DSpace Arşivi :: by Yazar "Demir, Bilal" değerine göre listeleniyor

Yazar "Demir, Bilal" seçeneğine göre listele

Listeleniyor 1 - 20 / 33

Amine intercalated clay surfaces for microbial cell immobilization and biosensing applications
(Royal Soc Chemistry, 2013) Demir, Bilal; Seleci, Muharrem; Ag, Didem; Cevik, Serdar; Yalcinkaya, Esra Evrim; Demirkol, Dilek O.; Anik, Ulku; Timur, Suna
Trimethylamine (TM) intercalated montmorillonite (Mont) clay was prepared and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential and thermal gravimetric measurements. Gluconobacter oxydans cells were immobilized on the micro-structured matrix and used in microbial sensor applications. Sensor responses were based on the respiratory activity of the cells and the consumption of oxygen was monitored at 20.7 V (vs. Ag/AgCl and platinum electrodes) by using glucose as a substrate. Stabilization of the bacteria was performed on the Mont using glutaraldehyde. Optimization of the TM-Mont/G. oxydans sensor and examination of the electrochemical mechanism were carried out in a batch system. Measurements concerning analytical characteristics, operational stability, repeatability and substrate specificity depending on the carbon source in the culture were investigated in a flow injection analysis (FIA) system. Linear ranges were found between 0.15 and 5.0 mM for the batch mode and 0.1 and 5.0 mM for the FIA system, respectively. Finally, real samples were analyzed and were compared with the results of a spectrophotometric method as reference.
Amine intercalated clay surfaces for microbial cell immobilization and biosensing applications
(Royal Soc Chemistry, 2013) Demir, Bilal; Seleci, Muharrem; Ag, Didem; Cevik, Serdar; Yalcinkaya, Esra Evrim; Demirkol, Dilek O.; Anik, Ulku; Timur, Suna
Trimethylamine (TM) intercalated montmorillonite (Mont) clay was prepared and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential and thermal gravimetric measurements. Gluconobacter oxydans cells were immobilized on the micro-structured matrix and used in microbial sensor applications. Sensor responses were based on the respiratory activity of the cells and the consumption of oxygen was monitored at 20.7 V (vs. Ag/AgCl and platinum electrodes) by using glucose as a substrate. Stabilization of the bacteria was performed on the Mont using glutaraldehyde. Optimization of the TM-Mont/G. oxydans sensor and examination of the electrochemical mechanism were carried out in a batch system. Measurements concerning analytical characteristics, operational stability, repeatability and substrate specificity depending on the carbon source in the culture were investigated in a flow injection analysis (FIA) system. Linear ranges were found between 0.15 and 5.0 mM for the batch mode and 0.1 and 5.0 mM for the FIA system, respectively. Finally, real samples were analyzed and were compared with the results of a spectrophotometric method as reference.
Amino acid intercalated montmorillonite: electrochemical biosensing applications
(Royal Soc Chemistry, 2014) Demir, Filiz; Demir, Bilal; Yalcinkaya, Esra E.; Cevik, Serdar; Demirkol, Dilek Odaci; Anik, Ulku; Timur, Suna
The present work is the first that includes the use of glycine (Gly), lysine (Lys) and glutamic acid (Glu) modified clay mineral matrices in the biosensors. For this purpose, initially, Gly, Lys and Glu were intercalated with montmorillonite (Mt), thus, various modified Mts were obtained. These modified materials were then characterized via X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential and thermal gravimetric analysis (TGA/DTG) and scanning electron microscopy (SEM). In order to investigate the applicability of amino acid modified clay minerals in biosensor areas, glucose oxidase (GOx) was selected as the model enzyme and a GOx based biosensor was prepared. After immobilizing the enzyme with amino acid modified Mt onto a glassy carbon electrode, working conditions like pH and modifier type were optimized. Among the modified Mts, Gly-Mt was the optimum clay mineral type and pH 4.0 was the optimum pH value. Then analytical characteristics were examined under optimum experimental conditions. The linear range of optimum sensor design was 0.1-1.0 mM within the kinetic parameters of an immobilized enzyme K-m(app) m = 0.7 mM, I-max = 107.8 nA. Finally, the developed biosensor was applied to real samples where the results were compared with a spectrophotometric reference method.
