Browsing by Author "Denkbas, Emir B."

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    Bacterial hyaluronic acid production through an alternative extraction method and its characterization
    (2019) Gungor, Gokhan; Gedikli, Serap; Toptas, Yagmur; Akgun, Dilber E.; Demirbilek, Murat; Yazihan, Nuray; Celik, Pinar Aytar; Denkbas, Emir B.; Cabuk, Ahmet
    BACKGROUND In this study, hyaluronic acid (HA) was produced using Streptococcus equi ssp. equi via an optimized Central Composite Design process, with purification by an alternative extraction method. Determinations of molecular weight, cytotoxicity, viscosity; proton nuclear magnetic resonance (H-NMR) and Fourier transform infrared-attenuated total reflection (FTIR-ATR) analyses were provided. RESULTS The HA yield obtained was up to c. 12 g L-1 under the reaction conditions of pH 7.8, 33 degrees C incubation temperature, 24 h incubation time and 187 rpm agitation rate. According to gel permeation chromatography results, HA has an average molecular weight of 79 416 Da. FTIR-ATR analysis showed that the spectrum of the standard HA sample overlapped with the spectrum obtained from this study. CONCLUSION In this study, higher titer production of HA was obtained with a simple and economical sequential process. Additionally, the results indicate that the HA produced is an appropriate biomaterial for medical applications. (c) 2019 Society of Chemical Industry
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    Prevention of urinary infection through the incorporation of silver-ricinoleic acid-polystyrene nanoparticles on the catheter surface
    (2021) Koc, Hazal; Kilicay, Ebru; Karahaliloglu, Zeynep; Hazer, Baki; Denkbas, Emir B.; 33530824
    Nosocominal infections associated with biofilm formation on urinary catheters cause serious complications. The aim of this study was to investigate the feasibility of the polyurethane (PU) catheter modified with tetracycline hydrochloride (TCH) attached Ag nanoparticles embedded PolyRicinoleic acid-Polystyrene Nanoparticles (PU-TCH-AgNPs-PRici-PS NPs) and the influence on antimicrobial and antibiofilm activity of urinary catheters infected by Escherichia coli and Staphylococcus aureus. For this purpose, AgNPs embedded PRici graft PS graft copolymers (AgNPs-PRici-g-PS) were synthesized via free radical polymerization and characterized by FTIR, HNMR and DSC. AgNPs-PRici-PS NPs were prepared and optimized by the different parameters and the optimized size of nanoparticle was found as about 150 +/- 1 nm. The characterization of the nanoparticles and the morphological evaluation were carried out by FTIR and SEM. Short term stability of nanoparticles was realised at 4 degrees C for 30 days. In vitro release profiles of TCH and Ag NPs were also investigated. The formation of biofilm on PU modified TCH-Ag NPs-PRici-PS NPs, was evaluated and the biocompatibility test of the nanoparticles was realized via the mouse fibroblast (L929) and mouse urinary bladder cells (G/G An1). This is the first time that TCH-AgNPs-PRici-PS NPs used in the modification of PU catheter demonstrated high antimicrobial and antibiofilm activities against the urinary tract infection.