1,721,027 research outputs found
Diiron Complexes with Bridging Hydrocarbyl Ligands as Electrocatalysts for Proton Reduction
No full textMicro- and nano-devices for electrochemical sensing
Full text linkElectrode miniaturization has profoundly revolutionized the field of electrochemical sensing, opening up unprecedented opportunities for probing biological events with a high spatial and temporal resolution, integrating electrochemical systems with microfluidics, and designing arrays for multiplexed sensing. Several technological issues posed by the desire for downsizing have been addressed so far, leading to micrometric and nanometric sensing systems with different degrees of maturity. However, there is still an endless margin for researchers to improve current strategies and cope with demanding sensing fields, such as lab-on-a-chip devices and multi-array sensors, brain chemistry, and cell monitoring. In this review, we present current trends in the design of micro-/nano-electrochemical sensors and cutting-edge applications reported in the last 10 years. Micro- and nanosensors are divided into four categories depending on the transduction mechanism, e.g., amperometric, impedimetric, potentiometric, and transistor-based, to best guide the reader through the different detection strategies and highlight major advancements as well as still unaddressed demands in electrochemical sensing. GRAPHICAL ABSTRACT: [Image: see text
Analytical performances of Ni LDH films electrochemically deposited on Pt surface: phenol and glucose detection
No full textNi/Al Layered Double Hydroxide thin films have been prepared by electochemical deposition on Pt electrodesNi/Al Layered Double Hydroxide (LDH) thin films have been prepared by electrochemical deposition on Pt electrodes, with the aim to study the performances of the coated electrodes as sensors for phenol and glucose detection. The electrochemical behavior of the devices has been assessed and the adhesion of the coatings evaluated since this parameter plays an important role for the long term performance of the sensor. In particular adhesion has been studied as a function of the Pt surface features which depend on the electrode pretreatment
Beyond the iron-dithiolate mimics paradigm: diiron complexes with m-carbyne ligands as electrocatalyst for proton reduction
No full textElectrochemical Deposition of Nanomaterials for Electrochemical Sensing
No full textThe most commonly used methods to electrodeposit nanomaterials on conductive supports or to obtain electrosynthesis nanomaterials are described. Au, layered double hydroxides (LDHs), metal oxides, and polymers are the classes of compounds taken into account. The electrochemical approach for the synthesis allows one to obtain nanostructures with well-defined morphologies, even without the use of a template, and of variable sizes simply by controlling the experimental synthesis conditions. In fact, parameters such as current density, applied potential (constant, pulsed or ramp) and duration of the synthesis play a key role in determining the shape and size of the resulting nanostructures. This review aims to describe the most recent applications in the field of electrochemical sensors of the considered nanomaterials and special attention is devoted to the analytical figures of merit of the devices
Recent progress in wearable fully textile chemical sensors
No full textIn the new era of Internet of Things, there is a great demand for the development of novel chemical wearable sensors, in particular, for personalized medical diagnostics with point-of-care devices. This paper provides an overview on the recent developments in this field, focusing on fully textile chemical sensors, i.e., sensors directly incorporated into a garment/fabric/ fiber. The recent results are summarized by grouping them in three broad categories according to their working principle: (i) electrochemical sensors; (ii) transistor-based sensors; and (iii) resistance-based sensors. Wearable chemical sensors can be used to detect external dangerous vapor/agents, or to control and monitor the concentration of specific compounds in biofluids for safety and healthcare applications. One of the main issues of such applications is sensor operation in a complex medium containing many interfering compounds. To this end, recent novel approaches to enhance the selectivity of fully textile wearable sensors are reviewed: enzyme-based approach, selective membrane, and a potentiodynamic method. Finally, a critical overview is given about the major open issues that have to be overcome in order to reach a high technology readiness level
Assessment of the Antioxidant Capacity of Standard Compounds and Fruit Juices by a Newly Developed Electrochemical Method: Comparative Study with Results from Other Analytical Methods
No full textThe antioxidant capacity (AOC) of some standard compounds and commercial beverages was determined using an electroanalytical method which measures the OH radical scavenging ability (OH-RSC). It is based on the degradation of a thin polyphenol film electrodeposited on glassy carbon following the attack by OH radicals produced by hydrogen peroxide photolysis. The degradation is prevented in presence of increasing concentrations of antioxidants. The same samples were also analyzed by DPPH, ABTS, and ORAC assays. The OH-RSC method provided AOC values highly correlated with those resulting from the application of ORAC assay for both juices (R=0.90) and standard antioxidants (R= 0.96)
Focus Review on Nanomaterial-Based Electrochemical Sensing of Glucose for Health Applications
Full text linkDiabetes management can be considered the first paradigm of modern personalized medicine. An overview of the most relevant advancements in glucose sensing achieved in the last 5 years is presented. In particular, devices exploiting both consolidated and innovative electrochemical sensing strategies, based on nanomaterials, have been described, taking into account their performances, advantages and limitations, when applied for the glucose analysis in blood and serum samples, urine, as well as in less conventional biological fluids. The routine measurement is still largely based on the finger-pricking method, which is usually considered unpleasant. In alternative, glucose continuous monitoring relies on electrochemical sensing in the interstitial fluid, using implanted electrodes. Due to the invasive nature of such devices, further investigations have been carried out in order to develop less invasive sensors that can operate in sweat, tears or wound exudates. Thanks to their unique features, nanomaterials have been successfully applied for the development of both enzymatic and non-enzymatic glucose sensors, which are compliant with the specific needs of the most advanced applications, such as flexible and deformable systems capable of conforming to skin or eyes, in order to produce reliable medical devices operating at the point of care
Amperometric biosensors based on reduced GO and MWCNTs composite for polyphenols detection in fruit juices
No full textAmperometric biosensors based on glassy carbon electrodes (GCE) modified with graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) were developed. Two types of biosensors were realized employing tyrosinase (Tyr) or laccase (Lac). Before enzyme deposition GO was reduced by electrochemical route performing cyclic voltammetry. The enzyme immobilisation on the modified GC was optimised employing different agents (bovine serum albumin and glutaraldehyde as crosslinking agent, chitosan, and Nafion). The conditions for the fabrication and the storage of the biosensors were established in order to obtain good enzyme retention, high sensitivities and long-life devices. The biosensors were used for the determination of catechol and other polyphenols, i.e., pyrogallol, epicatechin, gallic acid, 1,2-dihydroxybenzoic acid, caffeic acid, chlorogenic acid, rutin, catechin and dopamine. Eventually, their practical applicability was demonstrated by estimating the total polyphenols concentration in juice samples, expressed as epicatechin equivalents
- …
