Strategies for developing NADH detectors based on Meldola Blue and screen-printed electrodes: a comparative study (original) (raw)
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Sensors and Actuators B-chemical, 2008
Amperometric biosensors based on NADHox/FMN and Prussian blue modified screen-printed electrodes (SPE) have been developed in order to improve the NADH detection. The catalytic effect, the sensitivity and the stability of PB-modified SPEs were studied for different pH buffer solutions and different voltage range, by cyclic voltammetry and amperometric measurements. NADH oxidase was immobilised on Prussian blue modified SPEs by entrapment in sol-gel, PVA-AWP polymer matrices or using glutaraldehyde. The amperometric detection of NADH was performed at +0.25 V versus Ag/AgCl. FMN was added in reaction medium or either immobilised. Better results were obtained when FMN was entrapped with NADHox in the biocatalytic layer using sol-gel matrix. The sensitivity was 4.57 mA M −1 cm −2 (R.S.D. = 9.2%, n = 4), the linear range up to 1.61 mM and the detection limits about 1.17 M. These biosensors present a good long term and operational stability, the response decreases from 3.4% after 2 days, to 50% of the analytical signal after 6 months.
Sensors and Actuators B: Chemical, 2014
A screen-printed electrode (SPE) modified with poly(allylamine hydrochloride) (PAH) for electrochemical detection of NADH is described. FT-IR spectrum confirms the presence of a positively charged PAH SPE that was exploited to accumulate the NADH on the electrode surface for a faster electrochemical detection of this analyte. A wide response range was achieved in amperometry, at an applied potential of +0.6 V, from 0.01 to 5 mM, with a detection limit of 0.22 M. Differential pulse voltammetry allowed selective detection of NADH in presence of ascorbic acid. This approach provides a simple and effective way to detect low amounts of NADH with potential application in dehydrogenase-based biosensors.
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.
International Journal of Environmental Analytical Chemistry, 2019
A new amperometric NADH sensor was developed based on screen-printed electrode (SPCE) modified with reduced graphene oxide (RGO), polyneutral red (PNR) and gold nanoparticles (AuNP). Electrochemical behaviour of NADH on SPCE/RGO/PNR/AuNP was investigated. The prepared sensor showed a high electrocatalytic effect on the oxidation of NADH. The sensor response for NADH was investigated as a function of pH and working potential. Optimum values of these parameters in the NADH determination were found as 7.0 for pH and +0.15 V for working potential. Sensitivity, linear range, limit of detection and limit of quantification of the sensor were found to be 8.72 μAmM −1 , 5 to 3170 μM, 0.384 μM and 1.18 μM, respectively. The relative standard deviation (RSD) was calculated to be 1.93% (for n = 10). The operational stability studies have shown that the initial amperometric response of sensor to NADH decreased by 56.15% at the 60th day. Storage life studies have shown that the sensitivity of the biosensor decreased by 48.72% at the end of 12 weeks. The developed sensor has been tested for NADH determination in the human serum sample. The developed NADH sensor is promising to be used for NADH analysis in human serum samples as simple, practical and disposable device without requiring laborious sample pre-treatment producers.
Analytical Sciences, 1993
Poly(thionine)-modified electrodes have been prepared using basal-plane pyrolytic graphite, glassy carbon and In-Sn oxide conducting glass as electrode substrates by an electrooxidative polymerization of thionine in both aqueous and acetonitrile media. It was found that the prepared films, the surface concentration of which can be controlled over the range of ca. 10-10-10-g mol cm 2 by appropriately choosing the electropolymerization conditions (e.g., solvent, concentration of thionine and electrolysis time), are electroactive (the formal potential is ca. 0.0 V vs. Ag/AgCI at pH 7.0) and chemically stable. The modified electrodes exhibited excellent electrocatalysis for NADH oxidation in neutral aqueous solutions, with an activation overpotential which is ca. 400 mV lower than that of a bare electrode. Further, the modified glassy carbon electrode was found to be promising as an amperometric detector for the flow-injection analysis of NADH, typically with a dynamic range of 5 µM-1 mM.
Biosensors and Bioelectronics, 1993
Amperometric biosensors based on redox polymer-mediated electron transfer from NADH to carbon paste electrodes, regenerating the NAD+ needed for the dehydrogenase-catalysed reaction, are described. These sensors, operating around 0 mV vs SCE, can drive an unfavourable equilibrium of a dehydrogenase-catalysed reaction to the product side, and are reagentless in that NAD+ need not be added to the analyte solution. By covering the sensor with an additional polymer, protection of the electrode surface, inclusion of water soluble components, exclusion of interferents and a diffusion controlled linear response current can be obtained.
