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Introduction: The aim of this study is to investigate the impact of obesity on patient compliance with elastic compression stockings and to reveal patient behavior-related and compression stockings-related factors for noncompliance. Patients and Methods: Between July and August 2022, a total of 246 patients with chronic venous insufficiency were included in the study. The patients were divided into two groups, obese and non-obese patients (88 vs. 158 patients), and questioned for proper use of compression stockings and the patient-reported reasons for the non-compliance. Results: The mean age was 49.0 ± 13.1, and the mean BMI was 28.6 ± 5.2. Only 51 patients (20.7%) out of 246 complied with stocking use. The mean number of days per week in which the compression stockings were properly used was 2.9 ± 1.7 in the study population. Patient compliance was higher in the non-obese group (12.5% vs. 25.3%, p= 0.017), and the number of days per week in which the compression stockings were worn properly was higher in the non-obese group (2.6 ± 1.3 vs. 3.1 ± 1.9, p= 0.032). Conclusion: The compliance of our patients with elastic compression stockings was found to be as low as 20.7%. Compliance was lower in the group of obese patients. Obesity and diabetes mellitus were the only factors associated with noncompliance in univariate logistic regression analysis. Further studies are needed in larger patient populations to increase the rate of patient compliance.

A novel lab-in-a-pencil graphite microfluidic sensing electrode (μFSE) was fabricated for real-time flow injection measurement of the antipsychotic drug clozapine (Clz). A simple, low-cost, and reusable μFSE was obtained by using 3D printing of a microfluidic chamber integrated with a flat pencil graphite without the need to utilize complex technologies. The μFSE has tubular geometry with 800 μm diameter, where the solution continuously flows in the holes of flat pencil graphite electrodes. Under optimized conditions, this device offers fast and effective Clz detection with good analytical features. A linear calibration curve in the range of 0.5 to 10 μM Clz was obtained with good sensitivity (0.01275 μA μM-1) and detection limit (24 nM). Finally, we demonstrate the applicability of our lab-fabricated microfluidic electrochemical device by monitoring Clz in serum samples at low concentrations.

Abnormal dopamine neurotransmission is associated with several neurological and psychiatric disorders such as Parkinson's disease, schizophrenia, attention deficiency and hyperactivity disorder, and addiction. Developing highly sensitive, selective, and fast dopamine monitoring methods is of high importance especially for the early diagnosis of these diseases. Herein, we report a new ultrasensitive electrochemical sensing platform for in situ monitoring of cell-secreted dopamine using Au-coated arrays of micropyramid structures integrated directly into a Petri dish. This approach enables the monitoring of dopamine released from cells in real-time without the need for relocating cultured cells. According to the electrochemical analyses, our dopamine sensing platform exhibits excellent analytical characteristics with a detection limit of 0.50 ± 0.08 nM, a wide linear range of 0.01-500 μM, and a sensitivity of 0.18 ± 0.01 μA/μM. The sensor also has remarkable selectivity toward DA in the presence of different potentially interfering small molecules. The developed electrochemical sensor has great potential for in vitro analysis of neuronal cells as well as early diagnosis of different neurological diseases related to abnormal levels of dopamine.

In this work, a new bio-electrochemical fuel cell was constructed and the effect of boron was investigated to obtain improved electrogenic activity of a green algae (Choricystis sp.). In a specially designed bio-electrochemical fuel cell, electrode combinations of indium tin oxide (ITO) and a carbon layer are used. Open circuit potential (OCP) measurements of algal cells placed bio-electrochemical fuel cells were performed with a cyclic on-off illumination of a LED light source. The results revealed that 60 μM is the efficient boron concentration for the algal growth and pigmentation. Higher doses of boron limited the algal growth. However, the algal growth reduced slightly at higher doses, pointing out a possible boron export mechanism in green algae. OCP analysis showed that hydrogen was electro-catalytically reduced at the cathode site and an 18 mV voltage was obtained from boron-deficient (0 μM) Choricystis sp. samples. A significant enhancement in voltage output up to 33 mV was achieved from 60 μM of boron-treated algal samples. The maximum power density was calculated from the boron-treated Choricystis sp. at pseudo-steady state as 42.2 mW m−2 at a current density of 154 mA m−2.

Here we present the simple and effective fabrication method of an array of gold microneedles (AuMNs) via the casting of conductive gold ink. To demonstrate the potential of MN arrays as electrochemical biosensors we functionalized AuMNs with an epoxy- and ferrocene-functional polymeric mediator and covalently immobilised urease. The performance of the MN array biosensor for urea detection was assessed in artificial interstitial fluid and epidermal/skin mimic, both spiked with urea. The analytical performance of MN biosensor shows that urea is detected in the range of 50–2500 µM, with a calculated limit of detection of 2.8 µM and sensitivity of 31 nA/mM. The results reveal that these MN-based biosensors may underpin the development of wearable real-time monitoring devices.

We present an electrochemical DNA detection strategy based on self-assembled ferrocene-cored poly(amidoamine) dendrimers for the detection of a gene relevant to breast cancer. The chemisorption of three ferrocene-cored poly(amidoamine) generations and hybridization of single-stranded DNA on a Au electrode were studied by cyclic voltammetry and differential pulse voltammetry. The biosensor demonstrated high sensitivity of 0.13 μA/(ng/ml) in the detection of the target DNA with a linear range of 1.3-20 nM and a detection limit of 0.38 nM. The DNA biosensor also has high selectivity for the target DNA, showing a clear signal difference from a noncomplementary sequence and a single-base-mismatch sequence, which was used as a model of BRAC1 gene mutation. The results shown are highly motivating for exploring DNA biosensing technology in the diagnosis of breast cancer caused by mutation of the BRAC1 gene. Graphical abstract.

