Surface plasmon resonance-type biosensor

Immunosensors have been developed commercially mostly for medical purposes but would appear to have considerable potential for food analysis. The Pharmacia company has developed an optical biosensor, which is a fully automated continuous-flow system which exploits the phenomenon of surface plasmon resonance (SPR) to detect and measure biomolecular interactions. The technique has been validated for determination of folic acid and biotin in fortified foods (Indyk, 2000 Bostrom and Lindeberg, 2000), and more recently for vitamin Bi2. This type of technique has great potential for application to a wide range of food additives but its advance will be linked to the availability of specific antibodies or other receptors for the various additives. It should be possible to analyse a whole range of additives by multi-channel continuous flow systems with further miniaturisation. 

Very few immunosensors are commercially available. The commercial immunosensors are either the detector or bioanalyzer types. The PZ 106 immunosensor from Universal Sensors Inc. (New Orleans, LA) has been used as a detector to measure antibody-antigen reaction. Ohmicron (Newtown, PA) developed a series of pesticide immuno-bioanalyzers that have been used in field tests. Pharmacia Biosensor USA (Piscataway, NJ) recently introduced BIAcore immunodetection system. A combination of a unique flow injection device and surface plasmon resonance (SPR) detection technique provides a real time analysis. A carboxylmethyldextran layer added to plasmon generating gold film is a hydrophobic, activatable, and flexible polymer that provides high antibody and low non-specific bindings. System demonstration at the Institute of Food Technologists (IFT) 1994 meeting in Atlanta drew attention of food scientists. It should easily be adapted for food protein characterization. 

Lee SJ, You B-S, Park JW, Niazi JH, Kim YS, Gu MB (2008) ssDNA aptamer-based surface plasmon resonance biosensor for the detection of retinol binding protein 4 for the early diagnosis of type 2 diabetes. Anal Chem 80 2867-2873... 

Fiber-optic biosensors are analytical devices in which a fiber optic device serves as a transduction element. The usual aim of fiber-optic biosensors is to produce a signal proportional to the concentration of target analyte to which the biological element reacts. Fiber-optic biosensors are based on the transmission of light along silica glass fiber, or POF to the site of analysis. They can be used in combination with different types of spectroscopic technique, e.g. absorption, fluorescence, phosphorescence, or surface plasmon resonance (SPR) (14). 

Low-temperature sensors surface plasmon resonance sensors pellistors biosensors High-temperature electrochemical gas sensors sensors for tough conditions electronic nose RT electrochemical sensors Membranes filters for aU types of sensors SAW sensors cantilever-based sensors... 

The physics of surface plasmons propagating along a metal/dielectric interface has been studied intensively, and their fundamental properties have been found to be in good agreement with theoretical concepts based upon the plasma formulation of Maxwell s theory of electromagnetism. The phenomenon has been utilized extensively by physical scientists in studies of the properties of surfaces and thin films. Current interest in the properties of thin surface coatings stems partly from increased applications to thin film devices and, in particular, to recent developments in biosensor devices. This article focuses on the characterization of the surface plasmon resonance phenomenon, with emphasis on the conditions of optical excitation of plasmon resonance and the theoretical analysis of different types of surface resonances. 

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