Person: TOKSOY ÖNER, EBRU
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TOKSOY ÖNER
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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 Comprehensive characterization of chitosan/PEO/levan ternary blend films(ELSEVIER SCI LTD, 2014) TOKSOY ÖNER, EBRU; Bostan, Muge Sennaroglu; Mutlu, Esra Cansever; Kazak, Hande; Keskin, S. Sinan; Oner, Ebru Toksoy; Eroglu, Mehmet S.Ternary blend films of chitosan, PEO (300,000) and levan were prepared by solution casting method and their phase behavior, miscibility, thermal and mechanical properties as well as their surface energy and morphology were characterized by different techniques. FT-IR analyses of blend films indicated intermolecular hydrogen bonding between blend components. Thermal and XRD analysis showed that chitosan and levan suppressed the crystallinity of PEO up to nearly 25% of PEO content in the blend, which resulted in more amorphous film structures at higher PEO/(chitosan + levan) ratios. At more than 30% of PEO concentration, contact angle (CA) measurements showed a surface enrichment of PEO whereas at lower PEO concentrations, chitosan and levan were enriched on the surfaces leading to more amorphous and homogenous surfaces. This result was further confirmed by atomic force microscopy (AFM) images. Cell proliferation and viability assay established the high biocompatibility of the blend films. (C) 2013 Elsevier Ltd. All rights reserved.Publication Metadata only Development and optimization of a novel PLGA-Levan based drug delivery system for curcumin, using a quality-by-design approach(ELSEVIER, 2019) TOKSOY ÖNER, EBRU; Bahadori, Fatemeh; Eskandari, Zahra; Ebrahimi, Nabiallah; Bostan, Muge Sennaroglu; Eroglu, Mehmet Sayip; Oner, Ebru ToksoyThis study aimed to develop a PLGA, Levan-based drug delivery system (DDS) of Curcumin using a quality-by-design (QbD) approach to reveal how formulation parameters affect the critical quality attributes (CQAs) of this DDS and to present an optimal design. First, a risk assessment was conducted to determine the impact of various process parameters on the CQAs of the DDS (i.e., average particle size, ZP, encapsulation efficiency and polydispersity index). Plackett-Burman design revealed that potential risk factors were Levan molecular weight, PLGA amount and acetone amount. Then, the optimization of the DDS was achieved through a Box-Behnken Design. The optimum formulation was prepared using low molecular weight Levan (134 kDa), 51.51 mg PLGA and 10 ml acetone. The model was validated and the optimized formulation was further characterized using different physic-chemical methods. The study resulted in the most stable NP with a spherical and uniform shape and physical stability tests indicated its stability for at least 60 days at room temperature. In conclusion, this study was an effort for developing a DDS which solubilizes Curcumin in clinically applicable concentrations.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 Gradient multifunctional biopolymer thin film assemblies synthesized by combinatorial MAPLE(ELSEVIER SCIENCE BV, 2019) TOKSOY ÖNER, EBRU; Mihailescu, Natalia; Haskoylu, Merve Erginer; Ristoscu, Carmen; Bostan, Muge Sennaroglu; Sopronyi, Mihai; Eroglu, Mehmet S.; Chifiriuc, Mariana Carmen; Mustaciosu, Cosmin Catalin; Axente, Emanuel; Oner, Ebru Toksoy; Mihailescu, Ion N.Combinatorial Matrix-Assisted Pulsed Laser Evaporation (C-MAPLE) was recently introduced to the fast generation of compositional libraries of two biopolymers in a single-step process, for tissue engineering and regenerative medicine applications. Synchronized laser irradiation of two distinct cryogenic targets, one consisting of Sulfated Halomonas Levan and the other of quaternized low molecular weight Chitosan was used to fabricate compositional gradient coatings for surface functionalization. Synthesized coatings preserved the base material composition as confirmed by Fourier Transform Infrared Spectroscopy. Morphological study by Scanning Electron Microscopy, Atomic Force Microscopy and profilometry correlated with water contact angles measurements demonstrated that the obtained thin coatings have improved surface properties with respect to pure material coatings. Fluorescence microscopy validated the compositional gradient, while in vitro assays evidenced characteristic responses of mouse fibroblasts (L929 cell line) by distinct deposition surface regions. The coagulation test pointed out good properties for Sulfated Halomonas Levan coatings as compared to the case of an increased amount of quaternized low molecular weight Chitosan biopolymer or the control. The antimicrobial effect of the coatings was demonstrated against Escherichia coli and Staphylococcus aureus strains, representative for both Gram negative and Gram positive bacterial species, respectively, mainly involved in implant and nosocomial infections. The assembled nanostructures possess variable anti-biofilm activity along the compositional gradient, with a stronger inhibitory effect on the initial adherence phase of both tested microbial strains, but also against mature Escherichia coli biofilms. It was shown that C-MAPLE can generate discrete areas of blended polymeric composition exhibiting improved surface properties for a broad range of biomedicine applications, e.g. the fabrication of thin bioactive and cell-instructive coatings with anti-adherence properties.