DSpace Arşivi :: by Yazar "Yagci, Yusuf" değerine göre listeleniyor

Yazar "Yagci, Yusuf" seçeneğine göre listele

Listeleniyor 1 - 20 / 41

Antibacterial Acrylamide Hydrogels Containing Silver Nanoparticles by Simultaneous Photoinduced Free Radical Polymerization and Electron Transfer Processes
(Wiley-V C H Verlag Gmbh, 2009) Uygun, Mustafa; Kahveci, Muhammet U.; Odaci, Dilek; Timur, Suna; Yagci, Yusuf
Ag-nanoparticle-containing hydrogels were successfully prepared by in situ reduction of silver nitrate in the presence of citrate molecules as stabilizing agent during photoinduced copolymerization of AAm and BAAm. Swelling-de swelling behavior and thermal properties of the synthesized hydrogels were investigated. The interior morphology of the gels exhibit continuity, which is a common feature for hydrogel networks. Antimicrobial activities of the hydrogels were also investigated against pathogenic E. coli O157:H7, S. aureus, and non-pathogenic E. coli K-12, which are model microorganisms for testing bactericidal properties. The hydrogels containing well-dispersed Ag NPs showed significant antibacterial activity.
Antibacterial Acrylamide Hydrogels Containing Silver Nanoparticles by Simultaneous Photoinduced Free Radical Polymerization and Electron Transfer Processes
(Wiley-V C H Verlag Gmbh, 2009) Uygun, Mustafa; Kahveci, Muhammet U.; Odaci, Dilek; Timur, Suna; Yagci, Yusuf
Ag-nanoparticle-containing hydrogels were successfully prepared by in situ reduction of silver nitrate in the presence of citrate molecules as stabilizing agent during photoinduced copolymerization of AAm and BAAm. Swelling-de swelling behavior and thermal properties of the synthesized hydrogels were investigated. The interior morphology of the gels exhibit continuity, which is a common feature for hydrogel networks. Antimicrobial activities of the hydrogels were also investigated against pathogenic E. coli O157:H7, S. aureus, and non-pathogenic E. coli K-12, which are model microorganisms for testing bactericidal properties. The hydrogels containing well-dispersed Ag NPs showed significant antibacterial activity.
Bioconjugation and Applications of Amino Functional Fluorescence Polymers
(Wiley-V C H Verlag Gmbh, 2017) Geyik, Caner; Guler, Emine; Gumus, Zinar Pinar; Barlas, Firat Baris; Akbulut, Huseyin; Demirkol, Dilek Odaci; Timur, Suna; Yagci, Yusuf
Synthesis and novel applications of biofunctional polymers for diagnosis and therapy are promising area involving various research domains. Herein, three fluorescent polymers, poly(p-phenylene-co-thiophene), poly(p-phenylene), and polythiophene with amino groups (PPT-NH2, PPP-NH2, and PT-NH2, respectively) are synthesized and investigated for cancer cell targeted imaging, drug delivery, and radiotherapy. Polymers are conjugated to anti-HER2 antibody for targeted imaging studies in nontoxic concentrations. Three cell lines (A549, Vero, and HeLa) with different expression levels of HER2 are used. In a model of HER2 expressing cell line (A549), radiotherapy experiments are carried out and results show that all three polymers increase the efficacy of radiotherapy. This effect is even more increased when conjugated to anti-HER2. In the second part of this work, one of the selected polymers (PT-NH2) is conjugated with a drug model; methotrexate via pH responsive hydrazone linkage and a drug carrier property of PT-NH2 is demonstrated on neuroblastoma (SH-SY5Y) cell model. Our results indicate that, PPT-NH2, PPP-NH2, and PT-NH2 have a great potential as biomaterials for various bioapplications in cancer research.