The electrostatic layer-by-layer (LbL) assembled multilayer films were widely used in the biomedical technology such as drug delivery. In this work, loading capabilities and release behavio...

Aim: In this study, we aimed to evaluate the long-term results of combined treatment with rotational atherectomy (RA) and drug-coated balloon (DCB) in isolated total occlusion of the superficial femoral artery (SFA).Materials and Methods:The retrospective study was conducted between February 2016 and January 2018 and included a total of 23 limbs of 20 patients with isolated total occlusion of the SFA. Patient data on demographic and clinical characteristics were obtained from the hospital records. The stage of the disease was classified according to the Rutherford classification. The ankle–brachial index was measured pre- and postoperatively.Results:Of the patients, 19 (95%) were male and one (5%) was female. The mean patient age was 67.40±7.50 (49–77) years. The patient distribution according to the preoperative Rutherford classification was as follows: stage 5, four (17.40%) patients; stage 4, eight (34.80%) patients; stage 3, eleven (47.80%) patients. The rates of one- and two-year freedom from target lesion revascularization were 82.61% and 69.57%, respectively.Discussion and Conclusion:Our study results showed that combined treatment with RA and DCB was an effective method in SFA lesions with a high calcified plaque burden, providing high rates of primary patency and freedom from target lesion revascularization as well as low rates of complication.

Breast cancer is a group of diseases in which cells divide out of controlled, typically resulting in a mass. Erlotinib is targeted cancer drug which functions as an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. It is used mainly to treat of non-small cell lung cancer patients and has an action against pancreatic cancer. Vorinostat (aka suberanilohydroxamic acid) is an inhibitor of histone deacetylases (HDAC), which has an epigenetic modulation activity. It is used to treat cutaneous T cell lymphoma. In the present study, the erlotinib (ERL) and vorinostat (SAHA) loaded TiO2 nanoparticles (NPs) were used for the treatment of the breast cancer cells (MDA-MB-231 and MCF-7) and human cancerous amniotic cells (WISH). Cell count and viability were negatively affected in all treatments compared to normal cells and bare TiO2 NPs. Apoptosis results indicated a significant increase in the total apoptosis in all treatments compared with control cells. ERL- and SAHA-loaded TiO2 NPs treatments arrested breast cancer cells at G2/M phase, which indicate the cytotoxic effect of these treatment. Partner and localizer of BRCA2 (PALB2) gene expression was assessed using qPCR. The results indicate that PLAB2 was upregulated in ERL- and SAHA-loaded TiO2 NPs compared with control cells and can be used as nanocarrier for chemotherapy drugs. However, this conclusion necessitates further confirmative investigation.

Parkinson's disease (PD) is a progressive neurodegenerative disorder involving dopaminergic neurons from the substantia nigra. The loss of dopaminergic neurons results in decreased dopamine (DA) release in the striatum and thus impaired motor functions. DA is one of the key neurotransmitters monitored for the diagnosis and during the progression and treatment of PD. Therefore, sensitive and selective DA detection methods are of high clinical relevance. In this study, a new microfluidic device utilized for electrochemical DA detection is reported. The microfluidic sensing device operates in the range of 0.1-1000 nM DA requiring only ∼2.4 μL sample volume, which corresponds to detectable 240 amol of DA. Using this sensor, we were able to monitor the changes in DA levels in cerebrospinal fluid and plasma of a mouse model of PD and following the treatment of drug l-3,4-dihydroxyphenylalanine.

In this study, ferrocene (Fc) cored polyamidoamine (PAMAM) dendrimer generations were used as a mediator to produce photo-current by providing electrochemical communication between photosynthetic microorganisms and electrode. Photosynthetic microorganisms (PM) (algae and cyanobacteria mixture) were attached to the graphite electrode surface and photocurrent generation was demonstrated. A photocurrent density of 0.033 μA cm−2 was obtained by direct electron transfer of PM to the electrode without using any mediator. FcPAMAM structures with different redox potentials successfully interconnected the electrode and PM, resulting in a photocurrent density of 1.18 μA cm−2. Two different water-soluble mediators, p-benzoquinone and hexacyanoferrate (III), were used to accelerate photo-current through the reaction center and the photocurrent density was raised to 11.89 μA cm−2. Superoxide dismutase (SoD) and catalase (Cat) enzymes have been successfully used to remove reactive organic species (ROS) from the reaction center and further increase in photocurrent density was reached up to 20.04 μA cm−2.

In this work, we report novel amperometric urea biosensor based on immobilization of Urease enzyme onto self-assembled polyamidoamine grafted multiwalled carbon nanotube (MWCNT-PAMAM) dendrimers (from G1, first generation up to G5) on Au electrode. Bio-sensing electrode’s performance parameters such as optimum pH, temperature, and applied potential together with reproducibility were investigated. The electrode based on fifth generation of MWCNT-PAMAM and urease enzyme showed excellent performance in urea detection at an applied potential of 0.45 V with short response time of 3 s, wide linear range of 1–20 mM, detection limit of 0.4 mM, and sensitivity of 6.6 nA/mM. No significant response was detected in the presence of possible interferon molecules. Non-diluted human blood plasma has been used for real sample application where electrode showed excellent performance in urea detection.

