable biosensor after the optimization steps. The electrochemical biosensor, based on AFB1, exhibited excellent repeatability and reproducibility. It had a broad dynamic detection range from 0.1 fg/mL to 500 fg/mL, with low limits of detection (LOD) and quantitation (LOQ) at 0.19 fg/mL and 0.65 fg/mL, respectively. Finally, the proposed AFB1-based biosensor system was applied to real food samples (rice, chili pepper, milk, corn, and peanuts) for testing and validation.
A soft hydrogel reactor for cobalt nanoparticle preparation and use in the reduction of nitrophenols
(Elsevier Science Bv, 2010) Şahiner, Nurettin; Özay, Hava; Özay, Özgür; Aktaş, Nahit
Bulk poly(2-acrylamido-2-methyl-1-propansulfonic acid) (p(AMPS)) hydrogels were prepared by irradiation of an aqueous solution of AMPS in the presence of crosslinker and photoinitiator. These p(AMPS) hydrogel networks were utilized for in situ cobalt nanoparticle synthesis by reduction of metal ions absorbed into the hydrogel network with a reducing agent, i.e., NaBH(4). TEM images confirmed that Co particles are about 100 nm in size. The hydrogel network with embedded Co nanoparticles was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP) and 2-nitrophenol (2-NP) in aqueous media in the presence of an excess amount of NaBH4. The kinetics of the reduction reaction under different reaction conditions was investigated to determine the activation parameters. Activation energies are 27.8 kJ mol(-1) and 39.3 kJ mol(-1) for 4-NP and 2-NP, respectively. It was found that hydrogel-Co composites were 99% active after 5 days storage. (C) 2010 Elsevier B.V. All rights reserved.
Adsorption of Malachite Green from Aqueous Solution Using Hydroxyethyl Starch Hydrogel Improved by Graphene Oxide
(Springer, 2022) Onder, Alper; Kivanc, Mehmet Riza; Durmus, Secil; Ilgin, Pinar; Ozay, Hava; Özay, Özgür
This study is the first report of the preparation of hydroxyethyl starch (HES) hydrogels rapidly crosslinked with divinyl sulfone in a single step and single pot. To develop the physical and chemical features of hydrogels, Graphene oxide (GO) nanoparticles were combined with the crosslinked HES. In addition to swelling studies, structural characterization of the samples was conducted with a scanning electron microscope (SEM) and transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), Brunauer-Emmett-Teller (BET) analysis and thermogravimetric analysis (TGA). For the removal of malachite green model dye by GO-HES, the effects of GO content, solution concentration, temperature, contact duration, dosage and pH on varying adsorption features were researched. Additionally, adsorption isotherms, kinetic and thermodynamic systematics were analyzed. The maximum adsorption capacity of GO-HES composite hydrogel was found to be 89.3 mg/g for Langmuir isotherm. The possible adsorption mechanism of the composite hydrogels for malachite green dye involved electrostatic, hydrogen bonding, and pi-pi interactions. In addition to reasonable cost and simple synthesis method, the prepared composite materials have potential use in wastewater treatment as adsorbents for the removal of dye from aqueous solutions due to efficient adsorption capacity.