An aptamer folding-based sensory platform decorated with nanoparticles for simple cocaine testing
(Wiley, 2017) Guler, Emine; Bozokalfa, Guliz; Demir, Bilal; Gumus, Zinar Pinar; Guler, Bahar; Aldemir, Ebru; Timur, Suna; Coskunol, Hakan
The consumption of illicit drugs such as cannabis, cocaine, and amphetamines is still a major health and social problem, creating an abuse in adults especially. Novel techniques which estimate the drug of abuse are needed for the detection of newly revealed psychoactive drugs. Herein, we have constructed a combinatorial platform by using quantum dots (QDs) and gold nanoparticles (AuNPs) as well as a functional aptamer which selectively recognizes cocaine and its metabolite benzoylecgonine (BE). We have called it an aptamer folding-based sensory device (AFSD). For the fabrication of AFSD, QDs were initially immobilized onto the poly-L-lysine coated -well surfaces. Then, the AuNP-aptamer conjugates were bound to the QDs. The addition of cocaine or BE caused a change in the aptamer structure which induced the close interaction of AuNPs with the QDs. Hence, quenching of the fluorescence of QDs was observed depending on the analyte amount. The linearity of cocaine and BE was 1.0-10 nM and 1.0-25M, respectively. Moreover, the limits of detection for cocaine and BE were calculated as 0.138 nM and 1.66M. The selectivity was tested by using different interfering substances (methamphetamine, bovine serum albumin, codeine, and 3-acetamidophenol). To investigate the use of AFSD in artificial urine matrix, cocaine/BE spiked samples were applied. Also, confirmatory analyses by using high performance liquid chromatography were performed. It is shown that AFSD has a good potential for testing the cocaine abuse and can be easily adapted for detection of various addictive drugs by changing the aptamer according to desired analytes. Copyright (c) 2016 John Wiley & Sons, Ltd.
Bio-active nanoemulsions enriched with gold nanoparticle, marigold extracts and lipoic acid: In vitro investigations
(Elsevier Science Bv, 2014) Guler, Emine; Barlas, F. Baris; Yavuz, Murat; Demir, Bilal; Gumus, Z. Pinar; Baspinar, Yucel; Coskunol, Hakan; Timur, Suna
A novel and efficient approach for the preparation of enriched herbal formulations was described and their potential applications including wound healing and antioxidant activity (cell based and cell free) were investigated via in vitro cell culture studies. Nigella sativa oil was enriched with Calendula officinalis extract and lipoic acid capped gold nanoparticles (AuNP-LA) using nanoemulsion systems. The combination of these bio-active compounds was used to design oil in water (O/W) and water in oil (W/O) emulsions. The resulted emulsions were characterized by particle size measurements. The phenolic content of each nanoemulsion was examined by using both colorimetric assay and chromatographic analyses. Two different methods containing cell free chemical assay (1-diphenyl-2-picrylhydrazyl method) and cell based antioxidant activity test were used to evaluate the antioxidant capacities. In order to investigate the bio-activities of the herbal formulations, in vitro cell culture experiments, including cytotoxicity, scratch assay, antioxidant activity and cell proliferation were carried out using Vero cell line as a model cell line. Furthermore, to monitor localization of the nanoemulsions after application of the cell culture, the cell images were monitored via fluorescence microscope after FITC labeling. All data confirmed that the enriched N. sativa formulations exhibited better antioxidant and wound healing activity than N. sativa emulsion without any enrichment. In conclusion, the incorporation of AuNP-LA and C officinalis extract into the N. sativa emulsions significantly increased the bio-activities. The present work may support further studies about using the other bio-active agents for the enrichment of herbal preparations to strengthen their activities. (C) 2014 Elsevier B.V. All rights reserved.