In this study, chitosan-based novel scaffolds containing zeolite A were fabricated by freeze-drying technique. The nanocomposite scaffolds were prepared from chitosan and zeolite A nanocrystals with different amounts (0.5, 1.0, and 2.0%) in aqueous media. The zeolite A nanocrystals and nanocomposite scaffolds were characterized by using FTIR, X-ray powder diffraction, scanning electron microscope, and thermogravimetric analysis. The scaffolds were seeded with bone marrow-derived human mesenchymal stem cell line (UE7T-13), and cell attachment, viability, and cytotoxicity assays were performed. In vitro cytotoxicity of scaffolds toward human mesenchymal stem cell line was evaluated through the evaluation of cell viability and cell attachment assays.

In this work, fabrication of new electrochemical urea biosensor based on ferrocene-poly(amidoamine) (Fc-PAMAM) dendrimers incorporated with multi walled carbon nanotubes (MWCNTs) is reported. Bio-sensing electrode was characterized using cyclic voltammogram where optimization studies were performed for reusability, storage, interference behaviors together with optimum temperature and pH parameters. Electrode showed excellent performance in urea detection with wide linear range of 0.2–1.8 mM, detection limit of 0.05 mM, fast response of 3 s, and sensitivity of 1.085 μA/cm 2 /mM. Final assessment of electrochemical biosensor was real sample application which was performed in healthy human blood sample where excellent performance in selectivity and sensitivity of the bio-electrode was observed. Fabricated bio-sensing electrode has great potential in urea measurement applications.

Herein, an electrochemical urea sensing bio-electrode is reported that has been constructed by firstly electropolymerizing 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline monomer (SNS-Aniline) on Pencil Graphite Electrode (PGE), then modifying the polymer coated electrode surface with di-amino-Ferrocene (DAFc) as the mediator, and lastly Urease enzyme through glutaraldehyde crosslinking. The effect of pH, temperature, polymer thickness, and applied potential on the electrode current response was investigated besides performing storage and operational stability experiments with the interference studies. The resulting urea biosensor's amperometric response was linear in the range of 0.1-8.5mM with the sensitivity of 0.54μA/mM, detection limit of 12μM, and short response time of 2s. The designed bio-electrode was tested with real human blood and urine samples where it showed excellent analytical performance with insignificant interference.

In this study ferrocene, chitosan and ferrocene branched chitosan were synthesized to investigate carbon monoxide (CO) sensing properties and adsorption characteristics. The range of 0–2000 ppm CO concentrations was used as active gas, high purity nitrogen (N 2 ) and air were used as cleaning gases for desorption process. Sorption data were collected by quartz crystal microbalance (QCM) technique. A sensitive film production on QCM was achieved via drop-casting method. Langmuir model was applied to clarify CO adsorption and the desorption kinetics of ferrocene, chitosan and ferrocene branched chitosan with respect to reference N 2 . The results show that the ferrocene branched chitosan coated sensor has exhibited promising CO sensing property for CO sensor applications at room temperature.

In this study, an immunosensor was designed to utilize for the detection of prostate specific antigen (PSA) based on three different generations (G1, G2 and G3) of ferrocene (Fc) cored polyamidiamine dendrimers (Fc-PAMAM) gold (Au) electrode. The self-assembled monolayer principle (SAM) was used to fabricate the sensitive, selective and disposable immunosensor electrodes. In electrode fabrication cysteamine (Cys) was the first agent covalently linked on the Au electrode surface. Immobilized redox center (ferrocene) cored PAMAM dendrimers served as a layer for the further binding of biological components. The monoclonal antibody of PSA (anti-PSA) was covalently immobilized on dendrimers which were attached onto the modified Au surface (Au/Cys/Fc-PAMAMs/anti-PSA). PSA levels were quantitatively analyzed by using electrochemical differential pulse voltammetry (DPV) whose lowest detection limit was calculated as 0.001 ng mL −1 . The Au/Cys/FcPAMAM/anti-PSA immunosensor showed excellent performance for PSA at the pulse amplitude; 50 mV and the scan rate; 10 mV/s in a wide linear concentration range of 0.01 ng–100 ng mL −1 . Analytical performance and specificity assays were carried out using human serum and different proteins.

Nowadays, there is increasing number of electrochemical biosensors which utilize chitosan (Ch); as an enzyme immobilization matrix, and conductive nanomaterials; as electron carriers improving sensitivity of the biosensor. However, the challenge these sensors face is the lack of uniform dispersion of nanomaterials throughout the Ch film, which can negatively affect analytical performance of the biosensor. In this study, we report the development of an enzyme immobilization matrix that displays enhanced electrochemical performance thanks to a novel conductive thin film prepared via in situ electrocopolymerization of pyrrole (Py) and thiophene-grafted chitosan (Th-Ch). This is a simple thin film preparation method that can help overcome aforementioned challenges by providing a uniformly distributed conductive layer on the electrode. We are also for the first time reporting the synthesis and characterization of Th-Ch, where grafted Th plays an essential role as a linking group between Ch and Py. The resulting conductive Ch-based thin film was modified with glucose oxidase (GOx) which served as a model enzyme. In situ electrocopolymerization of Py with Th-Ch resulted in a highly conductive thin film enabling approximately 40% higher sensitivity when compared to a Py-Ch composite. This new type of composite thin film is promising in biosensor technology due to its biocompatibility, the chemically and physically modifiable structure, as well as its electrical conductivity.

