The work was aimed at the development of a biosensor array for the simultaneous determination of six solutes (glutamate, glucose, choline, acetylcholine, lactate, and pyruvate) in aqueous solutions. ...Enzymes selective for these substrates were immobilized on the surface of amperometric platinum disc electrodes and served as bioselective elements of a biosensor array. Direct enzymatic analysis by the developed biosensors provided high sensitivity to the tested substrates (limits of detection were 1–5 μM). The linear ranges of the biosensors were from 0.001–0.01 mM to 0.2–2.5 mM. The influence of solution pH, ionic strength and buffer capacity on the biosensor responses was investigated; the conditions for simultaneous operation of all the bioselective elements were optimized. The absence of any cross-influence of the substrates of enzymatic systems used was shown as well as a high selectivity of the biosensors and the absence of any impact of interfering substances (ascorbic acid, dopamine, cysteine, paracetamol). The developed biosensor array had good response reproducibility and storage stability. The array is suitable for rapid (0.5–1 min) and simple simultaneous determination of glutamate, glucose, choline, acetylcholine, lactate, and pyruvate in aqueous (biological) samples; furthermore, the creation of a single chip with six sensitive elements is possible as well as the addition of other biosensors.
•A biosensor array for neurotransmitter and metabolite determination was created.•It is based on enzymes immobilized on platinum disc electrodes.•Quick response, simplicity, and low cost are advantages of the biosensor array.•The biosensor array can be used for the analysis of aqueous sample composition.
In the review, the principles and main purposes of using multienzyme systems in electrochemical biosensors are analyzed. Coupling several enzymes allows an extension of the spectrum of detectable ...substances, an increase in the biosensor sensitivity (in some cases, by several orders of magnitude), and an improvement of the biosensor selectivity, as showed on the examples of amperometric, potentiometric, and conductometric biosensors. The biosensors based on cascade, cyclic and competitive enzyme systems are described alongside principles of function, advantages, disadvantages and practical use for real sample analyses in various application areas (food production and quality control, clinical diagnostics, environmental monitoring). The complications and restrictions regarding the development of multienzyme biosensors are evaluated. The recommendations on the reasonability of elaboration of novel multienzyme biosensors are given.
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•Biosensors based on cascade, cyclic and competitive enzyme systems are described.•Advantages and limitations of multienzyme electrochemical biosensors are analyzed.•Multienzyme systems allow an extension of the spectrum of detectable substances.•An improvement of the biosensor sensitivity and selectivity is possible.
•Novel biosensor was proposed for determination of patulin inhibitory potency.•Biosensor principle was based on urease inhibition by patulin.•The proposed biosensor was optimized for analysis of ...patulin inhibitory potency.•The developed biosensor was characterized by a high sensitivity to patulin.•Selectivity of the developed biosensor to different groups of toxins was analyzed.
The research is aimed at the development and optimization of conductometric biosensor for determination of the inhibitory potency of patulin and verification of its feasibility after reactivation. A differential pair of gold interdigitated electrodes deposited on the sital substrate was used as the conductometric transducer of a signal. Urease, co-immobilized with bovine serum albumin by cross-linking with glutaraldehyde on the transducer surface, served as a bioselective membrane. The proposed biosensor was optimized for determination of the inhibitory potency of patulin. It was characterized by quite high sensitivity to patulin, good selectivity and signal reproducibility. A multiple restoration of the biosensor activity after use was rendered possible by a cysteine treatment. It was also tested the sensitivity of the biosensor developed to other groups of toxic substances. In the future, the proposed biosensor can be successfully used for the patulin analysis in real samples.
Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous ...particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05–15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis.
The paper presents a simple and inexpensive reusable biosensor for determination of the concentration of adenosine-5′-triphosphate (ATP) in aqueous samples. The biosensor is based on a conductometric ...transducer which contains two pairs of gold interdigitated electrodes. An enzyme hexokinase was immobilized onto one pair of electrodes, and bovine serum albumin-onto another pair (thus, a differential mode of measurement was used). Conditions of hexokinase immobilization on the transducer by cross-linking via glutaraldehyde were optimized. Influence of experimental conditions (concentration of magnesium ions, ionic strength and concentration of the working buffer) on the biosensor work was studied. The reproducibility of biosensor responses and operational stability of the biosensor were checked during one week. Dry storage at −18°C was shown to be the best conditions to store the biosensor. The biosensor was successfully applied for measurements of ATP concentration in pharmaceutical samples. The proposed biosensor may be used in future for determination of ATP and/or glucose in water samples.
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•A conductometric biosensor for determination of adenosine triphosphate was created.•It is based on enzyme hexokinase immobilized on interdigitated planar electrodes.•Quick response, simplicity, and low cost are advantages of the biosensor.•The biosensor can be used in for determination of ATP in water samples.
The aim of this work was to develop an array of biosensors for simultaneous determination of four carbohydrates in solution. Several enzyme systems selective to lactose, maltose, sucrose and glucose ...were immobilised on the surface of four conductometric transducers and served as bio-recognition elements of the biosensor array. Direct enzyme analysis carried out by the developed biosensors was highly sensitive to the corresponding substrates. The analysis lasted 2min. The dynamic range of substrate determination extended from 0.001mM to 1.0–3.0mM, and strongly depended on the enzyme system used. An effect of the solution pH, ionic strength and buffer capacity on the biosensors responses was investigated; the conditions of simultaneous operation of all biosensors were optimised. The data on cross-impact of the substrates of all biosensors were obtained; the biosensor selectivity towards possible interfering carbohydrates was tested. The developed biosensor array showed good signal reproducibility and storage stability. The biosensor array is suited for simultaneous, quick, simple, and selective determination of maltose, lactose, sucrose and glucose.
