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1.
This paper presents a mathematical model of a potentiometric biosensor based on a potentiometric electrode covered with an
enzyme membrane. The model is based on the reaction–diffusion equations containing a non-linear term related to theMichaelis–Menten
kinetics of the enzymatic reaction. Using computer simulation the influence of the thickness of the enzyme membrane on the
biosensor response was investigated. The digital simulation was performed using the finite difference technique. Results of
the numerical simulation were compared with known analytical solutions.
相似文献
2.
This paper presents a two-dimensional-in-space mathematical model of amperometric biosensors with perforated and selective
membranes. The model is based on the diffusion equations containing a non-linear term of the Michaelis–Menten enzymatic reaction.
Using numerical simulation of the biosensors action, the influence of the geometry of the perforated membrane on the biosensor
response was investigated. The numerical simulation was carried out using finite-difference technique. The calculations demonstrated
non-linear and non-monotonous change of the biosensor steady-state current at various degree of the surface of the perforated
membrane covering. The non-monotonous behaviour of the biosensor response was also observed when changing the thickness of
the perforated membrane. 相似文献
3.
Mechanisms controlling the sensitivity of amperometric biosensors in flow injection analysis systems
Darius Baronas Feliksas Ivanauskas Romas Baronas 《Journal of mathematical chemistry》2011,49(8):1521-1534
This paper numerically investigates the sensitivity of an amperometric biosensor acting in the flow injection mode when the
biosensor contacts an analyte for a short time. The analytical system is modelled by non-stationary reaction-diffusion equations
containing a non-linear term related to the Michaelis-Menten kinetics of an enzymatic reaction. The mathematical model involves
three regions: the enzyme layer where enzymatic reaction as well as the mass transport by diffusion takes place, a diffusion
limiting region where only the diffusion takes place, and a convective region. The biosensor operation is analysed with a
special emphasis to the conditions at which the biosensor sensitivity can be increased and the calibration curve can be prolonged
by changing the injection duration, the permeability of the external diffusion layer, the thickness of the enzyme layer and
the catalytic activity of the enzyme. The apparent Michaelis constant is used as a main characteristic of the sensitivity
and the calibration curve of the biosensor. The numerical simulation was carried out using the finite difference technique. 相似文献
4.
Abhijith KS Kumar PV Kumar MA Thakur MS 《Analytical and bioanalytical chemistry》2007,389(7-8):2227-2234
An amperometric principle-based biosensor containing immobilized enzyme tyrosinase has been used for detection of polyphenols
in tea. The immobilized tyrosinase-based biosensor could detect tea polyphenols in the concentration range 10–80 mmol L−1. Immobilization of the enzyme by the crosslinking method gave good stable response to tea polyphenols. The biosensor response
reached the steady state within 5 min. The voltage response was found to have a direct linear relationship with the concentration
of polyphenols in black tea samples. Enzyme membrane fouling was observed with number of analyses with a single immobilised
enzyme membrane. The tyrosinase-based biosensor gave maximum response to tea polyphenols at 30°C. The optimum pH was 7.0.
This biosensor system can be applied for analysis of tea polyphenols. Variation in the biosensor response to black tea infusions
gave an indication of the different amounts of theaflavins in the samples, which is an important parameter in evaluating tea
quality. A comparative study of the quality attributes of a variety of commercially available brands of tea were performed
using the biosensor and conventional analytical techniques such as spectrophotometry. 相似文献
5.
S. Hashemnia Sh. Khayatzadeh M. Hashemnia 《Journal of Solid State Electrochemistry》2012,16(2):473-479
A new tyrosinase-based biosensor was developed for detection of phenolic compounds using composite film of multiwall carbon
nanotube (MWCNT)/dimethylditetradecylammonium bromide (DTDAB)/tyrosinase (Tyr) on a Nafion-incorporated carbon paste electrode.
The biosensor showed a sensitive electrochemical response to the reduction of the oxidation products of different phenolic
compounds (phenol, catechol, p-cresol, and p-chlorophenol) by dissolved O2 in the presence of the immobilized enzyme. The effects of pH, operating potential, MWCNT concentration, and the DTDAB/Tyr
ratio on electrochemical response were explored for optimum analytical performance. The biosensor exhibited a linear response
range of 1.5–25.0, 2.0–15.0, 2.0–15.0, and 2.5–25.0 μM and sensitivity of 2,900, 3,100, 3,100, and 1,500 μA/mM for phenol,
catechol, p-cresol, p-chlorophenol, respectively. In addition, the response of the enzyme electrode showed Michaelis–Menten behavior at concentrations
of the phenolic compounds higher than 5.0 μM. The stability and the application of the biosensor were also evaluated. 相似文献
6.
