1,721,101 research outputs found
Laccase and tyrosinase on electrochemically reduced GO and MWCNTs hybrid for the development of polyphenols biosensors
No full textA new electrochemical sensor for OH radicals detection
No full textA new, cheap modified electrode for indirect detection of OH radical is described. A glassy carbon (GC) electrode was modified with a polyphenol film prepared by oxidative potentiostatic ectropolymerization of 0.05 M phenol in 1 M H2SO4. The film having a thickness of ~10 nm perfectly covered the GC surface and inhibited the charge transfer of many redox species. The degradation of the polyphenol film, that was induced by OH radicals generated by Fenton reaction or by H2O2 photolysis, is the analytical signal and it was evaluated by cyclic voltammetry and chronoamperometry using the redox probe Ru(NH3)63+. Some simulations of the kinetics of the reactions occurring in the solution bulk and near the electrode surface were carried out to fully understand the processes that lead to the analytical signal. The modified electrode was used to evaluate the performances of different TiO2-based photocatalysts and the results were successfully compared with those obtained from a traditional HPLC method that is based on the determination of the hydroxylation products of salicylic acid
Carbon nanomaterials as glassy carbon modifiers for electrochemical devices with boosted activity
Full text linkGlassy carbon electrodes (GCEs) modified with a composite made of multi-walled carbon nanotubes (MWCNTs)
and electrochemically reduced graphene oxide (ERGO) were employed to investigate the electroactivity of
dopamine (DA) an catechol (CA) which resulted into a significant improvement of the analytical performances.
The same composite was used to support tyrosinase or laccase in order to fabricate amperometric biosensors for
determining total polyphenols in juice samples, based on the reduction of the enzymatically produced quinone.
Carbon based nanomaterials were also exploited to induce the electrosynthesis of layered double hydroxides
(LDHs). Using glucose as target, electrocatalytic activity was found to be higher than when LDH was deposited on
bare GCE
Layered Double Hydroxides Prepared by Electrodeposition as Active Materials for Energy Applications
No full textElectrosynthesis of Layered Double Hydroxides as active materials for sensing, energy, and catalysis
No full text
Design of an electrochemically gated organic semiconductor for pH sensing
Full text linkSince the development of potentiometric ion-selective electrodes, remarkable steps have been taken towards progressive simplification and improved robustness of pH sensing probes. In particular, the design of compact sensing architectures using solid-state components holds great potential for portable and wearable applications. Here we report the development of an electrochemically gated device for pH detection, combining the robustness of potentiometric-like transduction with an extremely simple and integrated geometry requiring no reference. The sensor is a two-point probe device comprising two thin polymeric films, i.e. a charge transport layer and a pH-sensitive layer, and exhibits a sensitivity of (8.3 ± 0.2) × 10−3 pH unit−1 in the pH range from 2 to 7. Thanks to the versatility and robustness of the optimised design, a textile pH sensor was fabricated whose performance is comparable with that of glass sensors
Wearable Textile Sensors for Uric Acid Detection in Wound Exudate
No full textHard-to-heal wounds (i.e. severe and/or chronic) are typically associated with particular pathologies or afflictions such as diabetes, immunodeficiencies, compression traumas in bedridden people, skin grafts or third-degree burns. In this situation it is critical to constantly monitor the healing stages and the overall wound condition to allow for better targeted therapies and a faster patient recovery. At the moment, this operation is performed by removing the bandages and visually inspecting the wound, putting the patient at risk of infection and disturbance of the healing stages. Recently, new devices have been developed by our research group to address these issues by monitoring pH and moisture in wound fluid, as they are two important biomarkers related to the wound health status. In this contribution we present a novel textile chemical sensor exploiting an organic electrochemical transistor (OECT) configuration based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for uric acid (UA) selective monitoring in wound exudate. The combination of special medical-grade textile materials provides a passive sampling system which enables the continuous, real-time and non-invasive analysis of wound fluid to monitor the health status of wounds, as UA concentration is a relevant biomarker associated with infections or necrotization processes in human tissues. The sensors are realized by screen-printing a conductive ink based on PEDOT:PSS on medical gauzes, while the appropriate electrical connections are made by sewing conductive textile threads. UA determinations were conducted by means of potentiostatic electrochemical techniques both in phosphate buffers solutions (PBS) and synthetic wound exudate (SWE) while operating in flow conditions to simulate wound fluid delivery using an HPLC pump at a flow rate of 0.05 mL/min. The sensors here developed proved capable of responding reversibly to variations of UA concentration in the biological range of interest for wound exudate (220 - 750 μM), displaying a normalized current response (NCR) equal to a 47% signal variation per 10-fold increase in UA concentration (R2 = 0.98). The values obtained in PBS and SWE were found to be statistically comparable, as confirmed by a t-test (P = 0.95)
On the Quest for Oxygen Evolution Reaction Catalysts Based on Layered Double Hydroxides: An Electrochemical and Chemometric Combined Approach
Full text linkThe oxygen evolution reaction (OER) is a crucial process in various energy conversion and storage technologies, such as water electrolysis. Developing efficient and cost-effective electrocatalysts is essential to achieve the com-mercialization of devices for the transition toward sustainable energy solu-tions. Herein, ternary layer double hydroxides (LDHs) are synthesized and characterized as electrocatalysts for OER using a potentiodynamic electro-chemical deposition method on Grafoil. A chemometric approach based onexperimental design is employed to rationalize the effort in the investigation ofthe LDHs which are based on Ni, Co, and Fe. The deposited films are char-acterized using cyclic voltammetry and X-ray diffraction to determine peakcurrents and potentials, and crystal size. Furthermore, the electrocatalyst performances are assessed by linear sweep voltammetry in 1M KOH fromwhich the Tafel slope and onset potential are calculated. The obtained data areused to derive models describing the material properties and electrocatalyst performance as a function of the electrolyte composition used during the LDHs electrodeposition. This study provides valuable insights into the relationship between the electrocatalyst composition and its OER activity, enabling the design of more efficient and sustainable electrochemical systems for energy applications
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