A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles (sm-Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition w...A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles (sm-Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition was optimized for obtaining uniformly distributed sub-micrometer sized Au array on the electrode surface. The hy-drogen peroxide sensor was fabricated by adsorbing phenothiazine methylene blue (MB) molecules on the surface of sm-Au and covering a cross-linked horseradish peroxidase (HRP) layer, labeled as HRP/MB/sm-Au/GCE. The characteristics of this biosensor were evaluated with respect to applied potential and pH. The amperometric re-sponse of the sensor was linear to the H2O2 concentration over a wide range of 9.9×10-61.11×10-2 mol/L. A detection limit (s/n=3) of 3.0×10-6 mol/L H2O2 was estimated for a sampled chronoamperometric detection at 1.5 min after potential step of 200 to -400 mV vs. SCE. The immobilized MB molecules shuttled electrons at a=0.77 and an apparent electron transfer rate constant of 0'sk=0.053 s-1. Interference of ascorbic acid, dopamine and uric acid was investigated. This sensor has very good stability and reproducibility for long-term use.展开更多
Response of biosensor prepared with the thermostable bacterial LDH enzyme was analyzed in the presence of mercury and nickel.For electrode preparation,the enzyme was purified and immobilized on a gold sheet coated by ...Response of biosensor prepared with the thermostable bacterial LDH enzyme was analyzed in the presence of mercury and nickel.For electrode preparation,the enzyme was purified and immobilized on a gold sheet coated by PGA-pyrrole polymeric material.The working electrode was tested at increasing concentration of lactate in the presence of two different concentrations of mercury and nickel.Current response of biosensor decreased from 0.32 μA to 0.09 μA and 4.13 μA to 2.63 μA when 25×10-7 mmol/L mercury and 17×10-5 mmol/L nickel were included in the working solution,respectively.Sensitivity of the electrode decreased from 0.010 2 μA/(mmol·L-1) to 0.0043 μA/(mmol·L-1) in the presence of 25×10-7 mmol/L mercury.On the other hand,the presence of nickel did not result in a decrease in electrode sensitivity.The results pointed out that the prepared biosensor is useful to detect mercury in a sample containing both mercury and nickel together.展开更多
Homotopy analysis method (HAM) is employed to investigate amperometric biosensor at mixed enzyme kinetics and diffusion limitation. Mathematical modeling of the problem is developed utilizing non-Michaelis-Menten kine...Homotopy analysis method (HAM) is employed to investigate amperometric biosensor at mixed enzyme kinetics and diffusion limitation. Mathematical modeling of the problem is developed utilizing non-Michaelis-Menten kinetics of the enzymatic reaction. Different results of the problem are obtained for different values of the dimensionless parameters. Accuracy of the obtained results is verified by comparing them with the available actual and simulated ones. It is concluded that the obtained solution can be considered as a promising one to investigate different aspects of the phenomena.展开更多
The third generation amperometric biosensor for the determination of hydrogen peroxide (H2O2) has been described. For the fabrication of biosensor, o-aminobenzoic acid (oABA) was first electropolymerized on the su...The third generation amperometric biosensor for the determination of hydrogen peroxide (H2O2) has been described. For the fabrication of biosensor, o-aminobenzoic acid (oABA) was first electropolymerized on the surface of platinum (Pt) electrode as an electrostatic repulsion layer to reject interferences. Horseradish peroxidase (HRP) absorbed by nano-scaled particulate gold (nano-Au) was immobilized on the electrode modified with polymerized o-aminobenzoic acid (poABA) with L-cysteine as a linker to prepare a biosensor for the detection of H2O2. Amperometric detection of H2O2 was realized at a potential of +20 mV versus SCE. The resulting biosensor exhibited fast response, excellent reproducibility and sensibility, expanded linear range and low interferences. Temperature and pH dependence and stability of the sensor were investigated. The optimal sensor gave a linear response in the range of 2.99×10^-6 to 3.55×10^-3 mol·L^-1 to H2O2 with a sensibility of 0.0177 A·L^-1·mol^-1 and a detection limit (S/N = 3) of 4.3×10^-7 mol·L^-1. The biosensor demonstrated a 95% response within less than 10 s.展开更多
The practical use of non-conducting poly(o-aminophenol) (POAP) films in the field of the bioelectrochemistry is discussed in this paper. Particular emphasis is given to the effects of applied potential, solution pH an...The practical use of non-conducting poly(o-aminophenol) (POAP) films in the field of the bioelectrochemistry is discussed in this paper. Particular emphasis is given to the effects of applied potential, solution pH and interferents on the response current of biosensors based on POAP.展开更多
A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods tha...A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods that it requires low potential to generate electrons from H2O2, which does not allow ionization of serum substances. The optimum working conditions of amperometric determination were pH 6.8, 25?C and 30 s. The current measured was in proportion to cholesterol concentration ranging from 1.29×10-3 to 10.33×10-3 M. Minimum detection limit of the method was 0.09 ×10-3 M. Mean analytical recovery of added cholesterol (100 mg/dl and 200 mg/dl) in serum was 85.0% & 90.0% respectively. Within batch and between batch coefficients of variations were 1.59% & 4.15% respectively. A good correlation (r = 0.99) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. No interference by metabolites was observed in the method. The enzyme electrode was reused 200 times over a period of 25 days, when stored at 4?展开更多