Modelling synergistic action of laccase-based biosensor utilizing simultaneous substrates conversion
Evelina Gaidamauskaitė Romas Baronas Juozas Kulys 《Journal of mathematical chemistry》2011,49(8):1573-1586
The response of a laccase-based amperometric biosensor that acts in a synergistic manner was modelled digitally. A mathematical
model of the biosensor is based on a system of non-linear reaction diffusion equations. The modelling biosensor comprises
three compartments, an enzyme layer, a dialysis membrane and an outer diffusion layer. By changing input parameters the biosensor
action was analysed with a special emphasis to the influence of the species concentrations on the synergy of the simultaneous
substrates conversion. The digital simulation was carried out using the finite difference technique. 相似文献
7.
R. Baronas F. Ivanauskas R. Maslovskis P. Vaitkus 《Journal of mathematical chemistry》2004,36(3):281-297
This paper presents a sensor system based on a combination of an amperometric biosensor acting in batch as well as flow injection analysis with the chemometric data analysis of biosensor outputs. The multivariate calibration of the biosensor signal was performed using artificial neural networks. Large amounts of biosensor calibration as well as test data were synthesized using computer simulation. Mathematical and corresponding numerical models of amperometric biosensors have been built to simulate the biosensor response to mixtures of compounds. The mathematical model is based on diffusion equations containing a non-linear term related to Michaelis–Menten kinetics of the enzymatic reaction. The principal component analysis was applied for an optimization of calibration data. Artificial neural networks were used to discriminate compounds of mixtures and to estimate the concentration of each compound. The proposed approach showed prediction of each component with recoveries greater that 99% in flow injection as well as in batch analysis when the biosensor response is under diffusion control. 相似文献
8.
A mathematical model of amperometric biosensors in which chemical amplification by cyclic substrate conversion takes place in a single enzyme membrane has been developed. The model involves three regions: the enzyme layer where enzyme reaction as well as mass transport by diffusion takes place, a diffusion limiting region where only the diffusion takes place, and a convective region where the analyte concentration is maintained constant. Using computer simulation the influence of the thicknesses of the enzyme layer and the diffusion region on the biosensor response was investigated. This paper deals with conditions when the mass transport in the exterior region may be neglected to simulate the biosensor response in a well-stirred solution. The digital simulation was carried out using the finite difference technique. 相似文献
9.
Emregül E 《Analytical and bioanalytical chemistry》2005,383(6):947-954
A superoxide dismutase (SOD) biosensor for determination of superoxide radicals has been developed by immobilization of superoxide
dismutase within gelatin (G) on a Pt electrode surface. The properties of the biosensor have been investigated and optimum
conditions–enzyme concentration, glutaraldehyde concentration, and pH–were determined. The response of the G-SOD biosensor
was proportional to concentration and the detection limit was 0.01 mmol L−1 at a signal-to-noise ratio of 3. The biosensor retained 89% and 60% of its sensitivity after use for three and four weeks,
respectively. Immobilization of SOD on gelatin provides a biocompatible microenvironment around the enzyme and stabilizes
the activity of the enzyme very efficiently. The superoxide dismutase biosensor was used to determine the antioxidant properties
of acetylsalicylic acid-based drugs and the anti-radical activity of healthy and cancerous human brain tissues. 相似文献
10.
A reaction–diffusion system consisting of one, two or three chemical species and taking place in an arbitrary number of spatial
dimensions cannot exhibit Turing instability if none of the reaction steps express cross‐inhibition. A corollary of this result
– obtained by elementary calculations – underlines the importance of nonlinearity in the formation of stationary structures,
a kind of self‐organization on a chemical basis. Relations to global stability of reaction–diffusion systems, and results
on multispecies systems are also mentioned. The statements are not restricted to mass action type models. As a by‐product,
the solution of a basic inverse problem of formal kinetics is also presented which extends a previous result by Hárs and Tóth
(1981) to models with arbitrary – including rational – functions as reaction rates so often occurring, e.g., in enzyme kinetics.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
G. Rahamathunissa P. Manisankar L. Rajendran K. Venugopal 《Journal of mathematical chemistry》2011,49(2):457-474
A mathematical model of steady state mono-layer potentiometric biosensor is developed. The model is based on non stationary
diffusion equations containing a non linear term related to Michaelis-Menten kinetics of the enzymatic reaction. This paper
presents a complex numerical method (He’s variational iteration method) to solve the non-linear differential equations that
describe the diffusion coupled with a Michaelis-Menten kinetics law. Approximate analytical expressions for substrate concentration
and corresponding current response have been derived for all values of saturation parameter α and reaction diffusion parameter
K using variational iteration method. These results are compared with available limiting case results and are found to be in
good agreement. The obtained results are valid for the whole solution domain. 相似文献
12.
