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Öğe Concentration modulated skin marker for radiotherapy treatment planning process(ELSEVIER SCI LTD, 2013) Ozguven, Yildiray; Yucel, Birsen; Ozyurek, Betul; Karakus, Gulderen; Ozguven, YucelBackground and purpose: For conformal radiotherapy, it is feasible to achieve high accuracy in contouring the outline of the target volume in treatment planning process. In contouring process, target volume is occasionally defined by means of either surgical clips or skin marker during patient anatomical data acquisition. Treatment planning systems are predicting invalid radiation dose distributions by using surgical clips and skin marker within the patient. Purpose of this study is the production of new skin marker which affects less dose distributions of electron beam. Materials and methods: The influences of lead and commercial markers on dose calculations in a 3D treatment planning systems were investigated in terms of electron beam energy and dose profile depth. Dose deviation with commercial marker was observed to smaller than lead marker. However this dose deviation was still at big value. In order to reduce of this value, barium sulfate suspension and ultrasound gel were mixed with different volumetric ratio. With the purpose of acception the most suitable marker for radiation therapy, obtained new suspensions were investigated in terms of visibility and dose deviation. Results: B:G/1:10 marker was determined to cause optimum visibility and the lowest dose deviation on dose calculations in terms of electron beam energy and dose profile depth. Conclusions: Appropriate marker, mixture of substances such as barium sulfate suspension and ultrasound gel can be produced. This marker is both ease of usage and practical and economical. Each clinic can prepare marker which is peculiar to suspension with different concentration of substance for specific visibility. But, it should be taken into account resultant dose deviation to beam calculation depending on barium sulfate concentration. (C) 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.Öğe Cytotoxic effect of acriflavine against clinical isolates of Acanthamoeba spp(SPRINGER, 2013) Polat, Zubeyda Akin; Karakus, GulderenAcanthamoeba keratitis (AK) is a potentially devastating and sight-threatening infection of the cornea caused by the ubiquitous free-living amoebae, Acanthamoeba species. Its eradication is difficult because the amoebas encyst, making it highly resistant to anti-amoebic drugs. Acriflavine neutral (ACF) has been used for treatment of microbial infections for humans and fishes. The aim of our study was to evaluate the time-dependent cytotoxicities of ACF against Acanthamoeba spp. Trophozoites and cysts of three different strains (strain PAT06 Acanthamoeba castellanii, strain 2HH Acanthamoeba hatchetti, and strain 11DS A. hatchetti) of Acanthamoeba spp. were tested. All strains had been isolated from patients suffering from a severe AK. The effects of the ACF with the concentrations ranging from 15 to 500 mg mL(-1) on the cytotoxicity of Acanthamoeba strains were examined. ACF showed a time- and dose-dependent amebicidal action on the trophozoites and cysts. Pat06 (A. castellanii) was the most resistant, while strain 11DS (A. hatchetti) was the most sensitive. As a result, ACF could be concluded as a new agent for the treatment of Acanthamoeba infections. On the other hand, it still needs to be further evaluated by in vivo test systems to confirm the efficiency of its biological effect.Öğe Cytotoxicity of three maleic anhydride copolymers and common solvents used for polymer solvation(SPRINGER, 2013) Karakus, Gulderen; Zengin, Haci Bayram; Polat, Zubeyde Akin; Yenidunya, Ali Fazil; Aydin, SemihaThree maleic anhydride copolymers were synthesized by free-radical copolymerization. The synthesized products were named as follows: maleic anhydride-styrene (MAST); maleic anhydride-vinyl acetate (MAVA), and maleic anhydride-methyl methacrylate (MAMMA). Initiators used in the reactions were azobisisobutyronitrile (AIBN, 70 A degrees C, benzene) for MAST and benzoyl-peroxide [BPO, 80 A degrees C, methyl ethyl ketone (MEK)] for MAVA and MAMMA. Structural characterizations were carried out by Fourier transform infrared (FTIR) and nuclear magnetic resonance [H-1 NMR, C-13 NMR, and C-13-APT (attached-proton test)] spectrometry. Surface morphology was studied by scanning electron microscopy (SEM). Solubility of the copolymers was examined in water and in twelve different organic solvents. Cytotoxicity of the copolymers and the solvents was evaluated by using a mouse fibroblast cell line (L929), copolymers had almost no toxicity. Of the twelve organic solvents, acetone, MEK, and tetrahydrofuran (THF) produced the least toxicity. MEK was found to be the best solvent and used for the solvation of the copolymers.