This review (with 160 ref.) summarizes the progress that has been made in the methods for chemical or biochemical sensing of hypoxanthine and xanthine, which are produced as part of purine metabolism and are precursors of uric acid. An introduction discusses the importance of hypoxanthine and xanthine as analytes due to their significance in the clinical and food science, together with the conventional methods of analysis. A large section covers methods for the electrochemical hypoxanthine and xanthine sensing. It is divided into subsections according to the nanomaterials used including carbon nanomaterials, meal oxide nanoparticles, metal organic frameworks, conductive polymers, and bio-nanocomposites. A further large section covers optical methods for hypoxanthine and xanthine sensing, with subsections on nanomaterials including carbon nanomaterials, nanosheets, nanoclusters, nanoparticles, and their bio-nanocomposites. A concluding section summarizes the current status, addresses current challenges, and discusses future perspectives. Graphical abstractSchematic representation of the hypoxanthine and xanthine electrochemical and optical sensors incorporating various nanomaterials like graphene, carbon nanotubes (CNT), quantum dots (QD), nanoparticles and polymers, which are implemented in clinical and food analysis.

Amperometric biosensor was fabricated using nanocomposite film which is constructed by separate embedding of reduced expanded graphene oxide (REGO), REGO-gold, REGO-palladium, and REGO-platinum into poly(glycidyl methacrylate-co-vinylferrocene) (P(Vfc0.4-GMA)), and by covalent immobilization of xanthine oxidase (XOD) on the surface of nanocomposite-coated electrode. Using these tailored nanocomposites and surface binding of XOD, it has been systematically studied to obtain optimum and most ideal system for xanthine detection in real samples. The best performance in xanthine detection was REGO-platinum-based nanocomposite electrode which is able to detect xanthine with sensitivity of 21.98 μA/μM it has linear range of 1 to 40 μM, low detection limit of 0.003 μM, and excellent response time of 2 s. At the end, fabricated electrode was subjected to real sample testing by measuring xanthine concentration in chicken and meat. Biosensor was found to be very reliable and with minimum interference applicable in meat freshness control as well.

An amperometric cholesterol biosensor was fabricated by electropolymerization method of conducting polymers on pencil graphite electrode (PGE) after which apo-cholesterol oxidase (apo-ChOx) was immobilized onto a flavin adenine dinudeotide (FAD) monolayer by reconstitution method. In this study two well-known and widely used materials in the field of biosensors thiophene-3-boronic acid and 3-aminophenyl boronic acid were electropolymerized onto PGE and modified with cholesterol oxidase. Electrochemical performance of modified electrodes and their properties were compared. Based on the results, thiephene-3-boronic acid based electrode shows sensitivity 10 times higher response than that of one based on 3-aminophenyl boronic add. The effect of pH and temperature were assessed as well the reusability and stability of the fabricated biosensor were discussed. (C) 2016 Elsevier B.V. All rights reserved.

In this paper, a novel amperometric xanthine (X) biosensor is constructed by xanthine oxidase (XOx) immobilization on the pencil graphite electrode (PGE). Xanthine oxidase is immobilized using glutaraldehyde (GA) on the electrochemically polymerized conducting polymer film. The detection of xanthine is based on its consumed amount due to the enzymatic reaction of xanthine oxidase. The effects of polymer thickness, applied potential, pH, and temperature were investigated and optimum parameters were found to be five cycles, +5V, +0.5V and 30 degrees C, respectively. Storage stability, operation stability of the enzyme electrode, and effect of interferant substances on the amperometric response were also studied. In order to verify the applicability of proposed biosensor, fabricated electrode was used to measure the xanthine concentration in chicken meat samples. The present xanthine biosensor with high selectivity, sensitivity, and stability is promising for practical applications. (C) 2015 Elsevier B.V. All rights reserved.

In this work, super paramagnetic magnetite nanoparticles were synthesized onto/into zeolite, then loaded with anti-cancer drug 5-fluorouracil (5-FU). The physical properties of the prepared nanocomposite and drug loaded nanocomposite were characterized using different techniques. The drug loading and releasing behavior of the magnetic nanocarrier was investigated and the drug-loaded nanoparticles exhibited a sustained release of drug without any burst release phenomenon. Furthermore, 5-FU loaded MZNC were evaluated for its biological characteristics. The functional 5-FU-MZNC has been triggered intra-cellular release of the cancer therapeutic agent 5-fluorouracil (5-FU). Cytotoxic effects of 5-FU loaded MZNC on human gastric carcinoma (AGS) cells were determined by real time cell analysis and colorimetric WST-1 cell viability assay. Apoptosis of cells was further investigated by Annexin-V staining which indicates the loss of cell membrane integrity. According to our results, 5-FU-MZNC showed a concentration-dependent cell proliferation inhibitory function against AGS cells. Morphologic and apoptotic images were consistent with the cytotoxicity results. In conclusion, 5-FU loaded MZNC efficiently inhibit the proliferation of AGS cells in vitro through apoptotic mechanisms, and may be a beneficial agent against cancer, however further animal study is still required. (C) 2015 Elsevier Masson SAS. All rights reserved. Bezmiâlem Vakıf Üniversitesi