Ruixia Han Lin Cui Shiyun Ai Huanshun Yin Xianggang Liu Yanyan Qiu 《Journal of Solid State Electrochemistry》2012,16(2):449-456
A tyrosinase (Tyr) biosensor has been constructed by immobilizing tyrosinase on the surface of Mg–Al–CO3 hydrotalcite-like compound film (HTLc) modified glassy carbon electrode (GCE) for the determination of polyphenols. The negatively
charged tyrosinase was adsorbed firmly on the surface of a positively charged HTLc/GCE by electrostatic interactions and retained
its activity to a great degree. The modified electrode was characterized by cyclic voltammetry and AC impedance spectra. Polyphenols
were determined by a direct reduction of biocatalytically generated quinone species. The different parameters, including pH,
temperature, and enzyme loading were investigated and optimized. Under the optimum conditions, Tyr/HTLc electrode gave a linear
response range of 3–300, 0.888–444, and 0.066–396 μM with a detection limit (S/N = 3) of 0.1, 0.05, and 0.003 μM for catechol,
caffeic acid, and quercetin, respectively. In addition, the repeatability and stability of the enzyme electrode were estimated.
Total polyphenol contents of real samples were also determined to study the potential applicability of the Tyr/HTLc/GCE biosensor. 相似文献
13.
A. H. Parente E. T. A. Marques W. M. Azevedo F. B. Diniz E. H. M. Melo J. L. Lima Filho 《Applied biochemistry and biotechnology》1992,37(3):267-273
A biosensor for glucose utilizing kinetics of glucose oxidase (EC 1.1.3.4.) was developed. The enzyme was immobilized on polyaniline
by covalent bonding, using glutaraldehyde as a bifunctional agent. The system showed a linear response up to 2.2 mM of glucose
with a response time of 2.5–4.0 min. In addition, the immobilized enzyme had a higher activity between pH 6.5 and 7.5. The
system retained 50% of its activity after 30 d of daily use. The optical absorption spectra of the polyaniline/glucose oxidase
electrode after glucose had been added to the buffer solution showed that the absorption band around 800 nm had changed considerably
when glucose was allowed to react with the electrode. This optical variation makes polyaniline a very promising polymer for
use as a support in optical sensor for clinical application. 相似文献
14.
F. Ivanauskas I. Kaunietis V. Laurinavičius J. Razumienė R. Šimkus 《Journal of mathematical chemistry》2008,43(4):1516-1526
Plate-gap model of enzyme doped porous electrode was utilized in order to calculate apparent Michaelis constants () and apparent maximal currents () of modeled amperometric biosensor for the wide range of given reaction/diffusion parameters. It was found that of plate-gap biosensor linearly depends on when rates of enzymatic reaction are lower than critical. Theoretically predicted linear correlation between apparent parameters
was observed experimentally for the case of carbon paste electrodes, which were modified by PQQ-dependent alcohol dehydrogenases.
At overcritical rates (or apparent maximal currents), is practically independent on Michaelis constant of soluble enzyme. Therefore, apparent Michaelis constant can be regarded
as biosensor’s topology representing parameter which, in fact, is not related to the specificity of enzyme kinetics. High
and rate-independent values of indicate that reaction proceeds at substrate-exposed top layer of the gap. In this case, reaction–diffusion system formally
is stratified into separate reaction (top) and diffusion (bottom) zones. Topology of such reaction–diffusion system reminds
“inverted” planar electrode, which contains diffusion layer below reaction layer. The net effect of plate-gap topology of
working electrode on apparent Michaelis constant is similar to the effect of diffusion layer covering enzymatic planar electrode. 相似文献
15.
On the basis of the isoelectric point of an enzyme and the doping principle of conducting polymers, choline oxidase was doped
in a polyaniline film to form a biosensor. The amperometric detection of choline is based on the oxidation of the H2O2 enzymatically produced on the choline biosensor. The response current of the biosensor as a function of temperature was determined
from 3 to 40°C. An apparent activation energy of 22.8 kJ·mol−1 was obtained. The biosensor had a wide linear response range from 5 × 10−7 to 1 × 10−4 M choline with a correlation coefficient of 0.9999 and a detection limit of 0.2 μM, and had a high sensitivity of 61.9 mA·M−1·cm−2 at 0.50 V and at pH 8.0. The apparent Michaelis constant and the optimum pH for the immobilized enzyme are 1.4 mM choline
and 8.4, respectively, which are very close to those of choline oxidase in solution. The effect of selected organic compounds
on the response of the choline biosensor was studied. 相似文献
16.
