Browsing by Author "Bayram, Cem"

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Chondrogenesis of human mesenchymal stem cells by microRNA loaded triple polysaccharide nanoparticle system
(2019) Celik, Ekin; Bayram, Cem; Denkbas, Emir Baki; 31147048
Degenerative cartilage is the pathology of severe depletion of extracellular matrix components in articular cartilage. In diseases like osteoarthritis, misregulation of microRNAs contributes the pathology and collectively leads to disruption of the homeostasis. In this study chondroitin sulfate/hyaluronic acid/chitosan nanoparticles were prepared and successfully characterized chemically and morphologically. Results demonstrated higher chondroitin sulfate amounts led smaller nanoparticles, but lower surface zeta potential due to high electronegativity. After optimization of chondroitin sulfate amounts regarding size and charge, nanoparticles were loaded with microRNA-149-5p, a therapeutic miRNA downregulated in osteoarthritis, and evaluated focusing on their loading efficiency, release behaviour, cytotoxicity and gene transfection efficiency in vitro. Results showed all nanoparticle formulations were non-toxic and promising gene delivery agents, due to increased levels of microRNA-149-5p and decreased mRNA levels of microRNA's target, FUT-1. Highest gene transfection efficiency was obtained with the nanoparticle formulation which had the highest chondroitin sulfate load and smallest size. In addition, owing to their high chondroitin sulfate cargo, all nanoparticles were reported to enhance chondrogenesis, which was demonstrated by gene expression analysis and sulfated glycosaminoglycan (sGAG) staining. The obtained data suggest that the delivery of microRNA-149-5p via polysaccharide based carriers could achieve collaborative impact in cartilage regeneration and have a potential to enhance osteoarthritis treatment.
Effect of argon plasma and Er:YAG laser on tensile bond strength between denture liner and acrylic resin
(2020) Yildirim, Arzu Zeynep; Unver, Senem; Mese, Ayse; Bayram, Cem; Denkbas, Emir Baki; Cevik, Pinar; 33039186
Statement of problem. The separation of a denture liner from the denture base can be a clinical problem. Different surface treatments to increase the bond have been evaluated, but studies comparing the effect of argon plasma and erbium-doped yttrium aluminum garnet (Er:YAG) laser on the bond between acrylic resin and a denture liner are lacking. Purpose. The purpose of this in vitro study was to evaluate the effect of argon plasma and Er:YAG laser treatments on the bond strengths of acrylic resin to 2 denture liners. Materials and methods. Heat-polymerized acrylic resin (Acron Duo) was bonded to silicone soft-liner materials (Molloplast B, n=30; Mollosil, n=30) to create control specimens (n=10), argon plasma treatment (n=10), and Er:YAG laser treatment (n=10). Silicone liners were polymerized on resin specimens. The tensile bond strength test was performed with a crosshead speed of 10 mm/min with a 10-N load until failure. Data were analyzed by using the Kruskal-Wallis test and unpaired t test (alpha=.05). Results. The laser group showed significantly higher bond strength than the argon plasma group for both Molloplast-B (P=.001) and Mollosil (P<.001). The highest tensile bond strength values were determined in the laser-treated Molloplast-B group (1.325 +/- 0.119 MPa) while the lowest bond strength values were determined in the Mollosil control group (0.384 +/- 0.018 MPa). Conclusions. Argon plasma and Er:YAG laser applications increases the tensile bond strength between soft-liner material and resin. Er:YAG laser treatment results in higher bond strength values than treatment with argon plasma for 1 minute.
Magnetically responsive, sorafenib loaded alginate microspheres for hepatocellular carcinoma treatment
(2020) Alpdemir, Sukran; Vural, Tayfun; Kara, Goknur; Bayram, Cem; Haberal, Erdem; Denkbas, Emir Baki; 0000-0003-2788-550X; 33010138; ABC-8833-2020
This study aimed to develop sorafenib loaded magnetic microspheres for the treatment of hepatocellular carcinoma. To achieve this goal, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesised and encapsulated in alginate microspheres together with an antineoplastic agent, sorafenib. In the study, firstly SPIONs were synthesised and characterised by dynamic light scattering, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Then, alginate-SPIONs microspheres were developed, and further characterised by electron spin resonance spectrometer and vibrating sample magnetometer. Besides the magnetic properties of SPIONs, alginate microspheres with SPIONs were also found to have magnetic properties. The potential use of microspheres in hyperthermia treatment was then investigated and an increase of about 4 degrees C in the environment was found out. Drug release studies and cytotoxicity tests were performed after sorafenib was encapsulated into the magnetic microspheres. According to release studies, sorafenib has been released from microspheres for 8 h. Cytotoxicity tests showed that alginate-SPION-sorafenib microspheres were highly effective against cancerous cells and promising for cancer therapy.
Porous polyurethane film fabricated via the breath figure approach for sustained drug release
(2019) Daha, Gizem; Bayram, Cem; Bozdogan, Betuel; Denkbas, Emir Baki
The breath figure (BF) method is an effective process for fabricating porous polymeric films. In this study, we fabricated porous polymer films from thermoplastic polyurethane (PU) through static BF with CHCl3 as a solvent under 55-80% relative humidity. The porous PU films were prepared within various pore structures and sizes, which were adjustable, depending on the fabrication conditions. The humidity and exposure time were examined as variable parameters affecting the surface morphology, wettability, and cytotoxicity. Atorvastatin calcium, a hyperlipidemic agent, was loaded into the porous films during the casting process, and the drug-loading and drug-releasing behaviors of the porous PU membranes were evaluated. Approximately 60-80% of the drug was released in 14 days. The films exhibited sustained drug-release performances because of the hydrophobicity and nonbiodegradable nature of PU for perivascular drug administration. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47658.