In this study, a photo-bioelectrochemical fuel cell was constructed for photocurrent generation by illuminating the electrodes within an aqueous solution. In this purpose, gold electrode was coated with poly 4-(4H-Dithieno [3,2-b:2',3'-d]pyrol-4-yl) aniline, P(DTP-Ph-NH2) conductive polymer film by using electrochemical polymerization. Then, P(DTP-Ph-NH2) conductive polymer film coated surface was electrochemically modified with cytochrome C which covalently linked onto the surface via bis-aniline functionality of the polymer film and formed crosslinked-structure. The thylakoid membrane was attached on the surface of this electrode by using bissulfosaxinimidyl suberate (BS3) and used as photo-anode in photo-bioelectrochemical fuel cell. The photo-cathode of the photo-bioelectrochemical fuel cell fabrication was followed by the modification of conductive polymer poly[5-(4H-dithieno [3,2-b:2',3'-d]pyrol-4-yl) naphtalene-1-amine] film coating, glutaraldehyde activation, and bilirubin oxidase enzyme immobilization. During the photosynthesis occurring in thylakoid membrane under the light, water was oxidized and separated; while oxygen was released in anode side, the cathode side was reduced the oxygen gas into the water via a bio-electro-catalytic method. The cytochrome C was used for binding of thylakoid membrane to the electrode surface and play an important role for transferring of electrons released as a result of photosynthesis.

In this study, xanthine molecules which can serve as an indicator of meat spoilage were determined using a novel and sensitive amperometric xanthine biosensor. Biosensor was developed by preparing a nanocomposite film that was constructed by embedding reduced expanded graphene oxide (REGO) sheets decorated with iron oxide (Fe3O4) nanoparticles into poly(glycidyl methacrylate-covinylferrocene) (P(GMA-co-VFc)) phase, and by covalent immobilization of Xanthine oxidase (XOD) on the surface of P(GMA-co-VFc)/REGO-Fe3O4 nanocomposite film. Bio-analytical optimal experimental conditions such as response time, linear range, operation and storage stability, working pH and temperature were studied. Current response of linear range was detected in the range of 2-36 mu M with a sensitivity of 0.17 mu A/M, response time of similar to 3 s, and detection limit of 0.17 mu W. The resulting bionanocomposite xanthine biosensor was subjected to fish real sample testings where 5, 8, 10, 13, 15, and 20 days-old fish samples- xanthine content was measured. The developed biosensor was found to be applicable to real samples as a very reliable fish freshness controlling technique. (C) 2015 Elsevier Ltd. All rights reserved. Bezmiâlem Vakıf Üniversitesi

A novel nanocomposite host matrix for enzyme immobilization of xanthine oxidase was developed by incorporating MWCNT in poly(GMA-co-VFc) copolymer film. In the food industry fish is a product with a very low commercial life, and a high variability as well elevated level of xanthine is an important biomarker as a sign of spoilage. The fabricated process was characterized by scanning electron microscopy (SEM), and the electrochemical behaviors of the biosensor were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The prepared enzyme electrodes exhibited maximum response at pH 7.0 and 45°C +0.35 V and reached 95% of steady-state current in about ∼ 4 s and its sensitivity was 16 mAM(-1). Linear ranges (2-28 μM, 28-46 and 46-86 μM), analytical performance and a low detection limit 0.12 μM obtained from the xanthine biosensor gives reliable results in measuring xanthine concentration in the fish meat. All the results indicating that the resulting biosensor exhibited a good response to xanthine that was related to the addition of MWCNT in the polymeric mediator film which played an important role in the biosensor performance. In addition, the biosensor exhibited high good storage stability and satisfactory anti-interference ability.

In this study, a novel glucose biosensor was fabricated by reconstitutional immobilization of glucose oxidase (GOx) onto a poly(glycidyl methacrylate-co-vinylferrocene) (poly(GMA-co-VFc)) film coated pencil graphite electrode (PGE). The amperometric current response of poly(GMA-co-VFc)-GOx to glucose is linear in the concentration range between 1 and 16 mM (correlation coefficient of 0.9998) with a detection limit of 2.7 μM ( S / N = 3). Experimental parameters were studied in detail and optimized, including the pH and temperature governing the analytical performance of the biosensor. The stability and reusability of the biosensor as well as its kinetic parameters have also been studied.

Organik gıdalara olan talep ve organik gıda tüketiminin popülaritesi her geçen gün artmaktadır. Organik gıdaları tüketmek ülkemizde yalnızca belirli bir kitlenin benimsediği bir yaşam tarzına özgü olmaktan çıkmış ve artık birçok Türk tüketicinin ortak noktası haline gelmiştir. Buna rağmen düzenli olarak organik gıda satın alan Türk tüketicilerin motivasyonları hakkında bilinenler oldukça azdır. Bu çalışmada Zaltman Metafor Çıkarım Tekniği kullanılarak sekiz Türk tüketici ile görüşülmüştür. Bu çalışmada uygulanan metafor analizi, organik gıda tüketen tüketicilerin motivasyonlarının anlaşılmasına katkı sağlamaktadır. Analiz sonuçlarına göre; üç derin metafor (bireysel perspektif, toplumsal perspektif ve kazanım/fayda), dokuz tematik kategori (sağlıklı yaşam, sosyal statü aracı, lezzete düşkünlük, doğaya uyumlu yaşama, geçmişe duyulan özlem, çevre bilinci, kültürü yansıtması, yerel ekonomiye destek, iyi hissetme) ve dokuz kavramsal metafor (kalkan, burjuvazi, gurme, doğasever, gelenekçi, koruyucu melek, ayna, tutucu, anti-depresan) ortaya çıkarılmıştır.

