Screen-printed electrodes with electropolymerized Meldola Blue as versatile detectors in biosensors (original) (raw)
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Electroanalysis, 2009
The redox mediator Meldola blue (MB) was entrapped into two polymers, poly-1,2-diaminobenzene (p-DAB) and poly-3,4-ethylenedioxythiophene (p-EDOT) by potential cycling and films were applied to NADH oxidation with subsequent glutamate detection using immobilized glutamate dehydrogenase. Both polymer films were tested for electrocatalysis of NADH using amperometry at E app ¼ 0.1 V vs. Ag/AgCl and similar response characteristics were obtained with sensitivity values of 6.1 nA mM À1 , linear range up to 0.5 mM (R 2 ¼ 0.9972) and LOD of 50 mM. Subsequent amperometric determination of glutamate resulted in sensitivity 0.7 nA mM À1 , linearity 0-100 mM and detection limit of 2 mM glutamate.
Talanta, 2003
Three strategies have been compared to produce screen-printed amperometric detectors for NADH: mixing Meldola Blue (MB) in the screen-printing ink, incorporation of MB Á/Reinecke salt (MBRS) in the graphite ink and electrodeposition of films of MB-derived polymer (poly (MB)) on electrode surface. Following modification of graphite electrodes the mediators displayed values of the formal potential E 8? from (/0.129 to (/0.160 V vs. Ag/AgCl and pK a s of 5.09 Á/6.02. A second redox couple with E 8?0/(/0.450 V vs. Ag/AgCl was observed in cyclic voltammetry experiments with poly (MB) sensors or with old electrodes obtained according to the other two strategies. Electropolymerisation of MB allowed to achieve the best operational stability and best detection limit, 2 )/10 (6 M, for amperometric detection of NADH, while the most extended linear range, 1 )/10 (5 Á/7.5)/10 (4 M, corresponds to sensors with MBRS. MB and MBRS electrodes were compared with a similar NADH detector produced by Gwent Electronic Materials, England. Several characteristics of the modified-electrodes induced by the fabrication by screenprinting were also highlighted. #
Polyphenol oxidase-based electrochemical biosensors: A review
Analytica Chimica Acta, 2020
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Sensor Letters, 2011
The electropolymerization of methylene blue (MB) from the phenothiazine group on screen printed carbon paste electrode (SPCE) has been successfully studied using repeated potential cycling. The characteristics of the modified electrodes were influenced by several experimental conditions such as MB concentration, scan rate, scanning range and number of cyclic scans. The catalytic properties of the modified electrodes allowed NADH oxidation at a lower potential of +0 08 V versus Ag/AgCl. The resulting modified electrodes also exhibited a linear response towards NADH in the concentration range of 10 to 100 M with the detection limit of 10 M.
Analytical and Bioanalytical Chemistry, 2015
This study compares the behaviour of direct and mediated electrochemistry of horseradish peroxidase (HRP) immobilised on screen-printed carbon electrodes (SPCEs), screen-printed carbon electrodes modified with carboxylfunctionalised multi-wall carbon nanotubes (MWCNT-SPCEs) and screen-printed carbon electrodes modified with carboxyl-functionalised single-wall carbon nanotubes (SWCNT-SPCEs). The techniques of cyclic voltammetry and amperometry in the flow mode were used to characterise the properties of the HRP immobilised on screen-printed electrodes. From measurements of the mediated and mediatorless currents of hydrogen peroxide reduction at the HRP-modified electrodes, it was concluded that the fraction of enzyme molecules in direct electron transfer (DET) contact with the electrode varies substantially for the different electrodes. It was observed that the screen-printed carbon electrodes modified with carbon nanotubes (MWCNT-SPCEs and SWCNT-SPCEs) demonstrated a substantially higher percentage (≈100 %) of HRP molecules in DET contact than the screen-printed carbon electrodes (≈60 %). The HRPmodified electrodes were used for determination of hydrogen peroxide in mediatorless mode. The SWCNT-SPCE gave the lowest detection limit (0.40±0.09 μM) followed by MWCNT-SPCE (0.48±0.07 μM) and SPCE (0.98±0.2 μM). These modified electrodes were additionally developed for amperometric determination of phenolic compounds. It was found that the SWCNT-SPCE gave a detection limit for catechol of 110.2±3.6 nM, dopamine of 640.2±9.2 nM, octopamine of 3341±15 nM, pyrogallol of 50.10±2.9 nM and 3,4-dihydroxy-L-phenylalanine of 980.7±8.7 nM using 50 μM H 2 O 2 in the flow carrier.
