Biosensors designed for environmental and food quality control based on screen-printed graphite electrodes with different configurations (original) (raw)
Related papers
Analytica Chimica Acta, 2002
Biosensors for d-lactate and acetaldehyde were developed, based on screen-printed electrodes and NAD + -dependent dehydrogenases. Modification of screen-printed electrodes with the mediator Meldola Blue or with Meldola Blue-Reinecke salt resulted in sensitive, low cost and reliable NADH detectors. The biosensors were realised in two configurations, as disposable and reusable devices. Single-use sensors were obtained by simple deposition of enzyme and cofactor on the surface of mediator-modified electrodes. Chronoamperometry was used for the detection of substrates in small volumes of samples (25 l). Immobilisation of dehydrogenases by entrapment in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ) allowed sensors to be obtained with sufficient operational stability. Amperometry in stirred solutions was the detection technique with biosensors for multiple use. The 3σ detection limits for acetaldehyde were 1 M by amperometry and 6 M by chronoamperometry and for d-lactate-0.03 M and 0.05 M for reusable and disposable biosensors respectively.
Sensors and Actuators B: Chemical, 2001
The aim of the present work is to compare various thick-®lm con®gurations as well as the different enzyme immobilisation techniques used in the design of a pesticide biosensor. Three different strategies are employed for enzyme immobilisation. According to the ®rst strategy the enzyme layer is applied manually onto the transducer (graphite±epoxy composite screen-printed onto copper tracks produced by photolithography technique) and then the immobilisation of enzyme via cross-linking with glutaraldehyde was performed. In the second strategy the biosensor fabrication is based on the screen-printing of an enzyme±hydroxyethyl cellulose (HEC) paste onto the same transducer. The third strategy consists in the biological material incorporation into the graphite±epoxy paste forming a biocomposite. The enzyme remains immobilised in the bulk of the paste which is screen-printed over copper tracks producing the biosensor in a single-step procedure. Analytical performances of biosensors designed by these three different con®gurations are compared. #
Screen-printed biosensors using different alcohol oxidases
Sensors and Actuators B: Chemical, 2001
Low-cost screen-printed sensors consisting of a platinum working electrode, a carbon counter electrode, and an Ag/AgCl pseudoreference electrode were fabricated for the development of alcohol oxidase biosensors. The sensors were fabricated as amperometric transducers for the detection of alcohols in batch systems. A mixture of alcohol oxidase (AOD) with poly(carbamoyl)sulfonate (PCS) hydrogel was used for enzyme immobilization onto the platinum electrodes. Alcohol oxidases from different sources such as from Hansenula sp., from Candida boidinii and from Pichia pastoris were used for immobilization. The performances of the resulting different sensors has been compared and characterized with respect to enzyme load, pH and temperature dependence, response time, recovery time, linear range and sensitivity. The relative response of sensors for different alcohols was measured to evaluate the selectivity of the sensors. The effect of ascorbic acid and sodium sul®te as electrochemical interferents on the sensor's performance was investigated. The continuous operation and storage stability of the sensors were also evaluated. Most of the characterization parameters were found to be superior for sensors with immobilized AOD from Hansenula sp. The sensors were also tested with wine samples. The results obtained by the newly developed biosensors were compared to results obtained by pycnometry, the well-established reference method as well as gas chromatograph method. #
Analytical and Bioanalytical Chemistry, 2007
This review summarizes scientific research activity on biosensors, especially screen-printed, electrodebased biosensors. The basic configurations of biosensors based on screen-printing technology are discussed and different procedures for immobilization of the biorecognition component are reviewed. Theoretical aspects are exemplified by practical environmental and food-analysis applications of screen-printed, electrode-based biosensors.
Amperometric screen-printed biosensor arrays with co-immobilised oxidoreductases and cholinesterases
Analytica Chimica Acta, 2005
Amperometric screen-printed biosensor arrays for detection of pesticides (organophosphates and carbamates) and phenols have been developed. Cholinesterases (AChE and BChE), tyrosinase (TYR), peroxidases (SBP, soybean and HRP, horseradish) and cellobiose dehydrogenase (CDH) were combined on the same array consisting of one Ag/AgCl reference electrode surrounded by eight radially distributed working electrodes of either carbon or platinum. Mainly cross-linking with glutaraldehyde was employed for enzyme immobilisation. The substrates for the enzymes were acetylthiocholine for cholinesterases (ChEs), cellobiose for CDH and hydrogen peroxide for peroxidases. Hydrogen peroxide was generated in the presence of glucose by co-immobilised glucose oxidase (GOx). All measurements were performed in an electrochemical steady state system specially constructed for eight channel screen-printed electrode arrays. The achieved relative standard deviation values calculated for different enzyme substrates (10 measurements) were typically below 7% and one assay was completed within less than 10 min. The detection limits for pesticides and phenols were in the nanomolar and micromolar ranges, respectively. The developed biosensor array was evaluated on wastewater samples. To simplify interpretation of results, the measured data were treated with multivariate analysis-principal component analysis (PCA).