Talanta, 2005
The carbon ceramic electrode prepared with sol–gel technique is modified by a thin film of chlorogenic acid (CGA). By immersing the carbon ceramic electrode in aqueous solution of chlorogenic acid at less than 2 s a thin film of chlorogenic acid adsorbed strongly and irreversibly on the surface of electrode. The cyclic voltammetry of the resulting modified CCE prepared at optimum conditions shows a well-defined stable reversible redox couple due to hydroquinone/quinone system in both acidic and basic solutions. The modified electrode showed excellent electrocatalytic activity toward NADH oxidation and it also showed a high analytical performance for amperometric detection of NADH. The catalytic rate constant of the modified carbon ceramic electrode for the oxidation of NADH is determined by cyclic voltammetry measurement. Under the optimised conditions the calibration curve is linear in the concentration range 1–120 μm. The detection limit (S/N = 3) and sensitivity are 0.2 μM and 25 nA μM−1.The results of six successive measurement-regeneration cycles show relative standard deviations of 2.5% for electrolyte solution containing 1 mM NADH, indicating that the electrode renewal gives a good reproducible and antifouling surface. The advantages of this amperometric detector are: high sensitivity, excellent catalytic activity, short response time t < 2 s, remarkable long-term stability, simplicity of preparation at short time and good reproducibility.
Biosensors and Bioelectronics, 2007
Modified screen-printed electrodes for amperometric detection of H 2 O 2 and nicotinamide adenine dinucleotide (NADH) at low applied potential are presented in this paper. The sensors are obtained by modifying the working electrode surface with Prussian Blue, a well known electrochemical mediator for H 2 O 2 reduction. The coupling of this sensor with phenazine methosulfate (PMS) in the working solution gives the possibility of measuring both NAD(P)H and H 2 O 2 . PMS reacts with NADH producing PMSH, which in the presence of oxygen, gives an equimolar amount of H 2 O 2 . This allows the measurement of both analytes with similar sensitivity (357 mA mol −1 L cm −2 for H 2 O 2 and 336 mA mol −1 L cm −2 for NADH) and LOD (5 × 10 −7 mol L −1 for H 2 O 2 and NADH) and opens the possibility of a whole series of biosensor applications.
Effect of surface-active agents on amperometric NADH measurement with chemically modified electrodes
Analytica Chimica Acta, 1995
A special electrochemical pretreatment was employed in the case of finely polished glassy carbon electrode surfaces to increase the adsorption of the redox mediator Meldola blue (7-dimethylamino-1,2-benzophenoxazine). The chemically modified glassy carbon electrode holding the adsorptive mediator layer was used to measure the NADH concentration amperometrically. The interfering effect of non-ionic surfactants was studied for NADH measurements using a rotating disc electrode technique and flow injection measurements. The glassy carbon electrode response was less affected and could be regenerated much more easily than the response of a similar spectrographic graphite based electrode, studied earlier. Surface active agents can influence the apparent coverage of the surface by the mediator.
Screen-printed electrodes with electropolymerized Meldola Blue as versatile detectors in biosensors
Biosensors & Bioelectronics, 2003
Electropolymerization of Meldola Blue was carried out by cyclic voltammetry in the range from (/0.6 to '/1.4 V vs. Ag/AgCl, thus defining a new immobilization procedure of the phenoxazine mediator on screen-printed graphite electrodes. Evidence of polymer formation was provided by electrochemical and Fourier transform infrared spectroscopy (FTIR) data. Following polymerization, Meldola Blue preserved the ability to catalyze NADH oxidation allowing to achieve a detection limit of 2.5 )/10 (6 mol l (1 and a sensitivity of 3713 mA l mol (1 in amperometric determinations at 0 V vs. Ag/AgCl. In addition, the polymeric mediator was found to facilitate the reduction of hydrogen peroxide in the absence of peroxidase. Typical calibration at (/0.1 V vs. Ag/AgCl shows a detection limit of 8.5 )/10 (5 mol l (1 , a sensitivity of 494 mA l mol (1 and a linear range from 2.5 )/10 (4 to 5 )/ 10 (3 mol l (1 hydrogen peroxide. #