Öğe Derivatization of Some Maleic Anhydride Containing Copolymers with Amine Functionalized Pharmaceutical Active Substances, Structural Characterizations and Biological Activities(MARMARA UNIV, FAC PHARMACY, 2015) Karakus, GulderenPoly(maleic anhydride-co-styrene) (MAST), poly(maleic anhydride-co-vinyl acetate) (MAVA), poly(maleic anhydride-co-methyl methacrylate) (MAMMA), poly(maleic anhydride-co-allyl phenyl ether) (MAAFE) and poly(maleic anhydride-alt-acrylic acid) (MAAA) copolymers were synthesized by free radical chain polymerization reaction. Modification/derivatization of the copolymers with active pharmaceutical ingredients, in amine form (-NH2), was performed by the ring opening reaction. Structural characterization of the copolymers and the conjugated products was carried out by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (H-1-NMR). The FTIR and H-1-NMR spectra, confirmed that pharmaceutically active agents were covalently bonded to the MAVA copolymer in a succesfull manner. Furthermore cytotoxicity on healthy fibroblast cell lines, antiproliferative activity on cancer cell lines and antibacterial activity on bacterial strains were also investigated in-vitro for synthesized conjugates. MAVA copolymer was also selected the most suitable carrier for modification/derivaritization process by comparing its affinity to the pharmaceutically active agents.Öğe Design, fabrication and characterization of silane tailored surface of halloysite based polymer nanocomposites(Wiley, 2023) Uner, Gizem; Karakus, Gulderen; Can, Hatice KaplanIn recent years, polymeric drug conjugates, nanoparticles, nanocapsules, liposomes, micelles, dendrimers, and nanogels have been gained a great attention. Organically modified layered nanoclays have become an attractive hybrid biomaterial due to their wide range of uses, which can be designed with desired properties in a wide variety of applications from industry to medicine. Functional water-soluble poly(maleic anhydride-alt-acrylic acid) [poly(MA-alt-AA)], synthesized in our previous study, was chosen for the prepare of halloysite/polymer nanocomposite. Surface modification of halloysite nanotubes (HNTs) with 3-aminopropyltriethoxysilane (APTS) was performed to obtain organic functionalized halloysite and also for better compatibility of nanotubes (NTs) with monomers. Nanocomposite were obtained by in situ solution complex-radical copolymerization via charge transfer complex under conditions of copolymerization, using pristine and APTS functionalized HNTs, acrylic acid (AA), and maleic anhydride (MA) monomers. Optimization study using different clay ratios and recipe for organic-inorganic compatibility also were carried out. Characterization studies of halloysite, modified halloysite, copolymers and the formed copolymer-HNT nanotubes were enlighten by using spectroscopic analyzes such as, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), High resolution Raman (HR-Raman), X-Ray Diffraction Measurements (XRD) and X-Ray Photoelectron Spectroscopy (XPS). Thermal analysis and dynamic mechanical properties were performed with Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA), respectively. Surface morphology was also carried out by Transmission Electron Microscopy (TEM). In the light of these detailed analysis results, it can be briefly concluded that surface modification of HNT, synthesis of copolymer/HNT nanocomposites, and structural characterization successfully achieved.