An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagen...An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagent cast and dried on the electrode.The biosensor responses to AST by detecting hydrogen peroxide were produced by enzymical reaction at-0.1 V with a response time of 120 seconds.The electrode gave a detection limit of 32.5 U/L with a linear concentration range of 32.5 U/L~2000 U/L in serum.Due to more sensitive and lower detection limit,the biosensor is expected mainly to be used for physiological identification and physical performance of athletes in the future.Extended application will also affect the practice of clinical medicine for the diagnosis of heart and liver disease.展开更多
A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrod...A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrodes.The biosensor consisted of an Ag/AgCl reference electrode and a graphite working electrode.The mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on electrodes.The detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as substrate.The biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE activity.The 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode surface.The biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L KCl.We obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 ppm.The amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).展开更多
In this article, Discrete Homotopy Analysis Method (DHAM), as a new numerical method, is employed to investigate amperometric biosensor at mixed enzyme kinetics and diffusion limitation. Mathematical modeling of the p...In this article, Discrete Homotopy Analysis Method (DHAM), as a new numerical method, is employed to investigate amperometric biosensor at mixed enzyme kinetics and diffusion limitation. Mathematical modeling of the problem is developed utilizing non-Michaelis-Menten kinetics of the enzymatic reaction. Different results are obtained for different values of the dimensionless parameters described in the paper. The presented solution is then compared with the available actual and simulated results.展开更多
文摘A new type of hydrogen peroxide amperometric biosensor was fabricated based on electrochemically deposited sub-micrometer Au particles (sm-Au) on a glassy carbon electrode (GCE). Electrochemical deposition condition was optimized for obtaining uniformly distributed sub-micrometer sized Au array on the electrode surface. The hy-drogen peroxide sensor was fabricated by adsorbing phenothiazine methylene blue (MB) molecules on the surface of sm-Au and covering a cross-linked horseradish peroxidase (HRP) layer, labeled as HRP/MB/sm-Au/GCE. The characteristics of this biosensor were evaluated with respect to applied potential and pH. The amperometric re-sponse of the sensor was linear to the H2O2 concentration over a wide range of 9.9×10-61.11×10-2 mol/L. A detection limit (s/n=3) of 3.0×10-6 mol/L H2O2 was estimated for a sampled chronoamperometric detection at 1.5 min after potential step of 200 to -400 mV vs. SCE. The immobilized MB molecules shuttled electrons at a=0.77 and an apparent electron transfer rate constant of 0'sk=0.053 s-1. Interference of ascorbic acid, dopamine and uric acid was investigated. This sensor has very good stability and reproducibility for long-term use.
文摘Response of biosensor prepared with the thermostable bacterial LDH enzyme was analyzed in the presence of mercury and nickel.For electrode preparation,the enzyme was purified and immobilized on a gold sheet coated by PGA-pyrrole polymeric material.The working electrode was tested at increasing concentration of lactate in the presence of two different concentrations of mercury and nickel.Current response of biosensor decreased from 0.32 μA to 0.09 μA and 4.13 μA to 2.63 μA when 25×10-7 mmol/L mercury and 17×10-5 mmol/L nickel were included in the working solution,respectively.Sensitivity of the electrode decreased from 0.010 2 μA/(mmol·L-1) to 0.0043 μA/(mmol·L-1) in the presence of 25×10-7 mmol/L mercury.On the other hand,the presence of nickel did not result in a decrease in electrode sensitivity.The results pointed out that the prepared biosensor is useful to detect mercury in a sample containing both mercury and nickel together.
文摘Homotopy analysis method (HAM) is employed to investigate amperometric biosensor at mixed enzyme kinetics and diffusion limitation. Mathematical modeling of the problem is developed utilizing non-Michaelis-Menten kinetics of the enzymatic reaction. Different results of the problem are obtained for different values of the dimensionless parameters. Accuracy of the obtained results is verified by comparing them with the available actual and simulated ones. It is concluded that the obtained solution can be considered as a promising one to investigate different aspects of the phenomena.
基金Project supported by the National Natural Science Foundation of China (No. 29705001), the Chinese Education Ministry Foundation for Excellent Young Teachers (No. 2002-40), the Natural Science Foundation of Chongqing City, China (Nos. CSTC-2004BB4149 and 2005BB4100) and High Technology Project of Southwest University (No. XSGX02).
