Search results for "electrochemical"
showing 10 items of 574 documents
Highly selective detection of Epinephrine at oxidized Single-Wall Carbon Nanohorns modified Screen Printed Electrodes (SPEs)
2014
Oxidized Single-Wall Carbon Nanohorns (o-SWCNHs) were used, for the first time, to assemble chemically modified Screen Printed Electrodes (SPEs) selective towards the electrochemical detection of Epinephrine (Ep), in the presence of Serotonine-5-HT (S-5HT), Dopamine (DA), Nor-Epineprhine (Nor-Ep), Ascorbic Acid (AA), Acetaminophen (Ac) and Uric Acid (UA). The Ep neurotransmitter was detected by using Differential Pulse Voltammetry (DPV), in a wide linear range of concentration (2-2500 μM) with high sensitivity (55.77 A M(-1) cm(-2)), very good reproducibility (RSD% ranging from 2 to 10 for different SPEs), short response time for each measurement (only 2s) and low detection of limit (LOD=0.…
Optical and electrochemical DNA nanobiosensors
2011
In the past two decades, nanoscale advanced materials have been explored for biosensing molecules, so new horizons have opened up for identifying and quantifying biomolecules, and possible early diagnosis of diseases. DNA nanobiosensors show promise. This article provides an overview on their optical and electrochemical aspects. We discuss recent progress in this field, describing basic concepts of molecular beacons and quantum dots as optical nano-imaging systems. Also, carbon nanotubes provide a platform for development and advancement of electrochemical DNA nanobiosensors, which are increasingly being implemented as robust tools for detection in biomedical sciences. Refereed/Peer-reviewed
Development of a nanostructured sensor for monitoring oxidative stress in living cells
2018
Oxidative burden is elevated in the lung of COPD patients and is associated with aging and chronic inflammation. When overcoming physiological levels, reactive oxygen species (ROS) cause cell damage and sustain inflammation. Both lung epithelium and alveolar macrophages contribute to ROS generation. Currently, ROS generation is measured using fluorescent probes and colorimetric/fluorimetric assays. We present an amperometric nanostructured sensor for real-time detection of hydrogen peroxide (H2O2) released by living cells. The H2O2 sensing performance was evaluated through the current vs time response of platinum rod at a working potential of −0.45 V vs saturated calomel electrode acting as…
Electrochemical sensor based on rGO/Au nanoparticles for monitoring H2O2 released by human macrophages
2021
Abstract Increased oxidative burden contributes to the pathogenesis of most inflammatory diseases and is associated with aging and chronic inflammation. Macrophages contribute to the generation of reactive oxygen species (ROS) within inflamed tissues. Currently, ROS generation is measured using fluorescent probes and colorimetric/fluorimetric biochemical assays. Hydrogen peroxide (H2O2) diffuses through the cell membrane and can be monitored in the extracellular space. Herein, we present a sensor for H2O2 detection released by cells in culture supernatants. H2O2 sensing performance was evaluated using chronoamperometric detection. A sensitivity of 0.0641 μA μM−1 cm−2 with a limit of detecti…
Copper nanowire array as highly selective electrochemical sensor of nitrate ions in water
2020
Contamination of water with nitrate ions is a significant problem that affects many areas of the world. The danger from nitrates is not so much their toxicity, rather low, as their transformation into nitrites and in particular into nitrosamines, substances considered to be a possible carcinogenic risk. For this reason, European legislation has set the maximum permissible concentration of nitrates in drinking water at 44 mg/l. Thus, it is clear that a continuous monitoring of nitrate ions is of high technological interest but it must be rapid, easy to perform and directly performed in situ. Electrochemical detection is certainly among the best techniques to obtain the above requirements. In…
Electrochemical biosensing using N-GQDs: Recent advances in analytical approach
2018
Abstract This review is meant to provide an overview of the electrochemical biosensors based on Nitrogen doped graphene quantum dots (N-GQDs) for analytical approaches, along with significant advances over the last several years in related technologies. In addition, this review described: i) Most frequently applied principles in biosensing based on of N-GQDs ii) The aspects of fabrication in the perspective of biosensing applications iii) The potential of various electrochemical, biosensors for the determination of target analytes within sub-micromolar range and the circumvention of the most serious problem in biosensing will be discussed. iv) Some of multiplex electrochemical biosensors ha…
Toward large-area targets for “TRAKULA”
2011
Abstract TRAKULA ( Tra nsmutationsrelevante k ernphysikalische U ntersuchungen l anglebiger A ktinide, i.e., nuclear physical investigations of long-lived actinides with relevance to transmutation) is a joint research project of the German Federal Ministry of Science and Education (BMBF) on nuclear physics investigations with modern scientific, technological and numerical methods. Experiments concerning the transmutation of radioactive waste are a central topic of the project. For this, large-area samples (≥40 cm 2 ) of 235,238 U and 239,242 Pu compounds are required for the calibration of fission chambers and for fission yield measurements. Another topic within the project requires large-a…
Concatenated logic functions using nanofluidic diodes with all-electrical inputs and outputs
2018
[EN] Nanopore-based logical schemes in ionic solutions typically involve single gates and chemical inputs. The design of computer-like functions requires the consecutive concatenation of several gates and the use of electrical potentials and currents to facilitate the downstream transfer of electrochemical information. We have demonstrated the robust operation of concatenated logic functions using biomimetic nanofluidic diodes based on single pore membranes. To this end, we have implemented first the logic functions AND and OR with combinations of single nanopores using all-electrical input and output signals. The concatenation of these gates allows the output of the OR gate to act as one o…
Homogeneous Metal-Based Catalysis in Supercritical Carbon Dioxide as Reaction Medium
2016
Above 31.1 degrees C and 73.8 bar, carbon dioxide reaches the supercritical state, being transformed into a fluid (scCO(2)) that has attracted interest in the last few decades as reaction medium for several transition-metal-catalyzed organic transformations. The main feature of this fluid rests on its capability to dissolve large amounts of other gases such as hydrogen, carbon monoxide, ethylene, or even methane and light alkanes. In this manner, very high concentrations of these reactants are available for catalysis. In this contribution a review of the main achievements of the use of transition-metal complexes as catalysts in scCO(2) is presented.
Nanomaterial-based cocaine aptasensors.
2015
Up to now, many different methods have been developed for detection of cocaine, but most of these methods are usually time-consuming, tedious and require special or expensive equipment. Therefore, the development of simple, sensitive and rapid detection methods is necessary. In the last decade, aptamers have been used as a new biosensor platform for detection of cocaine in different samples. Aptamers are artificial single-stranded DNA or RNA oligonucleotides capable of binding to specific molecular targets with high affinity and if integrated to nanomaterials, it may lead in precise methods for cocaine detection in the common laboratories. In this review, recent advances and applications of…