Öğe Design, fabrication, and characterization of o-phenylenediamine surface-conjugated carbon quantum nanodots as a potential new bioactive formulation(Springer Science and Business Media Deutschland GmbH, 2023) Karakus, GulderenThe aim of this study was to design and characterize a candidate molecule of biological significance by synergistically combining the unique chemical properties, biocompatibility, and low toxicity of carbon quantum dots (CNDs) by the precursor molecule o-phenylenediamine (o-PDA), which is used to produce most chemotherapeutic agents, as a CNDs/o-PDA conjugate. Using citric acid (CA), surface-functional CNDs were synthesized by simple and rapid thermal pyrolysis for 2 h at 180 °C without using chemicals. Conjugation was carried out for 16 h at 40 °C in N,N-dimethylformamide (DMF) presence of triethylamine (Et3N). Structural characterizations were performed by spectroscopic techniques such as attenuated total reflectance—Fourier transform infrared (ATR-FTIR), nuclear magnetic resonance (1H-NMR), UV–Vis, and fluorescence spectroscopy. The crystal structure of pure- and o-PDA-conjugated-CNDs was characterized using X-ray diffractometers (XRD-MF). Physical characterizations were performed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Q-TOF LC/MS (liquid chromatography–quadrupole-time-of-flight mass spectrometry) and size exclusion chromatography (SEC) were used to analyze molecular weight change and polydispersity index (PDI) as a result of o-PDA conjugation. The spherical nanoparticle size of the nanodots was confirmed by transmission electron microscopy (TEM). All results suggest that the targeted o-PDA derivatization of CNDs was successfully achieved by the ring-opening reaction. © 2023, King Abdulaziz City for Science and Technology.Öğe Design, Synthesis and Characterization of 1,2-Phenylenediamine Functionalized Poly (Maleic Anhydride-alt-Vinyl Acetate) as a Potential New Bioactive Formulation(2022) Karakus, GulderenThis study includes the design, synthesis and characterization of 1,2-phenylenediamine (o-PDA) functionalized maleic anhydride (MA)-vinyl acetate (VA) copolymer-based conjugate to develop a new formulation. The phenylenediamine molecule is a fluorescent dye that allows designing new chemotherapeutic polymeric molecules. Poly(maleic anhydride-alt-vinyl acetate) [Poly(MA-alt-VA)] was obtained via charge transfer complex (CTC) radical polymerization presence of methyl ethyl ketone (MEK), utilizing benzoyl peroxide (BPO) free-radical initiator at 80 °C, as a potential functional polymeric carrier. Structural characterization of the surface functionalized poly(MA-alt-VA)/1,2-PDA conjugate was performed by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) and Nuclear Magnetic Resonance (1H-NMR). Spectroscopic methods and water solubility results confirmed that the conjugation took place successfully after the ring opening reaction by the amide mechanism.Öğe The effects of therapeutic x-ray doses on mechanical, chemical and physical properties of poly methyl methacrylate(INFORMA HEALTHCARE, 2013) Dogan, Derya Ozdemir; Ozguven, Yildiray; Karakus, Gulderen; Sahin, Onur; Polat, Nilufer Tulin; Yucel, Birsen; Dogan, MansurAim. The aim of this study was to investigate the effect of radiation doses very close to the human dose for oral cancers on mechanical, chemical and physical properties for poly methyl-methacrylate (PMMA). Methods. PMMA samples were divided into four different groups: no irradiated group, 25-Gy irradiated group, 50-Gy irradiated group and 75-Gy irradiated group. Each group contained nine samples. After 24 h, a three-point loading test was applied to each PMMA groups. The transverse strength and the elastic modulus were calculated using the test results. The results were analyzed statistically by using one-way analysis of variance. The structural characterizations of the PMMA samples were carried out by a Fourier Transform Infrared (FTIR) spectrophotometer to evaluate the chemical structure differences. Results. The transverse strength values of 25-Gy, 50-Gy and 75-Gy radiation groups were significantly higher than that of the no radiation group (p < 0.05). There was no significant difference among the elastic modulus values of the study groups (p > 0.05). The FTIR findings demonstrated that the irradiation process did not change the chemical structure of the PMMA polymeric materials. Conclusion. The therapeutic radiation doses increase the mechanical properties of the PMMA; however, the chemical and structural properties have no effect. When the findings of this study are taken into account, it can be said that patients can wear dentures during the radiotherapy.