Biomimetic-electrochemical-sensory-platform for biomolecule free cocaine testing
(Elsevier Science Bv, 2018) Sengel, Tulay Yilmaz; Guler, Emine; Arslan, Mustafa; Gumus, Z. Pinar; Sanli, Serdar; Aldemir, Ebru; Akbulut, Huseyin; Demirkol, Dilek Odaci; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
A biomimetic cocaine sensor was fabricated by using poly(p-phenylene) (PPP) with cyclodextrin (CD) units in the backbone and poly(ethylene glycol) (PEG) side chains (PPP-CD-g-PEG). The sensory platform was constructed by one step surface modification of glassy carbon electrode with PPP-CD-g-PEG by drop coating. The electrochemical measurements are based on the formation of CD-cocaine inclusion complex on the surface resulting in a significant decrease in electron transfer capacity of the selected redox probe. The changes in the surface features due to cocaine binding were explored via electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry and electrochemical impedance spectrometry. The sensor exhibited linearity in the range of 25-200 nM cocaine, LOD was calculated as 28.62 nM (n = 5) according to 3Sb/m formula. Finally, the sensory platform was successfully applied for the cocaine analysis in synthetic urine samples and correlated with the chromatographic method.
"Biomimetic-electrochemical-sensory-platform" for biomolecule free cocaine testing
(Elsevier Science Bv, 2018) Sengel, Tulay Yilmaz; Guler, Emine; Arslan, Mustafa; Gumus, Z. Pinar; Sanli, Serdar; Aldemir, Ebru; Yagci, Yusuf
A biomimetic cocaine sensor was fabricated by using poly(p-phenylene) (PPP) with cyclodextrin (CD) units in the backbone and poly(ethylene glycol) (PEG) side chains (PPP-CD-g-PEG). The sensory platform was constructed by one step surface modification of glassy carbon electrode with PPP-CD-g-PEG by drop coating. The electrochemical measurements are based on the formation of CD-cocaine inclusion complex on the surface resulting in a significant decrease in electron transfer capacity of the selected redox probe. The changes in the surface features due to cocaine binding were explored via electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry and electrochemical impedance spectrometry. The sensor exhibited linearity in the range of 25-200 nM cocaine, LOD was calculated as 28.62 nM (n = 5) according to 3Sb/m formula. Finally, the sensory platform was successfully applied for the cocaine analysis in synthetic urine samples and correlated with the chromatographic method.
Catechol-Attached Polypeptide with Functional Groups as Electrochemical Sensing Platform for Synthetic Cannabinoids
(Amer Chemical Soc, 2020) Durmus, Ceren; Aydindogan, Eda; Gumus, Zinar Pinar; Endo, Takeshi; Yamada, Shuhei; Coskunol, Hakan; Yagci, Yusuf
Herein, we first constructed a functional surface using a catechol-attached polypeptide (CtP) for the detection of JWH-018 (N-4-hydroxypentyl metabolite). K2 antibody was then incorporated to the polymer via covalent cross-linker. Step-by-step modifications on the glassy carbon electrode surface were characterized by electrochemical measurements such as differential pulse voltammetry, cyclic voltammetry, impedance spectroscopy, and X-ray photoelectron spectroscopy. Linearity and the limit of detection for JWH-018 (N-4-hydroxypentyl metabolite) were determined as 10-500 ng/mL with an equation of y = 0.0018x + 0.136 (R-2 = 0.993) and 5.892 ng/mL, respectively. the selectivity of the biosensor was evaluated with different interfering molecules (methamphetamine, codeine, and cocaine). Finally, the biosensor was successfully used in the determination of JWH-018 (N-4-hydroxypentyl metabolite) in spiked synthetic urine samples, and a high-performance liquid chromatography (HPLC) system was used as a reference method to confirm the sample application. the results show that this biosensor platform can be applied to detect other JWH series of synthetic cannabinoids with high sensitivity and accuracy.