•We developed an array of 4 conductometric biosensors based on hydrolytic enzymes.•Conditions for simultaneous operation of all biosensors were selected.•Biosensor array showed good signal reproducibility and storage stability.•The possibility of simultaneous selective determination of carbohydrates was shown.
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•The conductometric biosensor based on acetylcholinesterase was characterized.•It was applied for inhibitory analysis of different toxins and toxicants.•Pesticides, heavy metals, ...surfactants, aflatoxin and glycoalkaloids were determined.•Studies showed that the different classes of inhibitors can be distinguished.•Algorithm of analysis of complex multicomponent samples is proposed.
This study was aimed at the development of a conductometric biosensor based on acetylcholinesterase considering the feasibility of its application for the inhibitory analysis of various toxicants. In this paper, the optimum conditions for enzyme immobilization on the transducer surface are selected as well as the optimum concentration of substrate for inhibitory analysis. Sensitivity of the developed biosensor to different classes of toxic compounds (organophosphorus pesticides, heavy metal ions, surfactants, aflatoxin, glycoalkaloids) was tested. It is shown that the developed biosensor can be successfully used for the analysis of pesticides and mycotoxins, as well as for determination of total toxicity of the samples. A new method of biosensor analysis of toxic substances of different classes in complex multicomponent aqueous samples is proposed.
This study aimed at the development and optimization of a potentiometric biosensor based on pH-sensitive field-effect transistors and acetylcholinesterase for aflatoxin B1 determination in real ...samples. Optimal conditions for bioselective elements operation were defined and analytical characteristics of the proposed biosensor were studied. The proposed biosensor characterized high operational stability and reproducibility of signal. Selectivity of acetylcholinesterase-biosensor to aflatoxins in relation to other groups of toxic substances was analyzed. The developed biosensor was applied to the determination of aflatoxin B1 in real samples (sesame, walnut and pea).
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•The new potentiometric biosensor for aflatoxin B1 analysis was created.•The main analytical characteristics of the developed biosensor were studied.•The optimal conditions of biosensor work with real samples were defined.•The developed biosensor was applied for aflatoxin B1 analysis in real samples.
Potentiometric biosensor based on two identical pH-sensitive field-effect transistors for urea determination was developed. Recombinant urease with low affinity to urea (Km=200mM) was immobilized via ...entrapment in PVA/SbQ photopolymer on one transistor and served as a biorecognition element of the biosensor, while bovine serum albumin in PVA/SbQ photopolymer placed on the second transistor was used for reference. Biosensor was characterized by a wide range of urea determination: 0.5–15mM linear range (operational detection range – 0.5–40mM) and quick response time (1–2min). Samples of blood serum and hemodialysate without urea caused no biosensor response. All this allowed analysis of blood serum samples that were diluted 10 times, what led to smaller measurement error in comparison with 100–500 times dilution in case of biosensors based on non-modified urease from soy beans. Urea concentrations in 10 samples of serum were determined; biosensor results correlated well with two control methods of urea measurement. Furthermore, kinetics of decreasing urea concentration in dialysate during hemodialysis was demonstrated. Biosensor measurements of dialysate samples were verified by traditional colorimetric determination of urea. Proposed biosensor can be effectively used for analysis of samples with different concentrations of urea and for hemodialysis control. What is more, characteristics of the biosensor make possible real-time measurements of urea concentration during hemodialysis by pumping dialysis fluid through the working cell. Biosensor showed no significant decrease of responses during 5 month of storage.
Creatine kinase (CK: adenosine-5-triphosphate–creatine phosphotransferase) is an important enzyme of muscle cells; the presence of a large amount of the enzyme in blood serum is a biomarker of ...muscular injuries, such as acute myocardial infarction. This work describes a bi-enzyme (glucose oxidase and hexokinase based) biosensor for rapid and convenient determination of CK activity by measuring the rate of ATP production by this enzyme. Simultaneously the biosensor determines glucose concentration in the sample. Platinum disk electrodes were used as amperometric transducers. Glucose oxidase and hexokinase were co-immobilized via cross-linking with BSA by glutaraldehyde and served as a biorecognition element of the biosensor. The biosensor work at different concentrations of CK substrates (ADP and creatine phosphate) was investigated; optimal concentration of ADP was 1mM, and creatine phosphate – 10mM. The reproducibility of the biosensor responses to glucose, ATP and CK during a day was tested (relative standard deviation of 15 responses to glucose was 2%, to ATP – 6%, to CK – 7–18% depending on concentration of the CK). Total time of CK analysis was 10min. The measurements of creatine kinase in blood serum samples were carried out (at 20-fold sample dilution). Twentyfold dilution of serum samples was chosen as optimal for CK determination. The biosensor could distinguish healthy and ill people and evaluate the level of CK increase. Thus, the biosensor can be used as a test-system for CK analysis in blood serum or serve as a component of multibiosensors for determination of important blood substances. Determination of activity of other kinases by the developed biosensor is also possible for research purposes.
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•Reusable amperometric enzyme biosensor for creatine kinase detection was developed.•Optimal concentrations of creatine phosphate and ADP were studied.•Conditions for measurements of real samples were determined.•Different concentrations of creatine kinase in blood serum were measured.
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