Synthesis of robust electrochemical substrate and fabrication of immobilization free biosensors for rapid sensing of salicylate and β -hydroxybutyrate in whole blood (original) (raw)
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Electroanalysis, 2001
The electrochemical immobilization of salicylate hydroxylase (SH) within poly(amphiphilic pyrrole ammonium) films electrogenerated on carbon electrode is described. The amperometric determination of salicylate is carried out at 0.4 V (vs. Ag=AgCl) via the oxidation of the enzymically generated catechol. The detection limit and the sensitivity of the polypyrrole-SH electrode were 3610 À9 M and 1.7 A M À1 cm À2 , respectively. Moreover, the co-entrapment of SH and polyphenol oxidase (PPO) in such polypyrrole films provides a bienzyme electrode also for the determination of salicylate. Contrary to the monoenzyme electrode, the functioning principle of the bienzyme electrode is based on the reduction of o-quinone enzymically generated from catechol. Consequently, the amperometric detection of salicylate was performed at À0.2 V without interferences from easily oxidizable compounds. The calibration range for salicylate measurement and the biosensor sensitivity were 5610 À8 -3610 À6 M and 0.25 A M À1 cm À2 , respectively.
Biosensors and Bioelectronics, 2010
The use of an amperometric biosensor for rapid salicylate determination in blood is described. Photolitography was used to make gold electrodes on a polyester film. The plastic microcell was characterized using cyclic voltammetry to demonstrate the electrochemical performance of the system. The biosensor was constructed by immobilizing salicylate hydroxylase onto the working electrode of the plastic electrochemical microcell. The optimized working conditions were 0.1 mol L −1 phosphate buffer at pH 7.6 with 0.5 mmol L −1 of NADH and 300 mV vs. Au as the applied potential. The resulting biosensor exhibited a high sensitivity (97.4 nA/mmol L −1 salicylate) and an adequate linear response range (1.2 × 10 −4 to 1.0 × 10 −3 mol −1 ). The biosensor performance was verified by determining salicylate in spiked blood samples and the results were statistically equivalent to the values obtained from the standard Trinder spectrophotometric method, with a 95% confidence level. This study shows the potential development of a portable, inexpensive and disposable device for point-of-care monitoring.
Determination of salicylate in blood serum by flow injection with immobilized salicylate hydroxylase
Journal of AOAC International
A flow injection (FI) enzymatic system, based on the use of immobilized salicylate hydroxylase in glass beads, was developed for the determination of salicylate. Salicylate hydroxylase and nicotinamide adenine dinucleotide (NADH) are used to convert salicylate to catechol. The reaction of catechol with 4-aminophenol at high pH yields a colored product which is detected spectrophotometrically at 565 nm. Ten samples of human serum containing from 5.0 x 10(-4) to 5.0 x 10(-3) mol/L added salicylate were analyzed and the recovery was determined. Eight additional serum samples containing salicylate were analyzed by the Trinder test and the proposed method. The results obtained with the 2 methods showed good agreement by the statistical Student's t-test. The relative precision of the method is about 3.4% (RSD of the mean recovery). Considering the lowest concentration analyzed, the quantitative limit of detection is about 0.2 x 10(-5) mol/L (3 x SD). The volume of the sample used was ...
Biosensors and Bioelectronics, 2016
Volatile organic compounds have been recognized as important marker chemicals to detect plant diseases caused by pathogens. Methyl salicylate has been identified as one of the most important volatile organic compounds released by plants during a biotic stress event such as fungal pathogen infection. Advanced detection of these marker chemicals could help in early identification of plant diseases and has huge significance for agricultural industry. This work describes the development of a novel bi-enzyme based electrochemical biosensor consisting of salicylate hydroxylase and tyrosinase enzymes immobilized on carbon nanotube modified electrodes. The amperometric detection using the bi-enzyme platform was realized through a series of cascade reactions that terminate in an electrochemical reduction reaction. Electrochemical measurements revealed that the sensitivity of the bi-enzyme sensor was 30.6 ± 2.7 µA•cm-2 •µM-1 respectively and the limit of detection and limit of quantification were 13 nM (1.80 ppb) and 39 nM (5.39 ppb) respectively. Interference studies showed no significant interference from the other common plant volatile compounds. Synthetic analyte studies revealed that the bi-enzyme based biosensor can be used to reliably detect methyl salicylate released by unhealthy plants.