Öğe Evaluation of antiproliferative and antimicrobial activity of polyanhydride based poly[(maleic anhydride)-co-(vinyl acetate)]/noradrenaline conjugate(2024) Tunc, Tutku; Karakus, GulderenAim: Personalized medicine has increased the interest in polymer-drug conjugates. In recent years, many polymer-drug conjugates have been developed to increase the specificity and selectivity of drugs for diseases. Noradrenaline (NA) is involved in the pathophysiology of many different neurological, psychiatric, and peripheral conditions. Moreover, NA has been reported to play a role in angiogenesis and tumor development. The MAVA/NA conjugate, a maleic anhydride-vinyl acetate (MAVA) copolymer modification product, and the noradrenaline biomolecule were examined for their antiproliferative and antimicrobial properties. Materials and Methods: MAVA-NA conjugate was synthesized as the modification product between maleic anhydride-vinyl acetate (MAVA) copolymer and noradrenaline (NA) biomolecule. The conjugate was previously characterized in terms of chemical structure by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) spectroscopic methods, and its topographic properties were characterized by atomic force microscopy (AFM). The minimum inhibitory concentration (MIC) method evaluated the antimicrobial properties against gram-positive and gram-negative bacteria and fungi. Antiproliferative activity was determined by XTT assay on lung (A549), brain (C6), bone (MG-63), and breast (MCF-7) cancer cells and healthy fibroblast (WI-38) cell lines. Results: The MAVA-NA conjugate showed no toxicity within the 3.125-100 µg/mL dosage range in WI-38 cells. Compared to normal fibroblast cells, MAVA-NA exhibited selective toxicity against A549, C6, MG-63, and MCF-7 cancer cells. MAVA-NA showed high antibacterial activity on S. aureus and MRSA bacteria compared to standard antibiotics (S. aureus MIC=50 µg/mL, MRSA MIC=25 µg/mL). Conclusion: These results indicate that the newly synthesized and characterized MAVANA conjugate has antiproliferative and antimicrobial effects and may have a promising role in developing new anticancer drugs.Öğe Investigation of Cytotoxic and Antimicrobial Effects of Polyanhydride-Based Poly[(maleic anhydride)-co-(vinyl Acetate)] Conjugates Combined with Methotrexate and Gemcitabine in Breast Cancer Treatment(Amer Chemical Soc, 2025) Tunc, Tutku; Karakus, Gulderen; Sumer, ZeynepStudies aimed at increasing the efficacy of chemotherapeutic drugs and reducing or completely eliminating their side effects are frequently encountered. In our study, we considered methotrexate (MTX), which is in the category of anticarcinogenic and anti-inflammatory drugs, and gemcitabine (GEM), which is used in the treatment of breast, testicular, ovarian, etc. cancers. GEM, which is used in the treatment of breast, testicular, ovarian, etc. cancers, was covalently bonded to maleic anhydride vinyl acetate (MAVA) copolymer, and new polymer-drug conjugates (MAVA-MTX and MAVA-GEM) were obtained to reduce or eliminate the side effects of these drugs and to investigate the cytotoxic and antimicrobial effects of the new conjugates. The conjugation reaction was carried out in the presence of a triethylamine catalyst in dimethylformamide medium at 70 degrees C. Chemical structure elucidation of the copolymer (MAVA) and conjugates (MAVA-MTX and MAVA-GEM) was carried out by Fourier transform infrared (FTIR) and Nuclear Magnetic Resonance (1H NMR) spectroscopy. Anticancer activity was determined by the MTT assay in MCF-7 (breast cancer), and L929 (mouse fibroblast) cell lines. The synthesized copolymer and conjugate structures were proved by FTIR and 1H NMR spectra. It was determined that the conjugates did not form an inhibition zone on the test microorganisms. MIC values were found to be moderately effective compared with reference sources. The anticancer activities of MAVA-MTX and MAVA-GEM conjugates were significantly higher than those of methotrexate and GEM. The higher anticancer activity of the synthesized MAVA-MTX and MAVA-GEM conjugates compared with the drug they contain suggests that they can be a potential drug candidate in the treatment of breast cancer. In addition, the conjugates showed less toxic effect on a healthy L929 cell line at 6 different concentrations compared to free drugs. This can be shown as a significant improvement in reducing one of the most important side effects of the drug, such as toxicity.