Analytica Chimica Acta, 1996
A new composite membrane of poly(viny1 alcohol) (PVA) and regenerated silk fibroin (RSF) was successfully employed to immobilize horseradish peroxidase (HRP) and infrared (IR) was used to get insight in the structure of the composite membrane. An amperometric HRP-based sensor highly sensitive to hydrogen peroxide was fabricated, which was based on Meldola Blue as a mediator to facilitate efficient electron transfer between immobilized HRP and a glassy carbon electrode. Performance and characteristics of the sensor were evaluated with respect to response time, detection limit, selectivity, operating and storage stability, and dependence on temperature, pH, applied potential and mediator concentration. The sensor displayed high sensitivity to hydrogen peroxide with low detection of limit of 0.1 PM.
Analytica Chimica Acta, 1995
Prussian blue has been formed by cyclic voltammetry onto the basal pyrolytic graphite surface to prepare a chemically modified electrode which provides excellent electrocatalysis for both oxidation and reduction of hydrogen peroxide. It is found for the first time that glucose oxidase or D-amino oxidase can be incorporated into a Prussian blue film during its electrochemical growth process. Two amperometric biosensors were fabricated by electrochemical codeposition, and the resulting sensors were protected by coverage with a thin film of Nafion. The influence of various experimental conditions was examined for optimum analytical performance. The glucose sensor responds rapidly to substrates with a detection limit of 2 X 10m6 M and a linear concentration range of 0.01-3 mM. There was no interference from 2 mM ascorbic acid or uric acid. Another (o-amino acid) sensor gave a detection limit of 3 X lo-' M D-shine, injected with a linear concentration range of 7.0 X lo-'-l.4 X lo-' M. Glucose and n-amino acid sensors remain relatively stable for 20 and 15 days, respectively. There is no obvious interference from anion electroactive species due to a low operating potential and excellent pemrselectivity of Nafion.
Electroanalysis, 2003
Exfoliated graphite (EG) particles covalently functionalized with phenoxazine-based molecules have been used to prepare bulk-modified electrodes. The electrodes are of two types: 1) binder-less covalently modified EG pellets and 2) sol-gel derived composites of silicate and modified EG particles. The covalent modification is confirmed by infrared spectroscopy. The electrochemistry of attached molecules has been carried out to decipher the catalytic activity of immobilized phenoxazines towards NADH oxidation. Fast response time of about 4 ± 6 seconds and a low detection limit of 20 mM have been achieved using these electrodes. The sensor is found to yield a linear range of current response versus concentration between 0.02 and 1 mM of NADH. Biosensing in presence of alcohol dehydrogenase enzyme and NAD shows a linear response between 1 and 13 mM and the response time for alcohol sensing is found to be 20 ± 30 s. These electrodes are found to be very stable during operation and can be stored without any deterioration over a period of several months.
Anais da Academia Brasileira de Ciências, 2017
A new modified electrode for indirect sensing of OH • and radical scavengers was described. The electrochemical polymerization of methylene blue in aqueous solutions and the properties of the resulting films on a glassy carbon electrode were carried out using cyclic voltammetry. A surface coverage of 1.11 × 10 9 mol cm 2 was obtained, revealing a complete surface coverage of the polymeric film on the electrode surface. OH • was able to destroy the poly(methylene blue) film by exposure to a Fenton solution. The loss of the electrochemical signal of the residual polymeric film attached to the electrode surface was related to the extent of its dissolution. The applicability of the sensor was demonstrated by evaluating the OH radical scavenging effect on different concentrations of ascorbic acid. The obtained radical scavenging capacity were 31.4%, 55.7%, 98.9% and 65.7% for the ascorbic acid concentrations of 5, 10, 30 and 50 mM, respectively.
Sensors and Actuators B: Chemical, 1999
The present investigation of a novel electrochemical transducer is defined by the requirements of the one of the most significant fields of modern analytical biotechnology, i.e., electrochemical biosensors. Prussian Blue, which has been deposited on the surface of glassy carbon electrode under certain conditions, was found to be a selective electrocatalyst for H O reduction in the presence of O . In its 2 2 2 Ž . reduced form Prussian White the inorganic polycrystal is known to be partially soluble in aqueous solution. To stabilize the electrocatalyst at cathodic potentials and preventing loss from the electrode surface, an independent investigation was performed. As a result, a completely stable electrocatalyst was achieved. The kinetics of H O reduction onto the surface of Prussian Blue modified 2 2 electrodes was investigated. Due to the high catalytic activity and selectivity which were comparative with biocatalysis, the specially deposited Prussian Blue was denoted as 'artificial peroxidase'. The biosensors were made by enzyme immobilization on the top of the Prussian Blue modified electrodes. The electrochemical transducer and biosensors were suitable for detection of low analyte levels and were practically independent of potentially interfering reductants. q 1999 Elsevier Science S.A. All rights reserved.