Person: TOKSOY ÖNER, EBRU
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TOKSOY ÖNER
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Publication Metadata only Investigation of anti-cancer activity of linear and aldehyde-activated levan from Halomonas smyrnensis AAD6(T)(ELSEVIER, 2014) TOKSOY ÖNER, EBRU; Sarilmiser, Hande-Kazak; Oner, Ebru ToksoyThe main aim of this study was to investigate the potential role of levan polysaccharide in developing polysaccharide-based anticancer therapeutics. Moreover, by periodate oxidation, chemically modified forms of levan harboring increasing amounts of aldehyde groups were obtained and characterized. All the samples were found to be biocompatible when treated with the mouse fibroblast cell line L929. Anticancer activities of levan and its derivatives were investigated in A549 (human lung adenocarcinoma), HepG2/C3A (human liver hepatocellular carcinoma), AGS (human gastric adenocarcinoma), and MCF-7 (human breast adenocarcinoma) cell lines and were found to depend on the dose as well as on the cell type. The observed decrease in cancer cell viability was shown to be due to apoptosis via luminogenic-based caspase-3/7 activity assay. This study established the high potential of these levan-based polymers in developing polysaccharide-based nanocarrier systems for anti-cancer drugs. (C) 2014 Elsevier B.V. All rights reserved.Publication Metadata only Lecithin-acrylamido-2-methylpropane sulfonate based crosslinked phospholipid nanoparticles as drug carrier(WILEY, 2016) TOKSOY ÖNER, EBRU; Mutlu, Esra Cansever; Bostan, Muge Sennaroglu; Bahadori, Fatemeh; Kocyigit, Abdurrahim; Oner, Ebru Toksoy; Eroglu, Mehmet S.In this study, a novel paclitaxel (PTX) loaded and a crosslinked solid phospholipid nanoparticles (SLN-PTX) with negative surface charge was prepared by UV polymerization for drug delivery. Capping of positive charge of zwitterionic lecithin with negative charge of sodium 2-acrylamido-2-methyl-1-propanesulfonate (AMPS-Na) through cation exchange interaction produced a lecithin-AMPS (L-AMPS) complex. The amphiphilic and negative charged lipid complex was emulsified in the presence of emulsifier, paclitaxel, initiator, and methacrylated poly epsilon-caprolacton-diol (PCL-MAC) as a spacer. The colloidal system was subjected to UV-irradiation to obtain crosslinked nanoparticles. Completion of the UV-polymerization was monitored with differential scanning calorimetry (DSC), which indicated the disappearance of exothermic peaks of vinyl groups. The nanoparticle system, having an average size of 200 nm, exhibited high drug encapsulation (96%) with negatively charged surface (zeta potential had an average of -70 mV). PTX release profiles of the crosslinked and uncrosslinked SLN-PTXs were studied and their pharmacological properties were compared. The crosslinked nanoparticles exhibited more controlled release behavior with longer release time compared to the uncrosslinked ones. In vitro cytotoxicity test was conducted on MCF-7 human breast adenocarcinoma cell line, which indicated that the crosslinked SLN-PTXs have a potential therapeutic effect for breast cancer treatments. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44105.Publication Metadata only Development and characterization of vancomycin-loaded levan-based microparticular system for drug delivery(TAYLOR & FRANCIS LTD, 2017) SEZER, ALİ DEMİR; Sezer, Ali Demir; Sarilmiser, Hande Kazak; Rayaman, Erkan; Cevikbas, Adile; Oner, Ebru Toksoy; Akbuga, JulideEncapsulation of vancomycin (VANCO) into biodegradable levan microparticles was achieved using a simple preparation technique. Microparticles were prepared by using levan polysaccharide produced by a halophilic bacterium Halomonas smyrnensis AAD6(T). To optimize efficiency of encapsulation process by precipitation method, three parameters were studied: drug and polymer concentrations and preparation rotating speed. The particles were characterized in vitro. The size of levan microparticles was changed between 0.404 mu m and 1.276 mu m. The surface charge was detected between +4.1 mV and +6.5 mV. The highest drug encapsulation capacity of the system was 74.7% and was depending on the polymer concentration. In dissolution studies, initial burst effect around 10-20% from all the formulations was observed and then the release was slowed down and continued at a constant level. In vitro antibiotic release from the microparticles was controlled with the drug carrier system and release fit to Higuchi kinetic model. All the released samples collected at different time intervals during dissolution studies have exhibited intrinsic bactericidal activity against Bacillus subtilis ATCC 6633. WST-1 cell proliferation and viability studies showed that VANCO-loaded levan microparticles at concentrations between 100 mu g/mL and 1000 mu g/mL were nontoxic to L929 cells. As conclusion, levan microparticulate system could be a potential carrier of antibiotic drugs such as VANCO.Publication Metadata only Synthesis and characterization of levan hydrogels and their use for resveratrol release(SAGE PUBLICATIONS LTD, 2021) TOKSOY ÖNER, EBRU; Selvi, Sinem Selvin; Haskoylu, Merve Erginer; Genc, Seval; Toksoy Oner, EbruConsidering the need for systematic studies on levan based hydrogels to widen their use in drug delivery systems and biomedical applications, this study is mainly focused on