Adsorption of methylene blue from aqueous solution using poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-2-hydroxyethyl methacrylate) hydrogel crosslinked by activated carbon
(Taylor and Francis Ltd., 2023) Ilgın, Pınar; Önder, Alper; Kıvanç, Mehmet Rıza; Özay, Hava; Özay, Özgür
This study aimed to develop an environmentally friendly, inexpensive, and efficient adsorbent for removing methylene blue (MB) dye from wastewater using a three-dimensional porous poly(2-Acrylamido-2-methyl-1-propanesulfonic acid-co-2-Hydroxyethyl Methacrylate), p(AMPS-co-HEMA) composite hydrogel crosslinked with vinyl-functionalized activated carbon (VAC). The surface morphology and chemical structure of the crosslinker were characterized using transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray spectroscopy (XRD) and Fourier transform-infrared spectroscopy (FT-IR) instruments. The surface morphology, chemical structure and thermal properties of the hydrogel were also characterized using scanning electron microscopy (SEM), FT-IR and thermogravimetric analyzers (TGA). Experimental parameters affecting the adsorption behavior, such as initial dye concentration, time, dosage, pH, and temperature, were systematically investigated. Hydrogel achieved optimal MB removal efficiency (69.53%) at an initial MB concentration of 250 mg/L (1 mg/mL, pH not adjusted) over 24 h. Adsorption kinetics, isotherm, thermodynamic studies, and reusability were investigated. Experimental adsorption isotherm and kinetic data followed the Langmuir model and pseudo-second-order kinetics with a maximum adsorption capacity of 284.90 mg/g hydrogel at 293 K. Thermodynamic findings proved the spontaneity and endothermic behavior of the adsorption process. After 5 adsorption-desorption cycles, the adsorption capacity of the composite hydrogel decreased by only 7.51 mg/g compared to the initial adsorption capacity.
An innovative approach to use zeolite as crosslinker for synthesis of p(HEMA-co-NIPAM) hydrogel
(Springer Wien, 2022) Durmus, Secil; Yilmaz, Betul; Onder, Alper; Ilgin, Pinar; Ozay, Hava; Özay, Özgür
This study introduced a modified method to synthesize organic-inorganic hybrid crosslinker based on zeolite. First, zeolite nanoparticles were modified with 3-(aminopropyl)trimethoxysilane. Then, the amine-functionalized zeolite has been reacted with the glycidyl methacrylate via an epoxide ring-opening mechanism. The vinyl-functionalized zeolite was applied as a crosslinking agent to form hydrogel network. A novel temperature-sensitive nanocomposite hydrogel was prepared by crosslinking N-isopropylacrylamide as a comonomer and 2-hydroxyethyl methacrylate as a monomer with free-radical polymerization. Results showed that p(2-hydroxyethyl methacrylate-co-N-isopropylacrylamide)/vinyl-functionalized zeolite nanocomposite hydrogel has a chemically crosslinked and porous network structure. The content of crosslinker and monomers had obvious effects on the swelling ratio of the nanocomposite hydrogel. The temperature and salt-sensitive behavior of the hydrogels are also discussed. We offer a multifunctional crosslinker for preparing sensitive materials that can serve biomedical or environmental applications.
An unusual impedimetric biosensor design based on 3-MPDS for highly sensitive detection of AFB1 in food samples
(Elsevier, 2024) Demirbakan, Burçak; Tarımeri Köseer, Nur; Özay, Özgür; Özay, Hava; Sezgintürk, Mustafa Kemal
Aflatoxin B1 (AFB1), a mycotoxin produced by fungi of the genus Aspergillus, particularly Aspergillus flavus, is recognized as the aflatoxin with the highest carcinogenic and mutagenic potential. This study presents a costeffective, disposable AFB1 biosensor system based on 3-mercaptopropyltrimethoxysilane (3-MPDS) and the highly sensitive impedance technique. The surfaces of the ITO-PET (indium tin oxide/polyethylene terephthalate) electrodes were modified with 3-MPDS, and N-hydroxysuccinimide (NHS) was used as a crosslinker. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques were employed for immobilization, optimization, and analytical studies. Additionally, the surface morphology of the biosensor was analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The biosensor demonstrated a linear range from 0.01 fg/mL to 200 fg/mL, with a limit of detection (LOD) of 0.01 fg/mL and a limit of quantification (LOQ) of 0.04 fg/mL. Finally, the proposed biosensor was tested and validated with real food samples, including rice, peanuts, milk, chili pepper, and corn.