Complex Structured Fluorescent Polythiophene Graft Copolymer as a Versatile Tool for Imaging, Targeted Delivery of Paclitaxel, and Radiotherapy
(Amer Chemical Soc, 2016) Guler, Emine; Akbulut, Huseyin; Geyik, Caner; Yilmaz, Tulay; Gumus, Z. Pinar; Barlas, F. Baris; Ahan, Recep Erdem; Demirkol, Dilek Odaci; Yamada, Shuhei; Endo, Takeshi; Timur, Suna; Yagci, Yusuf
Advances in polymer chemistry resulted in substantial interest to utilize their diverse intrinsic advantages for biomedical research. Especially, studies on drug delivery for tumors have increased to a great extent. In this study, a novel fluorescent graft copolymer has been modified by a drug and targeting moiety and the resulting structure has been characterized by alterations in fluorescent intensity. The polythiophene based hybrid graft copolymer was synthesized by successive organic reactions and combination of in situ N-carboxy anhydride (NCA) ring opening and Suzuki coupling polymerization processes. Initially, targeted delivery of the graft copolymer was investigated by introducing a tumor specific ligand, anti-HER2/neu antibody, on the structure. The functionalized polymer was able to differentially indicate HER2-expressing A549 human lung carcinoma cells, whereas no signal was obtained for Vero, monkey kidney epithelial cells, and HeLa, human cervix adenocarcinoma cells. After integrating paclitaxel into the structure, cell viability, cell cycle progression, and radiosensitivity studies demonstrate HER2/neu targeting polymers inhibit cell proliferation. Importantly, the graft copolymer used had no cytotoxic effects to cells, as evidenced by cell viability and cell cycle analysis. This work clearly confirms that a specially designed and fabricated graft copolymer with a highly complex structure is a promising theranostic agent capable of targeting tumor cells for diagnostic and therapeutic purposes.
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.
Double fluorescence assay via a beta-cyclodextrin containing conjugated polymer as a biomimetic material for cocaine sensing
(Royal Soc Chemistry, 2017) Arslan, Mustafa; Sengel, Tulay Yilmaz; Guler, Emine; Gumus, Z. Pinar; Aldemir, Ebru; Akbulut, Huseyin; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
A double fluorescence mu-well assay that exploits a novel conjugated polymer containing cyclodextrin (CD) as the key component is reported. For the construction of the cocaine bioassay, poly(p-phenylene) with CD units in the main-chain and poly(ethylene glycol) side chains (PPP-CD-g-PEG) was first prepared by Suzuki coupling polymerization and coated on each well as a biomimetic material. Although the poly-phenylene backbone is responsible for the fluorescence properties without an additional fluorophore, PEG and CD provide water solubility and selective complexation with cocaine, respectively. A cocaine antibody was used as a secondary recognition compound after labelling with quantum dots (QDs). Most notably, we show that the two-color fluorescence nature of the assay facilitates double measurement from the same sample and the described strategy can be adapted to various sensing systems.
Electrochemical deposition of polypeptides: bio-based covering materials for surface design
(Royal Soc Chemistry, 2014) Akbulut, Huseyin; Yavuz, Murat; Guler, Emine; Demirkol, Dilek Odaci; Endo, Takeshi; Yamada, Shuhei; Timur, Suna; Yagci, Yusuf
A simple and efficient approach for the electrochemical deposition of polypeptides as bio-based covering materials for surface design is described. The method involves N-carboxyanhydride (NCA) ring-opening polymerization from its precursor to form a thiophene-functionalized polypeptide macromonomer (T-Pala), followed by electropolymerization. The obtained conducting polymer, namely polythiophene-g- polyalanine (PT-Pala), was characterized and utilized as a matrix for biomolecule attachment. The biosensing applicability of PT-Pala was also investigated by using glucose oxidase (GOx) as a model enzyme to detect glucose. The designed biosensor showed a very good linearity for 0.01-1.0 mM glucose. Finally, the antimicrobial activities of newly synthesized T-Pala and PT-Pala were also evaluated by using the disc diffusion method.