Analytical Characteristics of Electrochemical Biosensors
Portugaliae Electrochimica Acta, 2009
The goal of this work is the evaluation of the analytical characteristics of the determinations performed using glucose oxidase and acetylcholinesterase based electrochemical sensors, developed applying original or optimized conventional methods of enzyme immobilization. It was found that the sensitivity of glucose determination, for example, varies from 0.048 to 3.36 mA L mol -1 cm -2 and the response time of the glucose oxidase based sensors -from 5 to 30 s, according to the method of the bioreceptor immobilization. The sensitivity of the analysis is affected from the activity of the immobilized biocomponent, from the composition of the solution (concentration of the substrate, of the mediator and of the inhibitor), and from the experimental conditions (pH, temperature, agitation), as well as from the kinetic parameters of the studied process. It was found that the immobilized glucose oxidase conserves its substrate specificity in the presence of a number of glucides (galactose, maltose, fructose, and saccharose) in 100 fold higher concentrations. The selectivity of glucose analysis is ensured applying a suitable potential. Interferences free glucose amperometric determination was performed at 0.00 V/SCE, in the presence of ascorbates and urates. The electrochemical quantification of enzyme inhibitors allows reaching particularly low limits of detection (
Recent Developments, Characteristics, and Potential Applications of Electrochemical Biosensors
Analytical Sciences, 2004
The modern concept of biosensors represents a rapidly expanding field of instruments to determine the concentration of substances and other parameters of biological interest since the invention of Clark and Lyons in 1962, for example, created the availability of a rapid, accurate, and simple biosensor for glucose. Biological sensors are analytical devices that detect biochemical and physiological changes. Transducers are essential to convert the particular biological and chemical (biochemical) change into electrical data which can identify different biochemical components of a complex compound to isolate the desired biochemical compounds, for instance, carbon monoxide and sulfur dioxide that contribute to the air pollution. Historically, Clark and Lyons first demonstrated the modern concept of biosensors, in which an enzyme was integrated into an electrode to form a biosensor. The developments of such simple detection tools and similar techniques have made considerable progress since then. Early techniques of biosensors in the analysis of chemical and biological species involved reactions that took place in a solution in addition to catalysts and samples. In recent years, however, the biosensor techniques have provided alternative systems that allowed the reactions without adding reagents to take place at a surface of an electrode. Since the reagents have been already immobilized in the systems, the biological and chemical sensor has performed the task of identifying composition of species with minimum human intervention. The recent improvement of biosensor techniques has continued to depend on and learn from the inefficiency of the early techniques. 1-6 The most common immobilization techniques are physical 1113
Determination of salicylate in beverages and cosmetics by use of an amperometric biosensor
Analytical and bioanalytical chemistry, 1996
A fast and selective enzymatic method for the determination of salicylate in beverages and cosmetics has been developed. The enzyme salicylate hydroxylase was immobilised covalently onto a glassy carbon working electrode of a wall-jet cell coupled with a flow-injection analysis system. The salicylate is enzymatically converted to catechol, which can be detected amperometrically on the glassy carbon electrode at +0.45 V. The response of the biosensor is linearly proportional to the concentration of salicylate between 725 nmol/l and 700 micromol/l. A high sample throughput (60 h(-1)) is possible, and the biosensor is stable for more than three months. Sample pretreatment for beverages and hair lotions is easy and fast. For creams, an extraction of salicylate is necessary. Relative standard deviations are less than 5.5% and the recoveries are between 95 and 105%.
2015
We have mounted 5 different biocatalysts on a sensor platform to examine the performance of this electrochemical sensing system for the detection of different biomolecules/metabolites and environmental important molecules, with such we also compared how this sensing system fares with literature results of similar measurements. The biocatalysts are LDH (lactate dehydrogenase), GDH (glutamate dehydrogenase), human IgG (human immunoglobulin G), Hb (hemoglobin), and PSA (prostatespecific antigen). The sensor platform constitutes of a layer of biocomposite mounted on different electrodes made out of Au, Ag, Pt, and glass carbon; the biocomposite is fabricated with polymers and sol-gel Au nanoparticles with or without an extra layer of biomolecules. The targeting species for measurements include NH4, NO3, CN, H2O2 and the biomolecules specific to the biomolecules/antigens coated on the surface of the biocomposites. In this report, we will provide a comprehensive analysis of this sensing s...
Biosensor for rapid determination of 3-hydroxybutyrate using bienzyme system
Biosensors and Bioelectronics, 2006
A bienzyme-based Clark electrode was developed for the determination of 3-hydroxybutyrate. This sensor is based on the specific dehydrogenation by 3-hydroxybutyrate dehydrogenase (HBDH, E.C. 1.1.1.30) in combination with salicylate hydroxylase (SHL E.C. 1.14.13.1). The enzymes were entrapped by a poly(carbamoyl) sulfonate (PCS) hydrogel on a Teflon membrane. The principle of the determination scheme is as follows: the specific detecting enzyme, HBDH, catalyses the specific dehydrogenation of 3-hydroxybutyrate consuming NAD + . The products, NADH, initiate the irreversible decarboxylation and the hydroxylation of salicylate by SHL in the presence of oxygen. SHL forces the equilibrium of dehydrogenation of 3-hydroxybutyrate by HBDH to the product side by consuming NADH. Dissolved oxygen acts as an essential material for SHL during its enzymatic reactions. This results in a detectable signal due to the SHL-enzymatic consumptions of dissolved oxygen in the measurement of 3-hydroxybutyrate. Interferences from different amino acids and electroactive substances were found to be minimal due to the specificity of HBDH and the application of a Teflon membrane. The sensor has a fast response (2 s) and short recovery time (2 min) with a linear range between 8 and 800 M 3-hydroxybutyrate and a detection limit of 3.9 M. A good agreement (R 2 = 0.9925) with theoretical calculation was obtained in spiked serum sample measurements.