Öğe Modification of Maleic Anhydride-Styrene Copolymer with Noradrenaline by Chemical and Enzymatic Methods(WILEY-BLACKWELL, 2011) Karakus, Gulderen; Yenidunya, Ali Fazil; Zengin, Haci Bayram; Polat, Zubeyde AkinMaleic anhydride copolymer was modified with another biologically active agent, noradrenaline (NA), using both chemical and enzymatic methods. The modification and synthesized products were named as follows: chemical modification, MASTNAc; enzymatic modification, MASTNAe; enzymatically synthesized MASTNA from individual monomers, MASTNAem. Chemical and enzymatic reactions were performed at 70 degrees C and 38 degrees C, respectively. In the chemical reactions azobisisobutyronitrile was used as the initiator. In the enzymatic reactions, an extracellular extract, including an enzyme with peroxidase-like activity, was used. All the reactions were performed in an organic medium, methyl ethyl ketone. Structural characterization of the copolymer and modified copolymer were carried out by Fourier transform infrared (FTIR) and nuclear magnetic resonance ((1)H NMR). FTIR and (1)H NMR spectra confirmed that NA was successfully covalently bound onto the MAST copolymer backbone by both chemical and enzymatic methods. Surface morphology of the samples was studied by scanning electron microscopy. Results obtained indicated that chemical and enzymatic addition of NA to MAST backbone yielded products having quite similar physical and chemical properties. On the other hand, MASTNA-modified copolymer synthesized by individual monomers appeared to be different in its chemical structure. Furthermore, enzymatic modification and synthesis appeared to provide a good alternative method because it required much milder conditions such as low temperature, and better product qualities: higher solubility in water, higher yield and purity. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2821-2828, 2011Öğe Sequential determination of serum viral titers, virus-specific IgG antibodies, and TNF-alpha, IL-6, IL-10, and IFN-gamma levels in patients with Crimean-Congo hemorrhagic fever(BIOMED CENTRAL LTD, 2014) Kaya, Safak; Elaldi, Nazif; Kubar, Ayhan; Gursoy, Nevcihan; Yilmaz, Meral; Karakus, Gulderen; Gunes, Turabi; Polat, Zubeyde; Gozel, Mustafa Gokhan; Engin, Aynur; Dokmetas, Ilyas; Bakir, Mehmet; Yilmaz, Neziha; Sencan, MehmetBackground: Although there have been a number of studies on the pathogenesis of Crimean-Congo hemorrhagic fever (CCHF) recently, knowledge on this topic is still insufficient. This study aims to reveal the kinetics of serum CCHF virus (CCHFV) titers, serum levels of anti-CCHFV immunoglobulin (Ig) G, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-10, and interferon (IFN)-gamma in CCHF patients. Methods: In total, 31 CCHF cases (11 fatal) were studied. Serum samples were obtained daily from all patients from the time of admission and continued for a 7-day hospitalization period for serologic (ELISA), virologic (real-time PCR), and cytokine (ELISA) analysis. Results: The mean serum CCHFV titer at admission was 5.5E + 09 copies/mL in fatal cases and 5.7E + 08 copies/mL in survivors (p < 0.001). Compared to survivors, both the mean serum levels of IL-6 and TNF-alpha at admission were found to be significantly increased in fatal cases. The serum levels of IL-6, TNF-alpha and serum CCHFV titer at admission were significantly and positively correlated with disseminated intravascular coagulation (DIC) scores (r = 0.626, p = 0.0002; r = 0.461, p = 0.009; and r = 0.625, p = 0.003, respectively). When the data obtained from the sequential determination of CCHFV titer and levels of anti-CCHFV IgG, IL-6, TNF-alpha, IL-10 and IFN-gamma were grouped according to the days of illness, the initial serum CCHFV titer of a fatal patient was 5.5E + 09 (copies/mL) and it was 6.1E + 09 (copies/mL) in a survivor on the 2 day of illness. While significant alterations were observed in all cytokines during the monitoring period, IL-6 levels remained consistently higher in fatal cases and TNF-alpha levels increased in both in fatal and non-fatal CCHF cases. Conclusions: The increased CCHFV load and higher concentrations of IL-6 and TNF-alpha, the presence of DIC, and the absence of CCHFV specific immunity are strongly associated with death in CCHF.