ABSTRACT
The biosensor field has grown enormously since the first demonstration of the biosensor concept by Leland C. Clark, Jr. in 1962. Today's biosensor market is dominated by glucose biosensors, mass-produced enzyme electrodes for the rapid self-diagnosis of blood glucose levels by diabetes sufferers. Here we take a historical look at the inception, growth, and development of the enzyme biosensor field from a commercial viewpoint. The current status of the technology is evaluated and future trends in this dynamic and fast-moving field are also anticipated.
Subject(s)
Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Biosensing Techniques/trends , Blood Glucose Self-Monitoring/instrumentation , Blood Glucose Self-Monitoring/methods , Computational Biology/instrumentation , Computational Biology/methods , Electrodes , Enzymes, Immobilized/chemistry , Enzymes, Immobilized/metabolism , Genomics/instrumentation , Genomics/methods , Humans , Proteomics/instrumentation , Proteomics/methods , Reproducibility of ResultsABSTRACT
A screen-printed three-electrode amperometric biosensor incorporating malic enzyme for the measurement of L-malic acid in apple, potato and tomato horticultural samples has been developed. The working electrode contained 0.38 mU of immobilised enzyme and was fabricated using rhodinised carbon to facilitate NADPH oxidation at an operating potential of +300 mV vs. Ag/AgCl compared with > +600 mV for bare carbon. The linear range of the sensor was 0.028-0.7 mM L-malic acid with relative standard deviations of 3.3-13.3%. When testing with real apple, potato and tomato samples, the sensor accuracy was within 13.7% of a standard commercially available photometric test kit. The sensor approach is cheap, simple to perform and rapid (6 min), requiring only buffer-electrolyte and a small sample volume.
Subject(s)
Biosensing Techniques , Fruit/chemistry , Malates/analysis , Solanum lycopersicum , Malus , Solanum tuberosumABSTRACT
A screen-printed three-electrode amperometric biosensor for the rapid and quantitative measurement of single protein solutions is described. A membrane immobilised protease preparation of broad specificity was used to digest sample protein liberating free amino acids that were subsequently oxidised at a working electrode by immobilised L-amino acid oxidase (L-AAO). The enzymatically generated hydrogen peroxide was determined amperometrically. The fully optimised device required 30 mU L-AAO and 3.94 U protease and had a limit of detection of 170 microg ml(-1) and linearity of response up to 1 mg ml(-1) for Casilan 90 protein. The analytical performance of the device was comparable to that of a commercially available standard photometric protein test kit and required only a 10 microl volume of sample and a single dilution step. Unlike with photometry, the sensor is able to determine the protein content of turbid samples and hence should find widespread applications. The device was simple to use, low-cost and could be mass-produced, yielding results within 4 min of sample addition with acceptable assay repeatability.
Subject(s)
Biosensing Techniques/methods , Proteins/analysis , Amino Acid Oxidoreductases/metabolism , Electrochemistry , L-Amino Acid Oxidase , Reagent Kits, DiagnosticABSTRACT
A major problem when dealing with environmental contamination is the early detection and subsequent surveillance of the contamination. This paper describes the potential of sub-surface sensor technology for the early detection of organic contaminants in contaminated soils, sediments, and landfill sites. Rugged, low-power hydrocarbon sensors have been developed, along with a data-logging system, for the early detection of phase hydrocarbons in soil. Through laboratory-based evaluation, the ability of this system to monitor organic contamination in water-based systems is being evaluated. When used in conjunction with specific immunoassays, this can provide a sensitive and low-cost solution for long-term monitoring and analysis, applicable to a wide range of field applications.