The surface modification of nano-hydroxyapatite with polyamidoamine (PAMAM) dendrimer has potential for biomedical applications due to their unique and well-defined secondary structures. This paper presents a facile method to synthesize siloxane-cored PAMAM dendrons modified Hydroxyapatite nanoparticles. Firstly, the siloxane-cored PAMAM dendrons with different generations (G1 to G5, respectively) were synthesized using repetitive reactions between Michael addition and amidation starting from 3-aminopropyltriethoxysilane. Then, hydroxyapatite nanoparticles were synthesized by hydrothermal crystallization method and functionalized with siloxane-cored PAMAM dendrons. These synthesized materials were characterized by using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA). The results showed that the PAMAM dendrimer functionalization was carried out successfully and these materials may be applicable in biocomposite material and/or bone tissue engineering.

In this study, three different types of scaffolds including a uniquely modified composite scaffold - namely chitosan (CTS), nano-hydroxyapatite/chitosan composite (CTS + nHAP), and amine group (NH2) modified nano-hydroxyapatite/chitosan composite (CTS + nHAP-NH2) scaffolds- were synthesized for bone tissue engineering (BTE) purposes. As results of the study, it was found that all scaffold types were biodegradable with CTS and CTS + nHAP scaffolds losing up to 15% of their initial weight, while the CTS + nHAP-NH2 scaffold showing 10% of weight loss after six weeks of lysozyme treatment. In addition, all three types of scaffolds were shown to be biocompatible, and amongst them CTS + nHAP-NH2 scaffolds supported the most cell proliferation in WST-1 assay and expressed the least and acceptable level of cytotoxicity in lactate dehydrogenase (LDH) test for human bone mesenchymal stem cells (hBM-MSCs). Finally, during osteoinductivity assessment, CTS + nHAP-NH2 nearly tripled initial alkaline phosphatase (ALP) activity when whereas both CTS and CTS + nHAP scaffolds only doubled. These results indicate that all synthesized scaffold types under investigation have certain potential to be used in bone tissue engineering approaches with CTS + nHAP-NH2 scaffold being the most promising and applicable one. In the future, we plan to intensify our studies on osteogenic differentiation on our scaffolds on a detailed molecular level and to include in vivo studies for pre-clinical purposes. (C) 2017 Elsevier Ltd. All rights reserved. Türkiye Bilimsel Ve Teknolojik Araştırma Kurumu ( Tübitak )

In this study, polyamidoamine (PAMAM) dendrimer coated superparamagnetite nanoparticles were synthesized by growing of PAMAM on amino-silane coated iron oxide nanoparticles. The PAMAM modified superparamagnetite nanoparticles were used as reversible protein immobilization host materials. During the reversible immobilization studies the effect of different metal ions such as; Cu +2 , Zn +2 , Co +2 , Ni +2 on immobilization efficiency of BSA were evaluated. The maximum BSA adsorption capacity of the PAMAM-MNP- Cu +2 beads was observed to be 52.84 mg/g (BSA/PAMAM-MNP) at pH 7.0. Various characteristics of immobilized BSA such as; effect of generation, effect of pH, BSA concentration, temperature, salt concentration and reusability of PAMAM-MNP were evaluated.

Polyvinylimidazole (PVI)-grafted iron oxide nanoparticles (PVIgMNP) were prepared by grafting of telomere of PVI on the iron oxide nanoparticles. Crystalline phase was identified as magnetite with an average size of 9 nm estimated from X-ray line profile fitting. Particle size estimated from TEM by log-normal fitting was ∼10 nm. FT-IR analysis showed that the binding of silane onto the surface of iron oxide is through unidentate linkage of Si–O. The AC characteristics of nanocomposites were analyzed via the capacitive impedance measurement method. And the effective conduction mechanism was found as correlated barrier hopping. dc activation energy of the product at around room temperature was found between 0.216 and 0.776 eV in good agreement with the earlier reports. It is found that the molar ratio of AA/PVI is effective on the DC conductivity and Activation energy of composites. The effects of grafting and alginic acid/polyvinylimidazole molar ratio on conduction mechanism were studied.

The biosensor was constructed for determination of glucose by using glucose oxidase enzyme immobilized on poly(thiophene-3-boronic acid) (PTBA). Boronic acid functionalized polythiophene layer was obtained by electrochemical polymerization of Thiophene (Th) and thiophene-3-boronic acid (TBA) with different monomer rations. The reconstitution of the apo-glucose oxidase (apo-GOx) on a complexed flavin adenine dinucleotide (FAD) linked to polythiophene boronic acid (PTBA) monolayer yields an electrically contacted enzyme monolayer. The GOx-reconstituted enzyme electrode exhibited excellent electrocatalytic activities toward the reduction and oxidation of hydrogen peroxide as well. The PTBA/FAD/GOx biosensor shows an excellent performance for glucose at +0.4 V with a high sensitivity (2.14 μA/mM) and lower response time (∼5 s) in a wide concentration range of 0.5–18 mM (correlation coefficient of 0.9952). Furthermore, the effects of applied potential, pH, temperature, electroactive interference, stability and reusability of the biosensors were discussed.