BIOFUNCTIONALIZED NANOMATERIALS FOR TARGETING CANCER CELLS
(Elsevier Science Bv, 2017) Guler, Emine; Demir, Bilal; Guler, Bahar; Demirkol, Dilek Odaci; Timur, Suna; Ficai, A; Grumezescu, AM
Carbon dots and curcumin-loaded CD44-Targeted liposomes for imaging and tracking cancer chemotherapy: A multi-purpose tool for theranostics
(Elsevier, 2021) Demir, Bilal; Moulahoum, Hichem; Ghorbanizamani, Faezeh; Barlas, F. Baris; Yesiltepe, Ozan; Gumus, Z. Pinar; Timur, Suna
Growing needs in biomedical applications have driven the development of multifunctional nanoparticles towards theranostically-engineered multimodal platforms. Many strategies for point-effective cellular uptake of theranostics have been described. in this report, multifunctional nanostructures were designed and synthesized as a novel theranostic platform. Liposomes were loaded with curcumin as a therapeutic agent and carbon dots (CDs) as a contrast molecule. Anti-CD44 antibodies were bioconjugated on the liposomal surface to obtain an active targeting nanocarrier. After synthesis, the relative characterization of the vesicles was performed using DLS and TEM techniques. in vitro analysis was conducted to investigate the multimodal properties of the theranostic via testing its toxicity, cell uptake, bioimaging, and chemo/radiotherapy applications on two different cell lines. 3D holographic microscopy was employed to track the treatment effects during experimentation. Results indicated that these particles are efficient tools for clinical applications due to their fluorescent characteristic and increased bioperformance.
Comparative cell adhesion properties of cysteine extended peptide architectures
(Royal Soc Chemistry, 2016) Soylemez, Saniye; Demir, Bilal; Eyrilmez, Gizem Oyman; Kesici, Seckin; Saylam, Aytul; Demirkol, Dilek Odaci; Ozcubukcu, Salih; Timur, Suna; Toppare, Levent
This study presents the comparative cell attachment investigation of TAT and well-known RGD peptide modified surfaces. Initially, cysteine containing arginine-glycine-aspartic acid (RGD) and TAT peptides, a class of cell penetration peptides, were synthesized. Gold film coated indium tin oxide (gold/ITO) surfaces were coated with RGD and TAT peptides and used for cell culture applications. Thiol groups on the peptides provide post-modification of the surface. The efficient bonding of the peptides with the modified surface brings proper attachment of the cells. The peptide modified surfaces were tested for adhesion of several cell lines such as monkey kidney epithelial cell (Vero), human cervical carcinoma cell (HeLa), human glioblastoma cell (U87-MG) and human immortalized skin keratinocyte cell (HaCaT) lines. These cells were cultured on RGD and TAT modified gold/ITO surfaces. Cell imaging studies were performed on these surfaces using fluorescence microscopy technique. Scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and contact angle measurements were carried out for the surface characterization. The results indicate that the RGD and TAT modified surfaces exhibited better cell adhesion. Therefore, besides RGD as a well-known adhesion peptide, TAT functionalized substrates were found to be efficient bio-sensing candidates for further studies.
Controlled release of anticancer drug Paclitaxel using nano-structured amphiphilic star-hyperbranched block copolymers
(Royal Soc Chemistry, 2015) Geyik, Caner; Ciftci, Mustafa; Demir, Bilal; Guler, Bahar; Ozkaya, A. Burak; Gumus, Z. Pinar; Barlas, F. Baris; Demirkol, Dilek Odaci; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
In the present study, two amphiphilic star-hyperbranched copolymers based on poly(methyl methacrylate)-b-poly(2-hydroxyethyl methacrylate) (PMMA-b-PHEMA), with different hydrophilic PHEMA segment contents (PMMA-b-PHEMA-1, and PMMA-b-PHEMA-2), were synthesized, and their drug loading and release profiles were examined using Paclitaxel (PTX) as a model drug. The drug loading capacities and encapsulation efficiencies were found to be similar in both polymers. The encapsulation efficiencies were found to be prominent at 98% and 98.5% for PMMA-b-PHEMA-1 and PMMA-b-PHEMA-2, respectively. On the other hand, the drug release behaviors varied in favor of the block copolymer comprising shorter PHEMA chains (PMMA-b-PHEMA-1). Additionally, to assess the biological effects of PTX-loaded polymers, human non-small cell lung carcinoma (A549) cells were used. Cell viability and cell cycle analysis showed that both polymers were non-toxic to cells. The cytotoxic effect of PTX-loaded PMMA-b-PHEMA-1 on A 549 cells was greater (66.49% cell viability at 5.0 ng mL(-1) PTX) than that of PMMA-b-PHEMA-2 (72.47% cell viability at 5.0 ng mL(-1) PTX), consistent with the drug release experiments.