文摘The third generation amperometric biosensor for the determination of hydrogen peroxide (H2O2) has been described. For the fabrication of biosensor, o-aminobenzoic acid (oABA) was first electropolymerized on the surface of platinum (Pt) electrode as an electrostatic repulsion layer to reject interferences. Horseradish peroxidase (HRP) absorbed by nano-scaled particulate gold (nano-Au) was immobilized on the electrode modified with polymerized o-aminobenzoic acid (poABA) with L-cysteine as a linker to prepare a biosensor for the detection of H2O2. Amperometric detection of H2O2 was realized at a potential of +20 mV versus SCE. The resulting biosensor exhibited fast response, excellent reproducibility and sensibility, expanded linear range and low interferences. Temperature and pH dependence and stability of the sensor were investigated. The optimal sensor gave a linear response in the range of 2.99×10^-6 to 3.55×10^-3 mol·L^-1 to H2O2 with a sensibility of 0.0177 A·L^-1·mol^-1 and a detection limit (S/N = 3) of 4.3×10^-7 mol·L^-1. The biosensor demonstrated a 95% response within less than 10 s.
文摘The practical use of non-conducting poly(o-aminophenol) (POAP) films in the field of the bioelectrochemistry is discussed in this paper. Particular emphasis is given to the effects of applied potential, solution pH and interferents on the response current of biosensors based on POAP.
文摘A cholesterol oxidase from Streptomycin sp. was immobilized onto pencil graphite rod and employed for amperometric determination of serum cholesterol. The method has the advantage over earlier amperometric methods that it requires low potential to generate electrons from H2O2, which does not allow ionization of serum substances. The optimum working conditions of amperometric determination were pH 6.8, 25?C and 30 s. The current measured was in proportion to cholesterol concentration ranging from 1.29×10-3 to 10.33×10-3 M. Minimum detection limit of the method was 0.09 ×10-3 M. Mean analytical recovery of added cholesterol (100 mg/dl and 200 mg/dl) in serum was 85.0% & 90.0% respectively. Within batch and between batch coefficients of variations were 1.59% & 4.15% respectively. A good correlation (r = 0.99) was obtained between serum cholesterol values by standard enzymic colorimetric method and the present method. No interference by metabolites was observed in the method. The enzyme electrode was reused 200 times over a period of 25 days, when stored at 4?
文摘An enzyme biosensor for amperometric measurement of aspartate aminotransferase has been developed.The working electrode was modified with a thin-film of redox polymer,then glutamate oxidase,with the immobilized reagent cast and dried on the electrode.The biosensor responses to AST by detecting hydrogen peroxide were produced by enzymical reaction at-0.1 V with a response time of 120 seconds.The electrode gave a detection limit of 32.5 U/L with a linear concentration range of 32.5 U/L~2000 U/L in serum.Due to more sensitive and lower detection limit,the biosensor is expected mainly to be used for physiological identification and physical performance of athletes in the future.Extended application will also affect the practice of clinical medicine for the diagnosis of heart and liver disease.
文摘A rapid,simple,disposable and inexpensive acetylcholinesterase (ACHE) amperometric biosensor for the detection of organophosphorus pesticides was developed by simple adsorption of the enzyme on screen-printed electrodes.The biosensor consisted of an Ag/AgCl reference electrode and a graphite working electrode.The mixture of graphite and the 7,7,8,8-tetracyanoquinodimethane (TCNQ) was printed on electrodes.The detection of organophosphorus pesticides was done with acetylthiocholine chloride (ATCh) as substrate.The biosensor was used to detect the inhibitory effect of organophosphorus pesticides on AChE activity.The 1μl of enzyme solution containing 0.1 U AChE and 1% bovine serum albumin (BSA) were simply dropped on the working electrode surface.The biosensor operated at a potential of 300 mV vs. Ag/AgCl in a pH 7.2 0.1 mol/L phosphate buffer and 0.1 mol/L KCl.We obtained a calibration plot of the percentage inhibition versus the logarithm of parathion methyl concentration following an incubation time of 10 mix in parathion methyl solution. The lowest detectable amount of parathion methyl was 0.026 ppm.The amperometric biosensor based on acetylcholinesterase was disposable and low cost (about 1 yuan RMB).
文摘In this article, Discrete Homotopy Analysis Method (DHAM), as a new numerical method, is employed to investigate amperometric biosensor at mixed enzyme kinetics and diffusion limitation. Mathematical modeling of the problem is developed utilizing non-Michaelis-Menten kinetics of the enzymatic reaction. Different results are obtained for different values of the dimensionless parameters described in the paper. The presented solution is then compared with the available actual and simulated results.