Nanocomposites of Polyacrylic acid/polyvinylimidazole (PAA/PVI) with grafted and ungrafted iron oxide nanoparticles were prepared by a Reflux method. The Fe3O4 nanoparticles with 10 nm average diameter were synthesized by controlled co-precipitation and silanization of Si-PVI on Fe3O4 was used to obtain the grafted ones. Grafting becomes important at composites of less PVI that cause drastic decreases in AC conductivity. The content of PVI has important effects on the conductivity mechanism of these composites. The effect of grafting and Polyacrylic acid/polyvinylimidazole molar ratio on the conduction mechanism were studied. The conduction mechanism of iron oxide nanocomposites can be adjusted by changing molar ratio of Polyacrylic acid/polyvinylimidazole and grafting of Fe3O4NPs.

Highlights: • Polyacrylamide (PAAm) hydrogels containing magnetic BaFe{sub 12}O{sub 19} nanoparticles have been prepared. • Magnetization measurements reveal that hydrogels have hard magnetic properties with high coercivity. • Magnetic nanoparticles makes the gel more homogeneous and do not diffuse out of the gel during water intake. • These gels are useful in applications as wastewater treatment once gels are magnetized before its usage. - Abstract: This study investigates the synthesis and characterization of polyacrylamide (PAAm) hydrogels containing magnetic BaFe{sub 12}O{sub 19} nanoparticles. Structural, electrical, and magnetic characterization of the gels have been performed with X-ray powder diffractometry, scanning electron microscopy, DC conductivity, magnetization and fluorescence spectroscopy techniques. The preparation and characterization of polyacrylamide (PAAm) hydrogels that contain 5 and 10 mg BaFe{sub 12}O{sub 19} (16 and 21 nm diameter) nanoparticles are described herein. It is seen from the fluorescence spectra that, nanoparticles surrounded to pyranine molecules so that some of pyranine molecules could not bound to the polymer strands. Electrical measurements show that presence of nanoparticles make the gel more homogeneous. Magnetization measurements reveal that hydrogels have hard magnetic properties with quite high coercivity of 4.2 kOe, which does not change with swelling. This feature makes these gels useful inmore » applications as wastewater treatment if they are magnetized before use.« less

The aim of the present study was to evaluate the aqueous solubility enhancement properties of polypropylene oxide cored PAMAM (PPO@PAMAM) dendrimers. The solubility of NSAIDs (Ketoprofen, Ibuprofen and Diflunisal) was investigated in the presence of PPO@PAMAM dendrimers at room temperature in buffer solution. The effects of dendrimer concentration, generation and core size on the solubility of NSAIDs have been investigated. The experimental results showed that the solubility of the NSAIDs was approximately proportional to dendrimer concentration and generation. In addition, the effect of core size on the solubility of NSAIDs in constant generation and concentration of PPO@PAMAM dendrimer was Ketoprofen > Diflunisal > Ibuprofen. Under optimized conditions, PPO@PAMAM dendrimers are highly effective solubility enhancer for NSAIDs due to its new polypropylene oxide core.

Department of Genetics and Bioengineering, Faculty of Engineering, Fatih University, B.Cekmece, Istanbul 34500,Turkey*e-mail: msenel@fatih.edu.tr; cnergiz@fatih.edu.trReceived: October 4, 2012Accepted: December 25, 2012Published online: April 2, 2013AbstractAn amperometric biosensor for determining glucose based on deflavination of the enzyme glucose oxidase and sub-sequent reconstitution of the apo-protein with a complexed flavin adenine dinucleotide (FAD) monolayer is de-scribed. The GOx-reconstituted electrode exhibited excellent electrocatalytic activities towards the reduction andoxidation of hydrogen peroxide as well. The prepared biosensor showed an excellent performance for glucose at+0.5 V with a high sensitivity (5.94 mA/mM) and relatively good response time (~12 s) in a wide concentrationrange of 1–17 mM (correlation coefficient of 0.9998). The applicability to blood analysis was also evaluated.Keywords: Polyaniline, Glucose Oxidase, Biosensor, Boronic acidDOI: 10.1002/elan.201200535

In this study, Fe3O4 (magnetite) nanoparticles were synthesized by in situ in polyacrylamide (PAAm) gels. Structural and magnetic properties of magnetite nanoparticles were investigated by X-Ray diffractometry (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM) methods. Interaction of pyranine molecules with Fe3O4 nanoparticles was investigated by fluorescence spectroscopy measurements in which pyranine (POH) molecules were used as a flouroprobe. It was observed that magnetite nanoparticles have single domain structure with average grain size of 12 nm which was also supported by magnetization measurements. M-H hysteresis curves revealed the superparamagnetic nature of magnetite nanoparticles synthesized in PAAm gels. Fluorescence measurements depicted that there is an interaction between POH and magnetite nanoparticles which was deduced from the presence of two new peaks at 380 nm and 405 nm in emission spectrum. Besides, it was observed that POH molecules could not diffuse into the gel when it consists of magnetite nanoparticles which also make the gel more homogeneous. As swelling ratio increases from 1 to 13, magnetization of the gel does not change which reveals that magnetic nanoparticles do not diffuse out of the gel during water-intake. This feature makes the gel suitable for applications as waste water treatments. (C) 2013 Elsevier B.V. All rights reserved.