An electrochemical cytosensor based on a PAMAM modified glassy carbon paste electrode
(Royal Soc Chemistry, 2015) Tepeli, Yudum; Demir, Bilal; Timur, Suna; Anik, Ulku
A novel electrochemical cytosensor was developed based on PAMAM and a folic acid (FA) modified glassy carbon paste electrode (GCPE) where HeLa cells were utilized as model cancer cells. For this purpose, gold nanoparticles (AuNp), cysteamin (Cys), glutaraldehyde (Glu), PAMAM and FA were immobilized onto the GCPE respectively. After the characterization of the GCPE/AuNp/Cys/Glu/PAMAM/FA cytosensor and optimization of the experimental parameters, analytical characteristics were examined. The linear range was found between 10(2) cells per mL and 10(6) cells per mL. The LOD value was calculated as 100 cells per mL with RSD value of 1.55% (for 5.0 x 10(4) HeLa cells per mL (n = 3)). The selectivity of the GCPE/AuNp/Cys/Glu/PAMAM/FA cytosensor was tested by using the folate negative cell line A549. The cytosensor's performance was also compared with similar previous studies. As a result, a selective, sensitive and practical system was developed.
Folic-Acid-Modified Conducting Polymer: Electrochemical Detection of the Cell Attachment
(Wiley-V C H Verlag Gmbh, 2016) Azak, Hacer; Barlas, Firat Baris; Yildiz, Huseyin Bekir; Gulec, Kadri; Demir, Bilal; Demirkol, Dilek Odaci; Timur, Suna
Here, postfunctionalization and bioapplication of a pi-conjugated polymer named 4-[4H-dithieno(3,2-b:2',3'-d)pyrrol-4-yl]aniline (DTP-aryl-NH2) are reported, which is successfully synthesized via electropolymerization onto the glassy carbon electrode. Folic acid (FA) is used to modify the amino functional polymer via N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide chemistry for the further steps. The selective adhesion of folate receptor positive cells on the surface is followed by the electrochemical methods. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize stepwise modification of the electroactive surface. After optimization studies such as scan rate during the polymer deposition, FA amount for the efficient surface targeting, incubation time with the cells etc., analytical characterization is carried out. The surface morphologies at each step are imaged by using fluorescence microscopy.
Functional Surfaces Constructed with Hyperbranched Copolymers as Optical Imaging and Electrochemical Cell Sensing Platforms
(Wiley-V C H Verlag Gmbh, 2018) Balta, Sebila; Aydogan, Cansu; Demir, Bilal; Geyik, Caner; Ciftci, Mustafa; Guler, Emine; Demirkol, Dilek Odaci; Timur, Suna; Yagci, Yusuf
In the present study, hyperbranched copolymers (HBCs), namely poly(methyl methacrylate) (PMMA)-co-poly(2-hydroxyethylmethacrylate) and PMMA-co-poly(2-dimethylamino ethyl methacrylate), are photochemically synthesized by self-condensing vinyl polymerization of methyl methacrylate with the corresponding inimer using Type II photoinitiators. HBCs with different functional group and branching densities are used as surface coating materials in cellular adhesion and the respective electrochemical-based studies. After the main surface characterization of the synthesized three HBCs with contact angle measurements and atomic force microscopy, HaCaT keratinocytes and human neuroglioblastoma (U-87MG) cell lines to the surfaces are conducted. The adherence of cells is proven by both fluorescence cell imaging and electrochemical methods such as cyclic voltammetry and differential pulse voltammetry. The described strategy involving hyperbranched polymers offers great potential for fabricating various new surfaces in particular on-chip-sensing applications.