the synthesis and comprehensive characterization as well as drug release properties of hydrogels based on Halomonas levan (HL) and its chemical derivatives. For this, hydrolyzed and phosphonated HL derivatives were chemically synthesized and then cross-linked with 1,4-Butanediol diglycidyl ether (BDDE) and the obtained hydrogels were characterized in terms of their swelling, adhesivity, and rheological properties. Both native and phosphonated HL hydrogels retained their rigid gel like structure with increasing shear stress levels and tack test analysis showed superior adhesive properties of the phosphonated HL hydrogels. Moreover, hydrogels were loaded with resveratrol and entrapment and release studies as well as cell culture studies with human keratinocytes were performed. Biocompatible and adhesive features of the hydrogels confirmed their suitability for tissue engineering and drug delivery applications.Publication Metadata only Sugar Based Biopolymers in Nanomedicine; New Emerging Era for Cancer Imaging and Therapy(BENTHAM SCIENCE PUBL LTD, 2017) TOKSOY ÖNER, EBRU; Eroglu, Mehmet S.; Oner, Ebru Toksoy; Mutlu, Esra Cansever; Bostan, Muge SennarogluSince last decade, sugar based biopolymers are recognized in nanomedicine as promising materials for cancer imaging and therapy. Their durable, biocompatible and adhesive properties enable the fine tuning of their molecular weights (MW) and their miscellaneous nature makes the molecules acquire various conformations. These in turn provide effective endocytosis by cancer cell membranes that have already been programmed for internalization of different kinds of sugars. Therefore, biocompatible sugar based nanoparticles (SBNPs) are suitable for both cell-selective delivery of drugs and imaging through the human body. Recently, well known sugar-based markers have displayed superior performance to overcome tumor metastasis. Thereby, targeting strategies for cancer cells have been broadened to sugar-based markers as noticed in various clinic phases. In these studies, biopolymers such as chitosan, hyaluronic acid, mannan, dextran, levan, pectin, cyclodextrin, chondroitin sulphate, alginates, amylose and heparin are chemically functionalized and structurally designed as new biocompatible nanoparticles (NPs). The future cancer treatment strategies will mainly comprise of these multifunctional sugar based nanoparticles which combine the therapeutic agents with imaging technologies with the aim of rapid monitoring response to therapies. While each individual imaging and treatment step requires a long time period in effective treatment of diseases, these multifunctional sugar based nanoparticles will have the advantage of rapid detection, right drug efficiency evaluation and immediate interfere opportunity to some important diseases, especially rapidly progressing cancers. In this article, we evaluated synthesis, characterization and applications of main sugar based biopolymers and discussed their great promise in nano-formulations for cancer imaging and therapy. However much should be done and optimized prior to clinical applications of these nano-formulations for an efficient drug treatment without overall toxicity for getting most effective clinical results.Publication Metadata only Encapsulated melatonin in polycaprolactone (PCL) microparticles as a promising graft material(ELSEVIER SCIENCE BV, 2019) ÖZBEYLİ, DİLEK; Gurler, Esra Bihter; Ergul, Necdet Mekki; Ozbek, Burak; Ekren, Nazmi; Oktar, Faik Nuzhet; Haskoylu, Merve Erginer; Oner, Ebru Toksoy; Eroglu, Mehmet Sayip; Ozbeyli, Dilek; Korkut, Veysel; Temiz, Ahmet Furkan; Kocanali, Nil; Gungordu, Rosa Juvan; Kilickan, Duhan Berkan; Gunduz, OguzhanElectrospraying assures many advantages with taking less time and costing less relatively to the other conventional particle production methods. In this research, we investigated the encapsulation of melatonin (MEL) hormone in polycaprolactone (PCL) microparticles by using electrospraying method. Morphology analysis of the produced particles completed with Scanning Electron Microscopy (SEM). SEM images demonstrated that microparticles of 3 wt% PCL solution has the most suitable particle diameter size (2.3 +/- 0.64 mu m) for melatonin encapsulation. According to the characterization of the particles, electrospraying parameters like optimal collecting distance, the flow rate of the solution and voltage of the system detected as 8 cm, 0.5 ml/h, and 10 kV respectively. For determining the chemical bonds of scaffold Fourier-Transform Infrared Spectroscopy (FTIR) were used and FTIR results showed that melatonin successfully loaded into PCL micro-particles. Drug release kinetics of the melatonin loaded particles indicated that melatonin released with a burst at the beginning and release behavior became sustainable over a period of 8 h with the encapsulation efficiency of about 73%. In addition, both in-vitro and in-vivo studies of the graft materials also completed. Primary human osteoblasts (HOB) cells and female Sprague Dawley rats were used in in-vitro and in-vivo studies. Test results demonstrate cell population, and bone volume of the rats grafted with composites has remarkably increased, this caused remodelling in bone structure. Overall, these findings indicate that encapsulation of melatonin in the PCL particles with electrospray method is optimum for new synthetic graft material.