Yazar "Yurtsever, Merve Capkin" seçeneğine göre listele

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    A new application of avocado oil to enrich the biological activities of polycaprolactone membranes for tissue engineering
    (Wiley, 2024) Yurtsever, Merve Capkin; Aydogan, Selin; Iyigundogdu, Zeynep; Comertpay, Alican; Demir, Didem; Ceylan, Seda
    The metabolites synthesized by plants to protect themselves serves as natural antimicrobial agents used in biomaterials. In this study, avocado oil (AO), was incorporated as a plant source and natural antimicrobial agent into polycaprolactone (PCL) membranes. The effects of varying AO ratios (25, 50, and 100 wt%.-PCL@25AO, PCL@50AO, PCL@100AO) on PCL membrane morphology, chemical structure, wettability, antimicrobial activity, and cell viabilities were investigated. It was demonstrated that the AO acts as a pore-forming agent in solvent-casted membranes. Young's modulus of the membranes varied between 602.68 and 31.92 MPa and more flexible membranes were obtained with increasing AO content. Inhibition zones of AO were recorded between 7.86 and 13.97 mm against clinically relevant microbial strains including bacteria, yeast, and fungi. Antimicrobial activity of AO was retained in PCL membranes at all ratios. Resazurin assay indicated that PCL@25AO membranes were cytocompatible with mouse fibroblast cells (L929 cell line) on day 6 showing 72.4% cell viability with respect to neat PCL membranes. Viability results were supported by scanning electron microscopy images and DAPI staining. The overall results of this study highlight the potential of PCL@25AO membranes as a biomaterial with antimicrobial properties, cytocompatibility, and mechanical strength suitable for various biomedical applications. image
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    Öğe
    A new application of avocado oil to enrich the biological activities of polycaprolactone membranes for tissue engineering
    (Wiley, 2024) Yurtsever, Merve Capkin; Aydogan, Selin; Iyigundogdu, Zeynep; Comertpay, Alican; Demir, Didem; Ceylan, Seda
    The metabolites synthesized by plants to protect themselves serves as natural antimicrobial agents used in biomaterials. In this study, avocado oil (AO), was incorporated as a plant source and natural antimicrobial agent into polycaprolactone (PCL) membranes. The effects of varying AO ratios (25, 50, and 100 wt%.-PCL@25AO, PCL@50AO, PCL@100AO) on PCL membrane morphology, chemical structure, wettability, antimicrobial activity, and cell viabilities were investigated. It was demonstrated that the AO acts as a pore-forming agent in solvent-casted membranes. Young's modulus of the membranes varied between 602.68 and 31.92 MPa and more flexible membranes were obtained with increasing AO content. Inhibition zones of AO were recorded between 7.86 and 13.97 mm against clinically relevant microbial strains including bacteria, yeast, and fungi. Antimicrobial activity of AO was retained in PCL membranes at all ratios. Resazurin assay indicated that PCL@25AO membranes were cytocompatible with mouse fibroblast cells (L929 cell line) on day 6 showing 72.4% cell viability with respect to neat PCL membranes. Viability results were supported by scanning electron microscopy images and DAPI staining. The overall results of this study highlight the potential of PCL@25AO membranes as a biomaterial with antimicrobial properties, cytocompatibility, and mechanical strength suitable for various biomedical applications. image
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    Forecasting Gastric Cancer Diagnosis, Prognosis, and Drug Repurposing with Novel Gene Expression Signatures
    (Mary Ann Liebert, Inc, 2022) Demirtas, Talip Yasir; Rahman, Md Rezanur; Yurtsever, Merve Capkin; Gov, Esra
    Gastric cancer (GC) is a prevalent disease worldwide with high mortality and poor treatment success. Early diagnosis of GC and forecasting of its prognosis with the use of biomarkers are directly relevant to achieve both personalized/precision medicine and innovation in cancer therapeutics. Gene expression signatures offer one of the promising avenues of research in this regard, as well as guiding drug repurposing analyses in cancers. Using publicly accessible gene expression datasets from the Gene Expression Omnibus and The Cancer Genome Atlas (TCGA), we report here original findings on co-expressed gene modules that are differentially expressed between 133 GC samples and 46 normal tissues, and thus hold potential for novel diagnostic candidates for GC. Furthermore, we found two co-expressed gene modules were significantly associated with poor survival outcomes revealed by survival analysis of the RNA-Seq TCGA datasets. We identified STAT6 (signal transducer and activator of transcription 6) as a key regulator of the identified gene modules. Finally, potential therapeutic drugs that may target and reverse the expression of the identified altered gene modules examined for drug repurposing analyses and the unraveled compounds were further investigated in the literature by the text mining method. Accordingly, we found several repurposed drug candidates, including Trichostatin A, Vorinostat, Parthenolide, Panobinostat, Brefeldin A, Belinostat, and Danusertib. Through text mining analysis and literature search validation, Belinostat and Danusertib were suggested as possible novel drug candidates for GC treatment. These findings collectively inform multiple aspects of GC medical management, including its precision diagnosis, forecasting of possible outcomes, and drug repurposing for innovation in GC medicines in the future.