Öğe Silver Nanoparticles Capped with Poly[(maleic anhydride)-co-(vinyl acetate)](2023) Ayas, Gamze; Karakus, GulderenAnhydride containing functional co-polymer, Poly[(maleic anhydride)-co-(vinyl acetate)] (pMAVAc) was synthesized by free radical polymerization reaction presence of methyl ethyl ketone (MEK) media with benzoyl peroxide radical initiation at 80 ?C. Surface modification of pMAVAc was carried out with silver to obtain size specific silver nanocomposites by well-known chemical-reduction approach. Structural characterizations of the samples were performed spectroscopic measurement and surface morphology identification using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM), respectively. Results obtained from the ATR-FTIR analysis, detection of the characteristic spectrum data of the co-polymer composition in pMAVAc-AgNPs nanocomposite is proof that the co-polymer structure remains unchanged after treatment. The size and morphological properties of the silver nanoparticles were compatible with the characteristic nanomaterial structure and their average size was found to be 35 nm. In addition, as expected, MAVA-AgNPs nanocomposite, the detection of 79.73% Ag by mass is evidence of the high silver content in the material, and it was concluded that the co-polymer was successfully coated with silver. In recent years, considering the increasing importance of biocompatible nanomaterials in drug delivery systems and in pharmaceutical industry, the synthesized nanocomposites are thought to be a useful drug carrier system with potential antibacterial activity.Öğe Synthesis, characterization and antiproliferative activities of novel modified poly (maleic anhydride-co-vinyl acetate)/cytosine beta-D-arabinofuranoside hydrochloride conjugate(MARMARA UNIV, FAC PHARMACY, 2015) Karakus, Gulderen; Yaglioglu, Ayse Sahin; Zengin, Haci Bayram; Karakus, NihatPoly (maleic anhydride-co-vinyl acetate) (MAVA) copolymer was synthesized by free-radical-polymerization reaction in methyl ethyl ketone (MEK) at 80 degrees C using benzoyl-peroxide (BPO) as the radical-initiator. MAVA was then modified with anti-leukemic chemotherapy-agent cytosine beta-D-arabinofuranoside hydrochloride (CF). Modification was performed at 70 degrees C in dimethylformamide (DMF) containing triethylamine (Et3N) as the catalyst. Structural characterization of the copolymer and copolymer/drug couple (MAVA/CF) was carried out by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (H-1-NMR). FTIR and H-1-NMR spectra confirmed the modification reaction. UV-Spectrophotometric measurements indicated that MAVA/CF kept its molecular integrity in physiological-body-fluid, PBS, for first four days. Antiproliferative activities of MAVA/CF were also determined by BrdU-cell-proliferation-ELISA assays using C6 and HeLa cell lines (cisplatin and 5-fluorouracil used as positive control). MAVA/CF appeared to have little antiproliferative activity against C6 cell line while samples didn't have antiproliferative activity against HeLa cell line at low concentrations (<100 mu g/ml). Reaction mechanism was also recommended for modification product MAVA/CF.Öğe Synthesis, characterization and cytotoxicity of novel modified poly[(maleic anhydride)-co-(vinyl acetate)]/noradrenaline conjugate(WILEY-BLACKWELL, 2013) Karakus, Gulderen; Polat, Zubeyde Akin; Yenidunya, Ali Fazil; Zengin, Haci Bayram; Karakus, Can BulentPoly[(maleic anhydride)-co-(vinyl acetate)] (MAVA) copolymer was synthesized by free radical polymerization reaction, in methyl ethyl ketone at 80 degrees C, using benzoyl peroxide as the initiator. The copolymer was then modified with a biomolecule, noradrenaline (NA). The modification reaction was performed at 70 degrees C in dimethylformamide containing triethylamine as the catalyst. The modified polymer was named MAVA/NA. Structural characterization of the copolymer and the modified product was carried out by Fourier