Fluorescence Sensing of Glucose Using Glucose Oxidase Modified by PVA-Pyrene Prepared via "Click" Chemistry
(Amer Chemical Soc, 2009) Odaci, Dilek; Gacal, Bahadir N.; Gacal, Burcin; Timur, Suna; Yagci, Yusuf
Poly(vinyl alcohol)-pyrene-glucose oxidase (PVA-Py-GOx), a water-soluble polymer possessing both fluorescent and oxidant sites in the structure, is synthesized by "click" chemistry and modification processes and characterized. The morphology of PVA-Py-GOx was characterized with atomic force microscopy (AFM), and a heterogeneous morphology due to the incorporation of GOx was observed. The capability of PVA-Py-GOx to act as a bioprobe for fluorescence sensing of glucose is examined. The postulated fluorescence mechanism for glucose analysis is based on the consumption of glucose by dissolved oxygen and GOx present in the structure. Thus, the fluorescence intensity of pyrene groups of the probe increases by the elimination of fluorescence quenching by oxygen. Glucose concentration was analyzed quantitatively from 0.25 to 3.0 mM by the fluorescence measurement. The effect of pH and amount of PVA-Py-GOx was also studied. The proposed system was applied to analyze glucose in real samples and compared with those obtained from commercial kits.
Fluorescence Sensing of Glucose Using Glucose Oxidase Modified by PVA-Pyrene Prepared via "Click" Chemistry
(Amer Chemical Soc, 2009) Odaci, Dilek; Gacal, Bahadir N.; Gacal, Burcin; Timur, Suna; Yagci, Yusuf
Poly(vinyl alcohol)-pyrene-glucose oxidase (PVA-Py-GOx), a water-soluble polymer possessing both fluorescent and oxidant sites in the structure, is synthesized by "click" chemistry and modification processes and characterized. The morphology of PVA-Py-GOx was characterized with atomic force microscopy (AFM), and a heterogeneous morphology due to the incorporation of GOx was observed. The capability of PVA-Py-GOx to act as a bioprobe for fluorescence sensing of glucose is examined. The postulated fluorescence mechanism for glucose analysis is based on the consumption of glucose by dissolved oxygen and GOx present in the structure. Thus, the fluorescence intensity of pyrene groups of the probe increases by the elimination of fluorescence quenching by oxygen. Glucose concentration was analyzed quantitatively from 0.25 to 3.0 mM by the fluorescence measurement. The effect of pH and amount of PVA-Py-GOx was also studied. The proposed system was applied to analyze glucose in real samples and compared with those obtained from commercial kits.
From Invisible Structures of SWCNTs toward Fluorescent and Targeting Architectures for Cell Imaging
(Amer Chemical Soc, 2013) Ag, Didem; Seleci, Muharrem; Bongartz, Rebecca; Can, Mustafa; Yurteri, Seda; Cianga, Ioan; Stahl, Frank; Timur, Suna; Scheper, Thomas; Yagci, Yusuf
Single-walled carbon nanotubes (SWNTs) are unique nanostructures used as cargo systems for variety of diagnostic and therapeutic agents. For taking advantage of these structures in biological processes, they should be visible. Therefore, fluorescence labeling of SWCNTs with various probes is a significant issue. Herein, we demonstrate a simple approach for cell specific imaging and diagnosis by combining SWCNTs with a copolymer poly(para-epsilon-caprolactone) (PCL) side chains (PPP-g-PSt-PCL). In this approach PPP-g-PSt-PCL is noncovalently attached on carboxyl functional SWCNTs. The obtained fluorescent probe is bound to folic acid (FA) for targeted imaging of folate receptor (FR) positive HeLa cells. In vitro studies demonstrate that this conjugate can specifically bind to HeLa cells and indicate great potential for targeting and imaging studies.