Aromatic organic contaminant removal from an aqueous environment by p(4-VP)-based materials
(Pergamon-Elsevier Science Ltd, 2011) Şahiner, Nurettin; Özay, Özgür; Aktaş, Nahit
p(4-vinylpyridine) (p(4-VP)) hydrogels were prepared in bulk (macro, 5 x 6 mm) and in nanosizes (370 nm) dimensions. The prepared hydrogels were used to remove organic aromatic contaminates such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), phenol (Ph) and nitrobenzene (NB) from an aqueous environment. Important parameters affecting the absorption phenomena, such as the initial concentration of the organic species and the absorbent, absorption rate, absorption capacity, pH and the temperature of the medium, were evaluated for both hydrogel sizes. The absorption capacity of bulk and microgels were found to be 4-NP > 2-NP > Ph > NB. Furthermore, p(4-VP) microgels were embedded in poly(acrylamide) (p(AAm)) bulk hydrogel as a microgel-hydrogel interpenetrating polymer network and proved to be very practical in overcoming the difficulty of using the microgels in real applications. Moreover, it was demonstrated that separately prepared magnetic ferrite particles inserted inside p(4-VP) microgels during synthesis allowed for trouble-free removal of p(4-VP)-magnetic composite microgels from the aqueous environment by an externally applied magnetic field upon completion of their task. (C) 2011 Elsevier Ltd. All rights reserved.
Arsenic (V) removal with modifiable bulk and nano p(4-vinylpyridine)-based hydrogels: The effect of hydrogel sizes and quarternization agents
(Elsevier, 2011) Şahiner, Nurettin; Özay, Özgür; Aktaş, Nahit; Blake, Diane A.; John, Vijay T.
Macrogels and nanogels (5 x 6 mm and 370 nm dimensions, respectively) based on 4-vinylpyridine (p-(4VP)) were prepared using redox and microemulsion techniques. The p(4-VP)-based materials were quaternized with HCl/alkyhalides having different chain lengths to tune the charges (macro and nanogels) and size of nanogels. By developing positive charge on the p(4-VP) materials, they behaved as ion exchangers and used in removal of As(V) from aqueous environments. The prepared p(4-VP) materials were also rendered responsive to magnetic field by in situ incorporation of magnetic metal nanoparticles inside macro p(4-VP) hydrogels and by encapsulation of separately prepared magnetic ferrites by nanosized p(4-VP) particles. Nanoparticles quaternized with HCl (p(4-VP)-HCl) (1 g) removed over 95% of As(V) from a stock solution (10 mg L-1 1000 mL) in 15 min whereas bulk hydrogels removed >82% of the As(V) from an equivalent solution in similar to 12 h. Parameters effecting the As(V) removal, including pH, temperature and ionic strength, were also investigated. The synthesized magnetic p(4-VP) composites could be reused after elution with NaOH and regeneration with quaternization agents; these procedures were facilitated using an externally applied magnetic field. The Langmuir and Freundlich adsorption isotherms were also applied to study the removal of As(V) from aqueous environments. (C) 2011 Elsevier B.V. All rights reserved.
Assessment of release and anticancer effect of innovative pH-responsive and antioxidant-biodegradable hydrogel by using Parthenocissus quinquefolia L. extract as a crosslinker
(Elsevier, 2023) Cömert Önder, Ferah; Kalın, Sevil; Önder, Alper; Özay, Hava; Özay, Özgür
The level of toxicity in cancer treatment with chemotherapy can negatively affect the treatment process. Therefore, targeted drug delivery systems play an important role in reducing treatment-related toxicities. Hydrogels with three-dimensional networks are being investigated as drug delivery systems due to their unique properties such as swelling capacity, biocompatibility, and bioavailability. Poly(2-hydroxyethyl methacrylate-co- methacrylic acid)/PQ (p(HEMA-co-MAA)/PQ) hydrogel was prepared by redox polymerization method using Parthenocissus quinquefolia L. (PQ) plant extract, known for its anticancer, antioxidant, and antimicrobial properties, as a crosslinker. PQ hydrogels were prepared with various monomer and cross-linker ratios. The p(HEMAco-MAA)/PQ10 (1:1) with a highly porous structure exhibited high swelling behavior. The phenolic content of p (HEMA-co-MAA)/PQ10 (1:1) hydrogel which has been determined to have high in vitro biodegradability at pH 6.5, increased with the amount of PQ extract used as crosslinker. The pH-responsive, antioxidant, biodegradable, and highly porous p(HEMA-co-MAA)/PQ10 (1:1) hydrogel showed higher doxorubicin (Dox) release behavior at pH 6.5. The Dox-loaded p(HEMA-co-MAA)/PQ10 (1:1) hydrogel drug carrier showed its anticancer effect on inhibition of colonies and cell proliferation against breast cancer cell lines. Our findings show that the p(HEMAco-MAA)/PQ10 (1:1) hydrogel using the PQ plant extract as a crosslinker will be significant potential in combination and cancer therapy studies.