Görüntüleme kılavuzlu ve tedaviye yönelik nanoparçacıkların sentezi ve in vitro uygulamaları
(Ege Üniversitesi, Fen Bilimleri Enstitüsü, 2017) Demir, Bilal; Timur, Suna
Biyomedikal uygulamalardaki büyüyen ihtiyaca yönelik olarak multifonksionel nanopartiküllerin diğer bir tanımla tek bir partikülde hem tedavi hem de diyagnoz özelliği taşıyan teranostiklerin gelişimi hızlanmıştır. Bu bağlamda teranostiklerin etkin hücresel alımını sağlamak için çeşitli kompozisyon ve biyokonjugasyonlar ile görüntüleme kılavuzlu terapi amacıyla birçok stratejiye başvurulmuştur. Bu tez projesinde, multifonksiyonel nanopartiküller, yenilikçi teranostikler olarak tasarlandı ve sentezlendi. Genel tasarım olarak, teranostiklere yönelik sentez stratejileri dünyada en çok mortalitenin ikinci görüldüğü hastalığa ilişkin olarak kanserli hücre hatlarına göre planlanmıştır. Tez çalışmasında kullanılan ana nanopartiküller, yüzey modifikasyonu, polimer kaplama, enkapsülasyon ve folik asit ya da antikor ile biyokonjugasyonu ile yapılan ileri işlevselliğe ve hedefleme kabiliyetine sahip altın nanopartiküller (AuNP), karbon noktalar (CD) ve lipozomlar ve niozomları gibi veziküler sistemlerdir. Bunun için, fonksiyonel polimer kaplı AuNP'ler, FA bağlanmış niozomlar ve anti-CD44 bağlı lipozomlar ve bununla beraber moleküler baskılanmış polimer kaplı CD'ler çalışılmıştır. Tüm nanopartiküllerin sentezi sonrasında, ilgili karakterizasyon ve takibinde in vitro hücre temelli çalışmalar teranostiklerin toksisite, hücre alımı, biyogörüntüleme ve kemo/radyo- ya da fotodinamik terapiuygulamaları ile multimodal özellikleri incelenmiştir. Tez kapsamında elde edilen tim sonuçlar, bu fütüristik partiküllerin aydınlatılmış karakteristikleri ve artırılmış biyokimyasal performansları sayesinde klinik amaçlar doğrultusunda etkin araçlar olabileceğini işaret etmektedir.
Görüntüleme kılavuzlu ve tedaviye yönelik nanoparçacıkların sentezi ve in vitro uygulamaları
(Ege Üniversitesi, 2017) Demir, Bilal; Timur, Suna
Biyomedikal uygulamalardaki büyüyen ihtiyaca yönelik olarak multifonksionel nanopartiküllerin diğer bir tanımla tek bir partikülde hem tedavi hem de diyagnoz özelliği taşıyan teranostiklerin gelişimi hızlanmıştır. Bu bağlamda teranostiklerin etkin hücresel alımını sağlamak için çeşitli kompozisyon ve biyokonjugasyonlar ile görüntüleme kılavuzlu terapi amacıyla birçok stratejiye başvurulmuştur. Bu tez projesinde, multifonksiyonel nanopartiküller, yenilikçi teranostikler olarak tasarlandı ve sentezlendi. Genel tasarım olarak, teranostiklere yönelik sentez stratejileri dünyada en çok mortalitenin ikinci görüldüğü hastalığa ilişkin olarak kanserli hücre hatlarına göre planlanmıştır. Tez çalışmasında kullanılan ana nanopartiküller, yüzey modifikasyonu, polimer kaplama, enkapsülasyon ve antikor ile biyokonjugasyonu ile yapılan ileri işlevselliğe ve hedefleme kabiliyetine sahip altın nanopartiküller (AuNP), karbon noktalar (CD) ve lipozomlar ve niozomları gibi veziküler sistemlerdir. Bunun için, fonksiyonel polimer kaplı AuNP'ler ve anti-CD44 bağlı lipozomlar ve bununla beraber moleküler baskılanmış polimer kaplı CD'ler çalışılmıştır. Tüm nanopartiküllerin sentezi sonrasında, ilgili karakterizasyon ve takibinde in vitro hücre temelli çalışmalar teranostiklerin toksisite, hücre alımı, biyogörüntüleme ve kemo/radyoterapi uygulamaları ile multimodal özellikleri incelenmiştir. Tez kapsamında elde edilen tim sonuçlar, bu fütüristik partiküllerin aydınlatılmış karakteristikleri ve artırılmış biyokimyasal performansları sayesinde klinik amaçlar doğrultusunda etkin araçlar olabileceğini işaret etmektedir.;Teranostikler, multifonksiyonel nanopartiküller, multimodal terapi,biyogörüntüleme,biyokonjugasyon.;Theranostics, multifunctional nanoparticles, multimodal therapy, bioimaging, bioconjugation.
