Instrumentation biosensors

Cush R., Cronin J.M., Stewart W.J., Maule C.H., Molloy J., Goddard N. J., The resonant mirror a novel optical biosensor for direct sensing of biomolecular interactions, Part I Principle of operation and associated instrumentation, Biosensors and Bioelectronics 1993 8 347-353. 

R. Cush, J. M. Cronin, W. J. Stewart, C. H. Maule, J. Molloy, and N. J. Goddard, "The Resonant Mirror A Novel Optical Biosensor for Direct Sensing of Biomolecular Interactions Part I Principle of Operation and Associated Instrumentation," Biosensors Bioelectronics 8, 347-354 (1993). 

EC Nice, B Catimel. Instrumental biosensors new perspectives for the analysis of biomolecular interactions. Bioessay 21 339—352, 1999. 

Although iastmmentation is discussed ia many of the analytical articles, there are only a few places ia the Eniyclopedia where it is the primary emphasis (see Analytical methods, hyphenated instruments Automated instrumentation). However, articles relating to materials used either ia or as iastmmeatal compoaeats such as eaergy sources (see Lasers), sampling devices (see Eiber optics), and detectors (see Biosensors Photodetectors SsENSORs) abound. 

The twenty-first century demands novel materials of the scientist. New instruments have made possible the field of nanotechnology, in which chemists study particles between 1 and 100 nm in diameter, intermediate between the atomic and the bulk levels of matter. Nanotechnology has the promise to provide new materials such as biosensors that monitor and even repair bodily processes, microscopic computers, artificial bone, and lightweight, remarkably strong materials. To conceive and develop such materials, scientists need a thorough knowledge of the elements and their compounds. 

The current trend in analytical chemistry applied to evaluate food quality and safety leans toward user-friendly miniaturized instruments and laboratory-on-a-chip applications. The techniques applied to direct screening of colorants in a food matrix include chemical microscopy, a spatial representation of chemical information from complex aggregates inside tissue matrices, biosensor-based screening, and molec-ularly imprinted polymer-based methods that serve as chemical alternatives to the use of immunosensors. 

Figure 7.9. Schematic diagram of a surface plasmon resonance biosensor. One of the binding partners is immobilized on the sensor surface. With the BIACORE instrument, the soluble molecule is allowed to flow over the immobilized molecule. Binding of the soluble molecule results in a change in the refractive index of the solvent near the surface of the sensor chip. The magnitude of the shift in refractive index is related quantitatively to the amount of the soluble molecule that is bound.

For standardised instrumental analytical methods, i.e. biomarkers, biosensors and bioassays, there are well-established standard protocols on the national level, e.g. under Association Francaise de Normalisation (AFNOR), British Standard Institute (BSI), DIN (German Organisation for Standardisation), etc., and all those standards are formed by ISO-Working Groups and by validation studies into ISO - and CEN - Standards. Normal accredited and well-qualified laboratories should be able to perform the monitoring. 

The introduction of optical biosensors has made it possible to obtain data for a large number of macromolecular interactions without the necessity of additional labeling. Here several commercial instruments utilize the effect of Surface Plasmon Resonance (SPR) to detect accumulation of ligands in the sensor matrix. 

Among organic constituent measurements, that of aggregate properties (BOD and COD) and specific parameters (TOC for example) has been well developed for more than 20 years. Concerning BOD, a recent review on biosensors [33] has been published. BOD biofilm-based sensors as well as respirometric systems, other measuring principles, and the commercial BOD instruments are discussed and compared regarding their performance characteristics like linearity, response time, precision, agreement between BOD values obtained from the biosensors and the conventional 5-day test, as well as toxic resistance to various compounds and operational stability. 

Table 6.2 Analytes measured by membrane biosensors (Yellow Springs Instruments)...

PANFILI G, MANZI P, COMPAGNONE D, SCARCIGLIA L and PALLESCHI G (2000), Rapid assay of chohne in foods using microwave hydrolysis and a choline biosensor , J Agric Food Chem, 48, 3403-7. pant I and trennery v c (1995), The determination of sorbic acid and benzoic acid in a variety of beverages and foods by micellar electrokinetic capillary chromatography , Food Chem, 53(2), 219-26. pare j r j and Belanger j m r (1997), Instrumental Methods in Food Analysis. Series Techniques and instrumentation in analytical chemistry - Vol. 18, Amsterdam, Elsevier. 

The flow-through sensors described in this Section comply essentially with the definition of biosensor. This word, like every term used to designate devices of scientific and popular note, has been the object of a number of definitions of both generic and specific scope. In a broad sense, a biosensor is any instrument or technique that measures biomolecules. In stricter terms, Rechnitz defines a biosensor as "a device that incorporates a biochemical or biological component as a molecular recognition element and yields an analytical signal in response to biomolecules" [10]. In between these two... 

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