Ayarlanabilir ve Çoklu Renk Emisyonu Verebilen Kinolin Polimerlerin Sentezleri Ve Karakterizasyonlari
(2015) Bilici, Ali; Doğan, Fatih; Özay, Özgür
Yapılan çalışmada, amino kinolin monomerlerinin farklı oksidantlar vasitasıyla oksidatif polimerizasyonları gerçekleştirildi. Polimerizasyonlar için reaksiyon şartları incelendi. Sentezlenen kinolin polimerlerinin karakterizasyonu UV-Vis, FT-IR, NMR, GPC, SEM, XRD, XPS, CV, floresans, AFM, SEM, TEM ve iletkenlik analizleri ile belirlendi. Farklı dalga boylarında uyarılan polimer çözeltilerinin emisyon karakterleri incelendi. 6AQP-Cu’ın farklı çözücülerde farklı renk emisyonları verdiği, 5AQP’nin ise farklı dalga boylarıda uyarıldığında çoklu renk emisyonu verdiği belirlendi. Elde edilen ürünlerin ısısal stabiliteleri TG/DTG-DTA ve DSC ölçümleri ile tayin edildi. Çalışmanın son aşamasında sentezlenen ürünlerin ısısal katı hal bozunma kinetikleri farklı sınıflara ait bir çok yöntem kullanılarak hesaplandı. Sentezlenen maddelerin bozunma basamaklarına ait matematiksel fonksiyonlar belirlendi. Polimerizasyon ürünlerinin diffüzyon tipi (Dn) mekanizma ile bozunduğu belirlendi.
COLL 490-Colloidal p(4-VP) particles and composites for biomedical application
(Amer Chemical Soc, 2009) Özay, Özgür; Aktaş, Nahit; Dülger, Başaran; Sılan, Coşkun; John, Vijay T.; Şahiner, Nurettin
[Anstract Not Available]
Controllable hydrogen generation by use smart hydrogel reactor containing Ru nano catalyst and magnetic iron nanoparticles
(Elsevier, 2011) Şahiner, Nurettin; Özay, Özgür; İnger, Erk; Aktaş, Nahit
In this study, p(AMPS) hydrogels are synthesized from 2-acrylamido-2-methyl-1-propansulfonic acid (AMPS) via a photo polymerization technique. The hydrogels are used as template for metal nanoparticles and magnetic ferrite nanoparticles. and also as a catalysis vessel in the generation of hydrogen from the hydrolysis of NaBH4. Approximately 5 nm Ru (0) and 20-30 nm magnetic ferrite particles are generated in situ inside this p(AMPS) hydrogel network and then used as a catalysis medium in hydrogen production by hydrolysis of sodium boron hydride in a basic medium. With an applied external magnetic field, the hydrogel reactor, containing Ru and ferrite magnetic particles, can be removed from the catalysis medium; providing on-demand generation of hydrogen. The effect of various parameters such as the initial concentration of NaBH4. the amount of catalyst and temperature on the hydrolysis reaction is evaluated. The activation energy for hydrogen production by Ru (0) nanoparticles is found to be 27.5 kJ mol(-1); while the activation enthalpy is 30.4 kJ mol(-1). The hydrogen generation rate in presence of 5 wt% NaOH and 50 mg p(AMPS)-Ru catalyst is 8.2 L H-2 min(-1) g Ru. (C) 2011 Elsevier B.V. All rights reserved.