Hücre çoğalması üzerine etkili olabilecek seçilmiş bitki ekstraktlarının eldesi ve in vitro testleri
(Ege Üniversitesi, 2014) Demir, Bilal; Timur, Suna; İnce, İskender
Tıbbi ve farmasötik özelliğe sahip herbal ekstrelerin sulu ortamlarda çözünebilirlikleri zayıftır ve canlı hücreler tarafından absorpsioyunu düşüktür. Bunların lipozomal enkapsülasyonları diğer bir adıyla ✹fitozomlar' bu problemin üstesinden gelmek için çözüm sunabilmektedir. Bunun yanı sıra birçok araştırma altın nanopartikül (AuNP) gibi metalik nanopartiküllerin canlı hücreler üzerinde antioksidan, yara iyileştirme gibi biyolojik aktiviteleri olduğunu göstermiştir. Burada, yeni bir lipozomal formülasyon hem Calendula officinalis ektresi hem de AuNP lerin birlikte enkapsülasyonu ile yapılmıştır. Geleneksel ince film hidrasyon ve ekstrüzyon yöntemiyle veziküllerin hazırlanmasından sonra, üretilen AuNP-fitozomlar, sırasıyla dynamic light scattering boyut ölçümleri, zeta potansiyel ve atomik kuvvet mikroskopisi ile karakterize edilmiştir. Bu veziküller 100 nm altında olup, Calendula ekstresindeki model majör bileşenler olan klorojenik asit ve kuersetinin enkapsülasyon etkinliği yüksektir. Ayrıca, AuNP-fitozomlar, boş lipozom, fitozomun yanında ve her bir enkapsüle edilen materyalin serbest formuna göre daha iyi antioksidan ve yara iyileştirme aktivitesini göstermiştir. Buna ek olarak, veziküllerin hücresel etkileşimleri floresans mikroskop altında Texas-Red işaretli lipidlerden hazırlanan nano-veziküller kullanılarak görüntülenmiştir. Son aşamada ise AuNP içermeyen örneklerin radyoprotektif aktivitesine bakıldıktan sonra AuNP-fitozomların patch (irritasyon testleri) testleri yapıldı.