transform infrared (FTIR) and 1H NMR and 13C NMR spectroscopy. The FTIR, 1H NMR and 13C NMR spectra confirmed that NA was successfully covalently bound to the MAVA copolymer backbone. Surface morphology was visualized by atomic force microscopy. The cumulative release of NA from MAVA/NA was determined in phosphate buffered saline solution for 7 days at 37 degrees C and compared with MAVA. Cytotoxicity of the MAVA/NA was evaluated by using a mouse fibroblast cell line (L929). Results obtained indicated that MAVA/NA had almost no toxicity and no negative effect on cell viability at 250 mu g mL1 concentration. (c) 2012 Society of Chemical IndustryÖğe Synthesis, characterization and in vitro antibacterial assessments of a novel modified poly[maleic anhydride-alt-acrylic acid]/acriflavine conjugate(SPRINGER, 2014) Can, Hatice Kaplan; Karakus, Gulderen; Tuzcu, NevinWater-soluble maleic anhydride-containing poly[maleic anhydride-alt-acrylic acid] (poly(MA-alt-AA) or MAAA) copolymer was synthesized by freer-adical chain polymerization reaction, in 1,4-dioxane in the presence of benzoyl peroxide, 0.1 %, as the radical initiator at 70 degrees C under a nitrogen atmosphere. The purified copolymer was then modified with an anti-external fungal and anti-cancer active agent, acriflavine (AF). The modification reaction was performed 48 h at 70 degrees C in dimethylformamide organic media, using triethylamine (TEA or Et3N) as the catalyst. The modified or conjugated copolymer/drug couple was named as MAAA/AF. Detailed structural characterization of the copolymer (MAAA) and modified product (MAAA/AF) was carried out by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (H-1-NMR and C-13-NMR). The obtained FTIR, H-1-NMR, and C-13-NMR spectra confirmed that AF was successfully bound to the MAAA copolymer backbone by ring-opening reaction. Antimicrobial susceptibility of the MAAA, AF, and MAAA/AF was evaluated by Kirby Bauer Disc Diffusion method on Mueller-Hinton Agar using Enterecoccus faecium, Enterohaemorrhagic Escherichia coli (EHEC), Staphylococcus aureus and Listeria monocytogenes. Results obtained indicated that MAAA/AF had antibacterial activity on EHEC and S. aureus at 50, 40, and 30 mu g. A mechanism for MAAA and AF was then also suggested for the conjugation reaction.Öğe Synthesis, characterization, and assessment of cytotoxic, antiproliferative, and antiangiogenic effects of a novel procainamide hydrochloride-poly(maleic anhydride-co-styrene) conjugate(TAYLOR & FRANCIS LTD, 2013) Karakus, Gulderen; Polat, Zubeyde Akin; Yaglioglu, Ayse Sahin; Karahan, Mesut; Yenidunya, Ali FazilPoly(maleic anhydride-co-styrene) (MAST) was synthesized by a free-radical polymerization reaction. A bioactive molecule, procainamide hydrochloride (PH), was then conjugated to MAST. The conjugation product was named as MAST/PH. Structural characterization of MAST and MAST/PH was carried out by Fourier Transform Infrared and Nuclear Magnetic Resonance spectroscopy. Their molecular weights were determined by size-exclusion chromatography. A mechanism was then suggested for the conjugation reaction. The results of the cytotoxicity assay, employing a mouse fibroblast cell line (L929), indicated that MAST/PH had no cytotoxicity at concentrations 62gmL(1) (p>0.05). Antiproliferative activities of MAST/PH and PH were determined by the BrdU cell proliferation ELISA assay, using C6 and HeLa cell lines. In the experiment, two anticancer chemotherapy drugs, cisplatin and 5-fluorouracil, were included as positive control. Antiproliferative activity results demonstrated that MAST/PH yielded the highest suppression profile (approximately 42%) at 20g/ml, while free PH exerted the same activity at 100g/ml. Interestingly, both MAST/PH and PH suppressed the proliferation of only one of the cell lines, C6 cells. Both cisplatin and 5-fluorouracil yielded approximately 60% antiproliferative activity on C6 cells at 20 and 100g/ml concentrations. Antiangiogenic capacity of both MAST and MAST/PH was also investigated by using the chicken chorioallantoic membrane assay. Results obtained indicated that while MAST/PH could be included into the category of good antiangiogenic substances, the activity score of MAST was within the weak category.