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    Melissa officinalis essential oil loaded polycaprolactone membranes: evaluation of antimicrobial activities and cytocompatibility for tissue engineering applications
    (Iop Publishing Ltd, 2023) Iyigundogdu, Zeynep; Petek, Betul Sena; Yurtsever, Merve Capkin; Ceylan, Seda
    Antimicrobial biomaterials play important role in tissue engineering applications to protect damaged tissue from infections. The aim of this study is producing antimicrobial polycaprolactone (PCL) membranes by using a plant based antimicrobial agent. Therefore,Melissa officinalisessential oil (MEO) was investigated against ten types of microorganisms and remarkable antimicrobial activity was demonstrated. PCL:MEO membranes were prepared by solvent casting method by mixing MEO into PCL in various ratios (PCL:0M, PCL:0.25M, PCL:0.5M, and PCL:1M w/w). Water contact angle measurements showed that hydrophilicity of the membranes increased with increasing concentrations of MEO from 103.44 degrees to 83.36 degrees for PCL:0M and PCL:1M, respectively. It was determined that there was an inverse relationship between the MEO concentration and the mechanical properties. Notable antioxidant activity of PCL/MEO membranes was exhibited by the inhibition percent of 2,2-diphenyl-1-picrylhydrazyl (DPPH) which was increased from 24.74% to 44.79% for PCL:0M and PCL:1M, respectively. The antimicrobial activity of MEO was also highly maintained in PCL membranes. For PCL/MEO membranes, at least 99.9% of microorganisms were inhibited. Cytocompatibility of the membranes were investigated by resazurin assay, scanning electron microscopy analysis and 4',6-diamidino-2-phenylindole (DAPI) staining. PCL:0.25M and PCL:0.5M membranes supported the viability of L929 cells more than 87% when compared to PCL:0M membranes on day 6. However, the viability of L929 cells on PCL:1M membranes was about 43% indicating significant decrease on cellular activity. In conclusion, PCL:0.25M and PCL:0.5M membranes with their high antimicrobial activity, acceptable mechanical properties and cytocompatible properties, they can be considered as an alternative biomaterial for tissue engineering applications.
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    Scaffolds from medical grade chitosan: A good choice for 3D cultivation of mesenchymal stem cells
    (Tubitak Scientific & Technological Research Council Turkey, 2022) Yurtsever, Merve Capkin; Akdere, Ozge Ekin; Gumusderelioglu, Menemse
    Chitosan has high biocompatibility, supports proliferation of many cells, and can be a good carrier for various growth factors. However, low attachment ratio and spheroid formation of several stem cell types on plain chitosan scaffolds/films is still a problem. In this study, it was aimed to obtain 3D scaffolds using medical grade chitosan (MC) with a high deacetylation degree (DD >= 92.6%) to overcome the spheroid formation of rat adipose tissue derived mesenchymal stem cells (rAdMSCs) on control chitosan (C, DD = 75%-85%) scaffolds. Genipin was used as a biological chemical crosslinker, and glycerol phosphate salt was used both as a pH adjusting agent and physical crosslinker. MTT and SEM analyses and live/dead staining indicated the increase in the attachment, cell viability, and proliferation of rAdMSCs on MC scaffolds with or without crosslinking when compared to the cells in spheroid formation on control scaffolds. Moreover, filamentous actin protein organization of rAdMSCs was found to be triggered on the crosslinked MC scaffolds. In conclusion, plain medical grade chitosan scaffolds with or without crosslinking prevented spheroid formation, supported the attachment, proliferation, and organization of rAdMSCs indicating that medical grade type of chitosan scaffolds with high DD can be a very good candidate as 3D carriers in stem cell cultivation.
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    TiO2, CeO2, and TiO2-CeO2 nanoparticles incorporated 2.5D chitosan hydrogels: Gelation behavior and cytocompatibility
    (Elsevier, 2023) Yurtsever, Merve Capkin; Guldag, Gozde
    In this study, gelation behavior and cytocompatibility of 2.5D chitosan hydrogels were investigated in the presence of TiO2, CeO2 and TiO2-CeO2 composite nanoparticles. Chemical co-precipitation method was used for nanoparticle synthesis and they were heat treated at 600 degrees C and 700 degrees C. Gelation of the chitosan solutions was carried out at 37 degrees C in the presence of glycerol phosphate and genipin as crosslinkers. The gelation time of chitosan was decreased by all of the nanoparticles whereas its elastic modulus was increased by nanoparticles addition. Chitosan solutions containing CeO2 or TiO2-CeO2 nanoparticles showed faster gel formation compared to chitosan solutions containing only TiO2 nanoparticles. CeO2@700 degrees C nanoparticles decreased the gelation time by 46% and increased elastic modulus by 14%. Average pore diameter of the hydrogel decreased from 127 & PLUSMN; 62 & mu;m to 77 & PLUSMN; 33 & mu;m, water uptake decreased 21% and thermal stability increased in the presence of CeO2@700 degrees C nanoparticles compared to chitosan hydrogel. Cell viability results indicated that chitosan hydrogels with or without nanoparticles created 2.5D environment supporting cellular proliferation approximately 1.5 times more than TCPS due to their high porous surfaces. Immunofluorescence images were also supported cell viability results. Therefore, CeO2 or TiO2-CeO2 composite nanoparticles incorporated 2.5D chitosan hydrogels may be alternative tissue engineering materials with their fast gelation, ease of use, low cost, light transparency, and cytocompatibility.