A Functional Platform for the Detection of JWH-073 as a Model for Synthetic Cannabinoids
(Wiley-V C H Verlag Gmbh, 2018) Sengel, Tulay Yilmaz; Celik, Emine Guler; Aydogan, Cansu; Gumus, Zinar Pinar; Ilktac, Raif; Aydindogan, Eda; Ciftci, Mustafa; Aldemir, Ebru; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
During the last decade, progress has been made in the on-site detection of abused drug use. Herein, we present an electrochemical biosensor for the detection of one of the synthetic cannabinoids (SCs), JWH-073, using poly (methyl methacrylate) (PMMA) hyperbranched copolymer (HBC) as a base coating and antibody molecules to bind the JWH-073 to the surface. Modification of the surface is proved with various techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry. The limit of detection and linearity (in logarithmic scale) for JWH-073 were found to be 31.87 ng/mL and 25-500 ng/mL, respectively. The selectivity of the proposed biosensor was also tested in the presence of interfering molecules and the response was much higher for JWH-073 in all measurements. In the final part of the study, synthetic urine was tested with the device and the relative standard deviation value was calculated to be less than 5.0%. The confirmation of data from the resulting bio-platform was performed via LC-QTOF/MS. This work is the first of its kind, a novel, rapid, cost-effective sensing platform for the detection of the SC.
Functional poly(p-phenylene)s as targeting and drug carrier materials
(Taylor & Francis As, 2016) Guler, Bahar; Akbulut, Huseyin; Geyik, Caner; Barlas, F. Baris; Demirkol, Dilek Odaci; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
Polymers have a substantial attention in drug delivery systems owing to the diverse intrinsic advantages. It is important to carry the drug to the target site and release to exert its effects. Herein, poly(p-phenylene)s with amino and poly(ethylene glycol) substituents (PPP-NH2-g-PEG) were used as a carrier for doxorubicin (DOX), an anticancer drug, and haloperidol, a sigma receptor targeting ligand. Both human cervix adenocarcinoma cell line (HeLa) and human keratinocyte cell line (HaCaT) having different Sigma receptor 1 (SigmaR1) expression levels were compared. HeLa was found to express twofold SigmaR1 compared to HaCaT cells. Cell imaging studies showed that, DOX cell uptake was higher in HeLa cells when targeted with haloperidol. [GRAPHICS] .
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.
Highly conjugated isoindigo and quinoxaline dyes as sunlight photosensitizers for onium salt-photoinitiated cationic polymerization of epoxy resins
(Wiley, 2022) Ercan, Bahar T.; Gultekin, Sirin S.; Yesil, Tamer; Dincalp, Haluk; Koyuncu, Sermet; Yagci, Yusuf; Zafer, Ceylan
In this study, photoinitiated cationic polymerization of epoxy resins by photoinduced electron transfer reactions using four new chromophoric dyes, namely (3E)-1,1 '-bis(2-ethylhexyl)-6,6 '-dipyren-1-yl-3,3 '-biindole-2,2 '(1H,1 ' H)-dione (ISOIV), (3 ' E)-1,1 '''-diethyl-1 ',1 ''-bis(2-ethylhexyl)-1H,1 ''' H-5,6 ':3 ',3 '':6 '',5 '''-quaterindole-2 ',2 ''(1 ' H,1 '' H)-dione (ISOV), (3E)-6,6 '-bis(9-ethyl-9H-carbazole-3-yl)-1-[(2R)-2-ethylhexyl]-1 '-[(2S)-2-ethylhexyl]-3,3 '-biindole-2,2 '(1H,1 ' H)-dione (ISOVIII) and 3,3 '-(6-bromokinoksalin-2,3-diyl)bis(9-ethyl-9H-carbazole) (TPDC6), and diphenyliodonium hexafluorophosphate (Ph2I+PF6-; DPI) under sunlight is reported. Upon irradiation, photoexcited dye forms an exciplex with DPI. Electron transfer reactions within the exciplex result in the formation of ionic species capable of initiating ring-opening polymerization of an epoxy resin. It is shown that among the investigated dyes, ISOVIII and TPDC6 exhibited higher initiation efficiency in accordance with their stronger electron-donating nature due to the presence of carbazole groups. (c) 2021 Society of Industrial Chemistry.