Enzyme Based Amperometric Biosensors for Food Analysis
Electroanalysis, 2002
This review introduces the principles of amperometric detection e.g. oxygen electrodes, hydrogen peroxide electrodes, NADH detection, mediators-aid detection, conductive organic salts and wiring electrodes. A short categorization and description of the materials commonly used for the construction of electrodes, e.g., platinum, glassy carbon, different types of graphite, screen-printed electrodes, rigid carbon-polymer biocomposites, zeolites, clays, and polymeric membranes is given. Approaches to construction of biosensors with respect to various strategies of enzyme immobilization, e.g., physical binding, covalent binding, gel entrapment, electropolymerization, sol-gel techniques and self-assembled architectures are also presented. The requirements and problems for sensing in food industry, examples of enzyme electrodes, published in the literature during the last half-decade, commercial biosensors released into the market along with the current and modern instrumentation, are also presented.
Fundamental and Application of Various Types of Biosensors in Food Analysis
A biosensor is a sensing device comprised of a combination of a specific biological element and a transducer. Microbial biosensor is an analytical device which integrates microorganisms with a physical transducer to generate a measurable signal proportional to the concentration of analytes. In recent years, a large number of microbial biosensors have been developed for environmental, food, and biomedical applications. Biosensors can essentially serve as low-cost and highly efficient devices for this purpose in addition to being used in other day-to- day applications. A “specific biological element” recognizes a specific analyte and the changes in the biomolecule are usually converted into an electrical signal by a transducer. Biosensors are an important alternative in the food industry to ensure the quality and safety of products and process controls with effective, fast and economical methods. Nowadays, a vast majority of the glucose meters are based on electrochemical biosensor technology. The use of enzymatic biosensor technology in food processing, quality control and on-line processes is promising compared to conventional analytical techniques, as it offers great advantages due to size, cost, specificity, fast response, precision and sensitivity. Enzymatic biosensors are a tool with broad application in the development of quality systems, risk analysis and critical control points, and the extent of their use in the food industry is still largely limited by the short lifetime of biosensors, in response to which the use of thermophilic enzymes has been proposed. Oxidase enzymes utilize molecular oxygen for oxidation of Substrate. In microorganisms, the enzymatic degradation of caffeine is brought about by sequential demethylation by an oxygenase, into theobromine or paraxanthine. Amount of caffeine converted by the microorganisms and the amount of oxygen consumed based on which, the amount of caffeine in the sample can be determined. Biosensor against caffeine is an new invention particularly in food Technology and other fields. Biosensors can have a variety of biomedical, industry, and military applications. In spite of this potential, however, commercial adoption has been slow because of several technological difficulties. For example, due to the presence of biomolecules along with semiconductor materials, biosensor contamination is a major issue. Potential applications within the supply chain range from testing of foodstuffs for maximum pesticide residue verification through to the routine analysis of analyte concentrations, such as, glucose, sucrose, alcohol, etc., which may be indicators of food quality/acceptability."Biosensors market is categorized as a growth market is expected to grow from 6.72billionin2009to6.72 billion in 2009 to 6.72billionin2009to14.42 billion in 2016." Biosensor adoption is increasing every year and the number of biosensor applications is continuously growing. Keywords: Specific biological element, Transducer, Analyte concentrations and adoption.
Chemometric analysis of screen-printed biosensor
A multivariate data analysis, partial least-squares regression (PLS) was performed on chronoamperometric data. These data were obtained using a disposable screen-printed NAD + -dependent dehydrogenase biosensor suited to determine propionaldehyde concentration. The influence of several data pre-treatments on prediction ability of the built PLS models was studied. Propionaldehyde determination was efficiently achieved for concentrations ranging from 0.2 to 1.2 mM using a model with six significant latent variables. Treatment of the overall chronoamperometric data (using PLS regression) compared to regression on a single data point of chronoamperograms improved substrate determination reliability: the overall coefficient of variation for the determination of propionaldehyde was reduced from 33 to 15%. This study opened up opportunities for further developments of disposable sensors for field use.