Wang CY Tan XR Chen SH Hu FX Zhong HA Zhang Y 《Applied biochemistry and biotechnology》2012,166(4):889-902
One-step synthesis method was proposed to obtain the nanocomposites of platinum nanoclusters and multiwalled carbon nanotubes
(PtNCs–MWNTs), which were used as a novel immobilization matrix for the enzyme to fabricate glucose biosensor. The fabrication
process of the biosensor was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy
and scanning electron microscope. Due to the favorable characteristic of PtNCs–MWNTs nanocomposites, the biosensor exhibited
good characteristics, such as wide linear range (3.0 μM–12.1 mM), low detection limit (1.0 μM), high sensitivity (12.8 μA mM−1), rapid response time (within 6 s). The apparent Michaelis–Menten constant (
Km\textapp K_m^{\text{app}} ) is 2.1 mM. The performance of the resulting biosensor is more prominent than that of most of the reported glucose biosensors.
Furthermore, it was demonstrated that this biosensor can be used for the assay of glucose in human serum samples. 相似文献
17.
A solid-state pH sensor based on a self-plasticizing film of methacrylic-acrylic copolymer was developed. The sensor was able
to detect changes in pH after tridodecylamine ionophore was immobilized together with a lipophilic anionic salt. The pH sensor
exhibited almost a Nemstian response (57.6 mV pH−1) with a linear pH response range of 6–10. It demonstrated a fast response (<2 min) to changes in pH and good selectivity
against other common cations such as sodium, potassium, magnesium, lithium, and calcium. The sensor has a shelf life of at
least 30 days without an obvious deterioration in response. By depositing a layer of poly(hydroxylethymethacrylate) immobilized
with enzyme acetylcholinesterase on top of the pH selective methacrylic-acrylic film, the pH sensor was able to detect acetylcholine
chloride (AChCl). The linear response range of the potentiometric biosensor to AChCl was dependent on the buffer concentrations
used, and for a buffer concentration less than 1 mM, the linear response range obtained was 3.98–31.62 μM.
The text was submitted by the authors in English 相似文献
18.
Chunyan Yang Zhujun Zhang Zuolong Shi Pan Xue Pingping Chang Ruifang Yan 《Analytical and bioanalytical chemistry》2010,397(7):2997-3003
A novel enzyme reactor was prepared using calcium alginate fiber (CAF) and amine-modified nanosized mesoporous silica (AMNMS)
as a support. Combination of the adsorption of the enzyme on AMNMS with the cage effect of the polymer greatly increases the
catalytic activity and the stability of the immobilized enzyme. It was shown that the lifetime, stability, and catalytic activity
of the enzyme reactor were greatly improved by incorporating AMNMS into CAF to efficiently encapsulate the enzyme. Glucose
oxidase was chosen as a model enzyme to explore the possibility of using CAF–AMNMS as a matrix for enzyme immobilization in
the design of a chemiluminescence (CL) flow-through biosensor. The sensitivity of the flow-through biosensor combined with
a novel luminol-diperiodatonickelate CL system was higher than for other reported CL biosensors. The proposed biosensor exhibits
short response time, easy operation, long lifetime, high catalytic activity, high sensitivity, and simple assembly. 相似文献
19.
A theoretical model of diffusion and reaction in an anisotropic enzyme membrane is presented with particular emphasis on the
application of such membranes in enzyme electrodes. The dynamic response of systems in which the kinetics are linear, which
comprises the practical operating regime for enzyme electrodes in analysis, is investigated via an analytic solution of the
governing differential equations. The response is presented as a function of a single dimensionless group, Μ, that is the
membrane modulus. 相似文献
20.
R. Baronas F. Ivanauskas J. Kulys M. Sapagovas 《Journal of mathematical chemistry》2003,34(3-4):227-242
A two-dimensional-in-space mathematical model of amperometric biosensors has been developed. The model is based on the diffusion equations containing a nonlinear term related to the Michaelis–Menten kinetic of the enzymatic reaction. The model takes into consideration two types of roughness of the upper surface (bulk solution/membrane interface) of the enzyme membrane, immobilised onto an electrode. Using digital simulation, the influence of the geometry of the roughness on the biosensor response was investigated. Digital simulation was carried out using the finite-difference technique. 相似文献