An immunoelectrochemical platform for the biosensing of 'Cocaine use'
(Elsevier Science Sa, 2017) Sengel, Tulay Yilmaz; Guler, Emine; Gumus, Z. Pinar; Aldemir, Ebru; Coskunol, Hakan; Akbulut, Huseyin; Colak, Demet Goen; Cianga, Ioan; Yamada, Shuhei; Timur, Suna; Endo, Takeshi; Yagci, Yusuf
In the present work, we demonstrate a novel surface design by combination of benzoylecgonine (BE) antibody and poly-L-phenylalanine bearing electroactive macromonomer (EDOT-BTDA-PPhe). This system served as an electro-immunosensor platform for the analysis of cocaine use by detecting both BE and cocaine. To construct the immunosensor, a glassy carbon electrode was covered with EDOT-BTDA-PPhe. Subsequently, BE antibody was immobilized on the polypeptide chains. The surface modifications were confirmed by electrochemical techniques. The immunosensor was used for the electrochemical detection of BE and cocaine as evidence of drug addiction. For both analytes, linearity was obtained between 0.5-25 mu M. Finally, the proposed system was successfully employed for the analysis of synthetic biological fluids. (C) 2017 Elsevier B.V. All rights reserved.
In situ synthesis of biomolecule encapsulated gold-cross-linked poly(ethylene glycol) nanocomposite as biosensing platform: A model study
(Elsevier Science Sa, 2010) Odaci, Dilek; Kahveci, Muhammet U.; Sahkulubey, Elif L.; Ozdemir, Caglar; Uyar, Tamer; Timur, Suna; Yagci, Yusuf
In situ synthesis of poly(ethylene glycol) (PEG) hydrogels containing gold nanoparticles (AuNPs) and glucose oxidase (GOx) enzyme by photo-induced electron transfer process was reported here and applied in electrochemical glucose biosensing as the model system. Newly designed bionanocomposite matrix by simple one-step fabrication offered a good contact between the active site of the enzyme and AuNPs inside the network that caused the promotion in the electron transfer properties that was evidenced by cyclic voltammetry as well as higher amperometric biosensing responses in comparing with response signals obtained from the matrix without AuNPs. As well as some parameters important in the optimization studies such as optimum pH, enzyme loading and AuNP amount, the analytical characteristics of the biosensor (AuNP/GOx) were examined by the monitoring of chronoamperometric response due to the oxygen consumption through the enzymatic reaction at -0.7 V under optimized conditions at sodium acetate buffer (50 mM, pH 4.0) and the linear graph was obtained in the range of 0.1-1.0 mM glucose. The detection limit (LOD) of the biosensor was calculated as 0.06 mM by using the signal to noise ratio of 3. Moreover, the presence of AuNPs was visualized by TEM. Finally, the biosensor was applied for glucose analysis for some beverages and obtained data were compared with HPLC as the reference method to test the possible matrix effect due to the nature of the samples. (C) 2010 Elsevier B.V. All rights reserved.
Mobile Phone Sensing of Cocaine in a Lateral Flow Assay Combined with a Biomimetic Material
(Amer Chemical Soc, 2017) Guler, Emine; Sengel, Tulay Yilmaz; Gumus, Z. Pinar; Arslan, Mustafa; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
Lateral flow assays (LFAs) are an ideal choice for drug abuse testing favored by their practicability, portability, and rapidity. LFA based on site rapid screening devices provide positive/negative judgment in a short response time. The conventionally applied competitive assay format used for small molecule analysis such as abused drugs restricts the quantitation ability of LFA strips. We report herein, for the first time, a new strategy using the noncompetitive assay format via a biomimetic material, namely, poly(p-phenylene) beta-cyclodextrin poly(ethylene glycol) (PPP-CD-g-PEG) combined with gold nanoparticle (AuNP) conjugates as the labeling agent to recognize the target cocaine molecule in the test zone. The intensities of the visualized red color in the test line indicate that the cocaine concentrations were analyzed via a smartphone application. Significantly, a combination of this platform with a smartphone application provides quantitative data on the cocaine amount, making it a very inventive and attractive approach especially for on-site applications at critical points such as traffic stops and the workplace.

Yazar "Yagci, Yusuf" seçeneğine göre listele

Sayfa Başına Sonuç

Sıralama seçenekleri