Hücre çoğalması üzerine etkili olabilecek seçilmiş bitki ekstraktlarının eldesi ve in vitro testleri: bitkisel lipozomal preparatlara ilişkin çalışmalar
(Ege Üniversitesi, 2014) Demir, Bilal; Timur, Suna; İnce, Öğr. Gör. İskender
Tıbbi ve farmasötik özelliğe sahip herbal ekstrelerin sulu ortamlarda çözünebilirlikleri zayıftır ve canlı hücreler tarafından absorpsioyunu düşüktür. Bunların lipozomal enkapsülasyonları diğer bir adıyla 'fitozomlar' bu problemin üstesinden gelmek için çözüm sunabilmektedir. Bunun yanı sıra birçok araştırma altın nanopartikül (AuNP) gibi metalik nanopartiküllerin canlı hücreler üzerinde antioksidan, yara iyileştirme gibi biyolojik aktiviteleri olduğunu göstermiştir. Burada, yeni bir lipozomal formülasyon hem Calendula officinalis ektresi hem de AuNP lerin birlikte enkapsülasyonu ile yapılmıştır. Geleneksel ince film hidrasyon ve ekstrüzyon yöntemiyle veziküllerin hazırlanmasından sonra, üretilen AuNP-fitozomlar, sırasıyla dynamic light scattering boyut ölçümleri, zeta potansiyel ve atomik kuvvet mikroskopisi ile karakterize edilmiştir. Bu veziküller 100 nm altında olup, Calendula ekstresindeki model majör bileşenler olan klorojenik asit ve kuersetinin enkapsülasyon etkinliği yüksektir. Ayrıca, AuNP-fitozomlar, boş lipozom, fitozomun yanında ve her bir enkapsüle edilen materyalin serbest formuna göre daha iyi antioksidan ve yara iyileştirme aktivitesini göstermiştir. Buna ek olarak, veziküllerin hücresel etkileşimleri floresans mikroskop altında Texas-Red işaretli lipidlerden hazırlanan nano-veziküller kullanılarak görüntülenmiştir. Son aşamada ise AuNP içermeyen örneklerin radyoprotektif aktivitesine bakıldıktan sonra AuNP-fitozomların patch (irritasyon testleri) testleri yapıldı
Magnetic Nanofiber Layers as a Functional Surface for Biomolecule Immobilization and One-Use 'Sensing in-a-Drop' Applications
(Wiley-V C H Verlag Gmbh, 2018) Sanli, Serdar; Celik, Emine Guler; Demir, Bilal; Gumus, Z. Pinar; Ilktac, Raif; Aksuner, Nur; Demirkol, Dilek Odaci; Timur, Suna
Stabilization of biomolecules on matrices is critically important. Here we constructed composite nanofibers with magnetic features by electro-spinning of magnetic nanoparticles (MNP) in an appropriate polymer matrix on a collector surface for multiple uses. 'Poly(vinylalcohol)-polyethyleneimine/Fe3O4 magnetic nanoparticles' (PVA-PEI/MNP) composite nanofiber was used on the screen printed electrodes (SPE) to serve as a platform for the glucose oxidase (GOx) biofilm as the model biomolecule. To show the potential application of this material as a biosensor component, the resulted biofilm, called 'PVA-PEI/MNP/GOx', was fixed on SPE via a neodymium magnet for the electrochemical detection of glucose at -0.7 V where oxygen consumption due to enzymatic reaction was measured. The main advantage of the obtained magnetic biomembrane is that it allows analysis with a single drop. After step-by-step surface modifications, analytical characterization was performed using various techniques, such as voltammetry, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy and X-Ray photoelectron spectroscopy as well as microscopic techniques. The linear range of the PVA-PEI/MNP/GOx surface was found as 0.0125 to 0.5 mM with a limit of detection of 11.5 mu M for glucose as analyte. The application of PVA-PEI/MNP/GOx for glucose detection in synthetic samples was carried out. Data proved the potential use of the 'PVA-PEI/MNP' surface as a biomolecule immobilization platform for disposable biosensor applications.