Değişik boyutta ve yapıda 4-vinilpiridin (4-VP) esaslı polimerik materyaller ve bunların uygulama alanlarının araştırılması
(Çanakkale Onsekiz Mart Üniversitesi, 2012) Özay, Özgür; Şahiner, Nurettin
Bu çalışmada pH, sıcaklık ve manyetik alana duyarlı p(4-VP) esaslı makro ve mikrojeller NIPAM, AMPSNa, APTMACl, HEMA, AAc, MAAc ve VI monomerleri kullanılarak değişik boyut ve yapılarda sentezlenmiştir. Sentez aşamasından sonra p(4-VP) esaslı makro ve mikrojeller kuarternize edilmiştir. Modifiye edilen kuarternize makro ve mikrojellerin şişme karakterizasyonları yapılmıştır. Ayrıca SEM, TEM, DLS ve TG analizleri ile karakterize edilen değişik boyut ve yapılı hidrojeller üç farklı alanda (1) biyomedikal, (2) kataliz ve (3) çevre uygulamalarında kullanılmıştır.Kuarternize edilmiş p(4-VP) mikrojelleri ve içerisinde Ag ve Cu nanopartikülleri hazırlanan p(4-VP) mikrojellerinin gram pozitif ve gram negatif bakteriler için antimikrobiyal ajan olarak kullanılabilirliği araştırılmıştır. Pozitif yüklü ve manyetik alan duyarlı hazırlanan p(4-VP), p(4-VP-ko-NIPAM) ve p(4-VP-ko-VI) mikrojelleri ise Naproksen Sodyum ilacının PBS'de salım çalışmalarında kullanılmıştır. Katalizör amaçlı çalışmalarda, makro ve mikrojellerin Cu içeren kompozitlerinin 4-nitrofenolün indirgenme ve metilen mavisinin bozunması reaksiyonlarında kullanımı araştırılmıştır. Ayrıca p(4-vinilpiridinyum klorokromat) olarak hazırlanan makrojellerin ise benzil alkolün yükseltgenmesi reaksiyonundaki kullanımı araştırılmıştır. Çevre uygulamalarında ise p(4-V-ko-HEMA) makrojelleri, p(4-VP) makro ve mikrojelleri, kuarternize p(4-VP) makro ve mikrojelleri sırasıyla sulu ortamdan uranyum ve toryum iyonlarının, aromatik organik bileşiklerin ve arsenik iyonlarının absorbsiyonunda kullanılmıştır.
Drug release properties of amphoteric HES/p(AETAC-co-IA) hydrogels decorated with gold nanoparticles
(Springer Heidelberg, 2023) İlkiner, Merve; Özay, Özgür
In this study, amphoteric hydroxyethyl starch/p([2(acryloyloxy)ethyl]trimethylammonium chloride-co-itaconic acid (HES/p(AETAC-co-IA) hydrogels containing both cationic and anionic groups in their structure were synthesized by the redox polymerization method. The synthesized hydrogels were modified with gold nanoparticles, and nanocomposite hydrogels were obtained. The characterizations of the nanocomposite HES/p(AETAC-co-IA)@Au hydrogels prepared for biomedical applications were carried out by SEM, TEM, FT-IR, TGA, and XRD techniques and swelling tests in simulated biological environments. Hydrogels designed as drug carrier cargo materials were loaded with sodium diclofenac (NaDcF) and ibuprofen drugs, and their release properties were studied. The release mechanisms and release kinetics of the two drugs were studied. The release kinetics determined for the drug NaDcF is consistent with the Higuchi model, while the release kinetics determined for ibuprofen is consistent with the first-order model. In addition, the antibacterial and antifungal properties of the hydrogels were tested. It was found that the HES/p(AETAC-co-IA)@Au hydrogel was effective against gram-positive Staphylococcus aureus, gram-negative Pseudomonas aeruginosa, and the fungal species Candida albicans.

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