Öğe Synthesis, structural characterization, and antiproliferative/cytotoxic effects of a novel modified poly(maleic anhydride-co-vinyl acetate)/doxorubicin conjugate(SPRINGER, 2017) Karakus, Gulderen; Ece, Abdulilah; Yaglioglu, Ayse Sahin; Zengin, Haci Bayram; Karahan, MesutDrug carrier, poly(maleic anhydride-co-vinyl acetate) (MAVA or poly[MA-co-VA]) copolymer, was traditionally synthesized by free radical chain polymerization reaction, in methyl ethyl ketone (MEK) organic media at 80 A degrees C, using benzoyl peroxide (BPO) as the radicalic initiator. The purified copolymer was then modified with a chemotherapeutic agent, doxorubicin hydrochloride (DOX) at 75 A degrees C for 72 h, using N-(3-dimethyl-aminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC) as the carboxylic acid-activating agent. Structural characterization of the MAVA and the modified MAVA/DOX conjugate was carried out by Fourier transform infrared (FTIR) and nuclear magnetic resonance (H-1-NMR and C-13-NMR). Their molecular weights were determined by size-exclusion chromatography (SEC). The spectroscopic and SEC results confirmed that conjugated/modification reaction was successfully carried out. UV spectrophotometric measurements indicated that MAVA/DOX preserved its molecular stability in physiological body fluid, PBS (physiological pH 7.40 at 37 A degrees C). Antiproliferative activities of MAVA/DOX were determined by BrdU cell proliferation ELISA assay using C6 (Rat Brain tumor cells) and HeLa (human uterus carcinoma) cell lines in vitro by comparing with free DOX agent (reference compound). Although MAVA showed low antiproliferative activity, both MAVA/DOX and DOX exhibited greater activity against HeLa and C6. Lactate dehydrogenase (LDH) leakage assay was performed for MAVA/DOX and DOX, which detected a non-toxic effect against C6 even at the highest dose (100 mu g/mL). IC50 and IC75 values were also determined using ED50 plus v1.0. Molecular modeling at M06-L/6-31 + G(d,p)//AM1 level showed that the electron density in MAVA/DOX is more localized resulting a higher polarization and thereby a higher dipole moment which shed light on the solubility of MAVA/DOX conjugate.Öğe Synthesis, structural characterization, thermal behavior and cytotoxic/antiproliferative activity assessments of poly(maleic anhydride-alt-acrylic acid)/hydroxyurea polymer/drug conjugate(Elsevier, 2020) Karakus, Gulderen; Can, Hatice Kaplan; Yaglioglu, Ayse SahinAs drug carrier, poly(maleic anhydride-alt-acrylic acid) copolymer [poly(MA-alt-AA)], was prepared traditionally by radical initiated (benzoyl peroxide (BPO)), complex-radical polymerization technique via charge transfer complex (CTC) (50/50 in p-dioxane, at 70 degrees C under a nitrogen atmosphere). The pure alternating carrier was then conjugated as poly[MA-alt-AA]/HX (or MAAA/HX) copolymer/drug couple by ring opening reaction with an antineoplastic agent hydroxyurea (HX) for 48 h at 75 +/- 0.1 degrees C in dimethylformamide (DMF), presence of triethylamine (Et3N) catalytic base. Chemical structure of the copolymer, antineoplastic agent and conjugate was characterized by Fourier Transform Infrared (ATR-FTIR) and also Nuclear Magnetic Resonance (proton and carbon NMR). Physical characterizations were also carried out by Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). To verify the elemental composition and also conjugation reaction of conjugated product, quantitative elemental analysis was especially carried out. Cytotoxicity was determined with Lactate Dehydrogenase (LDH) leakage assay using LDH cytotoxicity detection kit provided by Roche Diagnostics GMBH (Mannheim, Germany) based on the protocol in the user's manual. Compared with 5-FU, toxicity values are as follows respectively: HX > MAAA > 5-FU. MAAA/HX. Furthermore, antiproliferative activity studies was examined on HeLa (human cervical cancer) and (C6) rat brain tumor cells using proliferation BrdU ELISA assay. Conjugated-drug was identified to have the higher antiproliferation than the copolymer and free-drug (Hydroxyurea) on all studied concentrations and cellular potency of inhibitions were found as MAAA/HX > HX > MAAA at the highest concentration, 100 mu g/mL. Toxic drug (HX) was modified as nontoxic MAAA/HX conjugate with good properties. (C) 2020 Elsevier B.V. All rights reserved.