Molybdenum oxide/platinum modified glassy carbon electrode: A novel electrocatalytic platform for the monitoring of electrochemical reduction of oxygen and its biosensing applications
(Elsevier Science Sa, 2013) Cakar, Irem; Ozdokur, K. Volkan; Demir, Bilal; Yavuz, Elvin; Demirkol, Dilek Odaci; Kocak, Suleyman; Timur, Suna; Ertas, Fatma Nil
The reduction of oxygen to water is one of the most important reactions in electrochemistry with regards to the wide range of applications in electrocatalysis, metal corrosion, and fuel cell and mostly in biosensor studies. Present study describes the use of a glassy carbon electrode modified with platinum and molybdenum oxide (Pt-MoOx) in strongly acidic solutions for electrocatalytic reduction of oxygen dissolved in buffer solution for the first time. The dispersion of Pt nanoparticles on MoOx provides larger surface area and better electrocatalytic activity for oxygen reduction and the best response toward dissolved oxygen was obtained with a mole ratio of 1: 90 Pt:Mo in deposition solution. The modified surface was then used as a biosensing platform for the monitoring of oxygen consumption due to the bio-catalytic action of glucose oxidase (GO(x)) as the model enzyme. After optimization of the operational conditions, analytical characterization and application of the glucose oxidase GO(x) biosensor to flow injection analysis mode have been successfully performed. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
Multimodal theranostic assemblies: double encapsulation of protoporphyrine-IX/Gd3+ in niosomes
(Royal Soc Chemistry, 2016) Barlas, F. Baris; Demir, Bilal; Guler, Emine; Senisik, A. Murat; Arican, H. Armagan; Unake, Perihan; Timur, Suna
Theranostic therapy is one of the most promising methods in cancer research, which simultaneously allows the treating and real-time monitoring of cancer. In the present study, a new method was developed to achieve advanced theranostic therapy by double encapsulation of gadolinium nanoparticles (GdNP) and protoporphyrin IX (PpIX) into niosomes. Hereby, niosomes are used for encapsulation of GdNP and PpIX, which will be called 'Gd-PpIX-NI'. Niosomes are chosen as the encapsulation material owing to their high biocompatibility, physical and chemical stability, and fair price. On the other hand, GdNP and PpIX are good sensitizers for radiotherapy (RT) and, particularly, porphyrin structures are one of the most studied agents for photodynamic therapy (PDT). In this study, a multimodal treatment was performed with the combination of PDT and RT by using human alveolar type-II (ATII)-like cells (A549) and human cervical cancer cell line (HeLa). Moreover, 'Gd-PpIX-NI' serves as a dual cell imaging probe that provides both fluorescence and magnetic resonance imaging. Characterization of the sizes and zeta potential of the niosomal vesicles was carried out by dynamic light scattering and atomic force microscopy. To determine the cell viability after treatment with Gd-PpIX-NI, followed by PDT and RT application, the MTT method was used. The results showed that Gd-PpIX-NI assembling was homogeneous and consistent in terms of particle size, which is less than 100 nm. This material has potential as a good candidate for both PDT and RT, as well as diagnosis.
Niosomes of Nerium oleander extracts: In vitro assessment of bioactive nanovesicular structures
(Elsevier Science Bv, 2017) Gunes, Aybike; Guler, Emine; Un, Rabia Nur; Demir, Bilal; Barlas, E. Baris; Yavuz, Murat; Coskunol, Hakan; Timur, Suna
Niosomes are known as non-ionic surfactant-based vesicles and have been used quite a lot for medical applications as a novel drug delivery system in recent years. Herein we describe, the preparation and characterization of niosomes containing oleander (Nerium oleander) (ONs) extract as the herbal compound. In this context, niosomal formulations of two different extracts obtained from oleander roots were prepared by a thin film hydration technique using Tween 60 (non-ionic surfactant) with a cholesterol mixture at 1:1 M ratio. These vesicular structures were characterised by various techniques such as atomic force microscopy, zeta potential and dynamic light scattering size measurements. ONs vesicles are less than 100 nm in size with a good physical stability more than 50 days. Initially, total phenolic and flavonoid contents and antioxidant activities of the extracts were investigated. The methanol extract of oleander roots (MOE) showed higher polyphenolic content and exhibits a better antioxidant activity in compared to the hydro-methanol (20% methanol) extract (MOWE). Total phenolic contents in the MOE and MOWE were calculated as 64.51 +/- 0.945 mu g/mg and 65.05 +/- 0.37 mu g/mg gallic acid equivalents, respectively. Encapsulation efficiencies of the vesicles were found as 16.2% for MON (contain MOE) and 13.24% for MWON (contain MOWE). The significant linear correlation Was confirmed between the antioxidant activity and total phenolic content of extracts as well as ONs. Cell based cytotoxic activities of methanol extract and MON formulations were also assessed via KIT assay using Hela and A549 cell lines. (C) 2016 Elsevier B.V. All rights reserved.

Yazar "Demir, Bilal" seçeneğine göre listele

Sayfa Başına Sonuç

Sıralama seçenekleri