A functionalized multiwall carbon nanotube (MWCNT)–COOH/Fe3O4 hybrid was fabricated by co-precipitation method. Fe3O4 nanoparticles were stably attached to the surface of carboxyl groups (COOH). The presence of Fe3O4 nanoparticles and their surface conjugation to MWCNT have been confirmed by XRD, TEM and FT-IR techniques. Magnetic evaluation revealed a superparamagnetic character of the hybrid and therefore the attached Fe3O4 nanoparticles. The crystallite size (9 ± 3 nm), particle size (9 ± 2 nm) and magnetic domain size estimated for Fe3O4 are consistent with each other, which reveal the single crystalline character of the nanoparticles. Electrical conductivity and dielectric behavior have also been characterized by utilizing impedance spectroscopy up to 3 MHz for an isotherm line varying from 293 to 393 K by 10 K steps. Electrical characteristics and its complex dielectric approaches might be elucidated with the existence of a conventional tunneling conduction mechanism of temperature-independency. The AC conductivity of MWCNT–COOH/Fe3O4 hybrid could also be a consequence of the estimations of the universal dynamic response.

Novel series of asymmetric Poly(amidoamine) (PAMAM) dendrons containing a single ferrocene unit located as the focal point has been prepared. First, second, and third generation ferrocene-PAMAM dendrons with branched amine periphery and focal ferrocene functionality were synthesized via divergent pathways. The synthesized dendrons were characterized by FT-IR and NMR spectroscopy. Real-time cell analysis, cell viability, and anti-cancer activity of ferrocene-PAMAM dendrons were evaluated in AGS cells. While cell viability decreased, anti-cancer activity increased gradually in a dose-dependent manner in one, two, and three generations.

Urease enzyme was covalently attached on the poly(glycidylmethacrylate) (PGMA)-grafted iron oxide nanoparticles on Au electrode for the fabrication of urea biosensor. The telomere of poly(glycidylmethacrylate) (PGMA) with a trimethoxysilyl terminal group was synthesized by telomerization of glycidylmethacrylate. Iron oxide nanoparticles were coated with telomere of poly(glycidylmethacrylate) in order to obtain good enzyme immobilization platform. The telomere and nanoparticles were characterized by using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA). The biosensor’s potentiometric response was measured as a function of urea concentration in phosphate buffer solution (10 mM, pH 7.5) and showed a linear range of 0.25–5.0 mM urea. The produced biosensor exhibited a good response time of ∼8 s and was stable for about two months. The basic features (optimum pH, optimum temperature, interference and storage stability) of the enzyme electrode were determined.

A novel amperometric glucose biosensor is fabricated with immobilization of glucose oxidase (GOx) onto PAMAM-Fc dendrimers decorated gold electrode. Series of asymmetric PAMAM dendrimers containing a single ferrocene unit located in the focal point of these macromolecules have been synthesized and characterized. Surface of the gold electrode was covalently modified with 3-mercaptopropionic acid, PAMAM-Fc dendrimers and GOx enzyme by using coupling agents, respectively. The PAMAM-Fc/GOx biosensor shows an excellent performance for glucose at +0.25 V with a high sensitivity (6.54 μA/mM) and lower response time (∼3 s) in a wide concentration range of 1–22 mM (correlation coefficient of 0.9988). In addition, PAMAM-Fc/GOx biosensor possesses better reproducibility, storage stability and there is negligible interference from other electroactive components.

Acid functionalized multiwall carbon nanotube, (MWCNT)-COOH/nickel ferrite (NiFe2O4), magnetic hybrids were synthesized by a co-precipitation method. X-ray diffraction, Fourier transform infrared spectrometry, thermal gravimetry, transmission electron microscopy, vibrating sample magnetometry and Impedance Spectroscopy were used to characterize the physical and electrical properties of the MWCNT-COOH/NiFe2O4 hybrid. NiFe2O4 NPs are stably attached to the surface of via carboxyl groups (COOH). The magnetic saturation value of the product was found as 8 emu/g. A tunneling conduction mechanism was believed to occur in the hybrid. The real modules (M') of the product illustrate power law variation with a power exponent of approximately unity. These magnetic MWCNT-COOH/NiFe2O4 hybrids exhibit a promising prospective in the application of bio-nanoscience and technology.

The detection of cancer cells through important molecular recognition target such as sialic acid is significant for the clinical diagnosis and treatment. There are many electrochemical cytosensors developed for cancer cells detection but most of them have complicated fabrication processes which results in poor reproducibility and reliability. In this study, a simple, low-cost, and highly sensitive electrochemical cytosensor was designed based on boronic acid-functionalized polythiophene. In cytosensors fabrication simple single-step procedure was used which includes coating pencil graphite electrode (PGE) by means of electro-polymerization of 3-Thienyl boronic acid and Thiophen. Electrochemical impedance spectroscopy and cyclic voltammetry were used as an analytical methods to optimize and measure analytical performances of PGE/P(TBA0.5Th0.5) based electrode. Cytosensor showed extremely good analytical performances in detection of cancer cells with linear rage of 1×101 to 1×106 cellsmL-1 exhibiting low detection limit of 10 cellsmL-1 and incubation time of 10min. Next to excellent analytical performances, it showed high selectivity towards AGS cancer cells when compared to HEK 293 normal cells and bone marrow mesenchymal stem cells (BM-hMSCs). This method is promising for future applications in early stage cancer diagnosis.