Surface plasmon resonance commercialization

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. 

The results summarized above were obtained by using fluorescence based assays employing phospholipid vesicles and fluorescent labeled lipopeptides. Recently, surface plasmon resonance (SPR) was developed as new a technique for the study of membrane association of lipidated peptides. Thus, artificial membranes on the surface of biosensors offered new tools for the study of lipopeptides. In SPR (surface plasmon resonance) systemsI713bl changes of the refractive index (RI) in the proximity of the sensor layer are monitored. In a commercial BIAcore system1341 the resonance signal is proportional to the mass of macromolecules bound to the membrane and allows analysis with a time resolution of seconds. Vesicles of defined size distribution were prepared from mixtures of lipids and biotinylated lipopeptides by extruder technique and fused with a alkane thiol surface of a hydrophobic SPR sensor. 

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. 

AB, Switzerland) in SPR (surface plasmon resonance) studies. The PLL-PEG-biotin-sAV was used for microarray studies as described for the commercial product. A detailed description of the design and physical and chemical characterization of the PLL-grafted PEG monolayer is provided by Ruiz-Taylor et al. (2001). 

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. 

The avidin-biotin interaction has also been used to immobilize antibodies and proteins, especially in commercial systems based on surface plasmon resonance (SPR) measurements (e.g., the BIAcore). The extraordinary affinity (Kl 10-15 M) of avidin (or its bacterial relative, streptavidin) for the vitamin biotin is the basis of this immobilization procedure. A solid support (e.g., glass beads, sensor chip, optical fiber) covered with avidin can be used as an activated carrier for a very sturdy immobilization of previously biotinylated antibodies. In spite of the many methods for biotinylating proteins described in the literature, the use of biotinyl N-hydroxysuccinimide ester (BNHS) and similar derivatives, remains the most useful [65]. 

Radioactivity, chemiluminescence or fluorescence have traditionally been used to monitor signals with protein arrays. The use of fluorescent dyes allows for increased sensitivity of detection, the ability to multiplex detection of several targets, and easy interfacing with detection instrumentation and automation. Surface plasmon resonance spectroscopy is another alternative, but successful development and commercialization has not yet been achieved. 

Abstract Makrolon , a commercially available polycarbonate with a glassy ultramicroporous structure (mean pore-volume 0.1 nm3), was often employed as sensitive layer for optical sensors in recent years. Due to the definite pore volume-distribution, it can be used as a size-selective sensitive layer. The interaction behaviour of Makrolon of different layer-thicknesses under the influence of methanol, ethanol and 1-propanol is characterized by Spectral El-lipsometry (SE), Surface Plasmon Resonance Spectroscopy (SPR)... 

Another technique used for the analysis of receptor-ligand interaction is surface plasmon resonance (SPR), with its first commercially available application in the BIAcore instruments [44] (Fig. 5.8). Like PCS, it allows the determination of kinetics by monitoring the association and dissociation of a receptor-ligand complex in real time. The interaction partners do not necessarily have to be labeled, which is an advantage of the technique. The principle of SPR measurements is based on an optical phenomenon. The core unit in this technique is a sensor chip consisting of a thin gold film with a modified surface attached on one side. One reactant is attached to the modified sensor surface, whereas the other reaction partner flows past this surface in solution. When the two interaction partners form a com-... 

Surface Plasmon Resonance Imaging Whereas most of the technologies we have discussed so far are only developing, SPRi has been available for quite some time, offering quantitative, label-free, robust, and economical interaction detection in a high-throughput format (Fig. 2-11) [36]. Although RIfS and EIS may provide data types similar to those of this technique, SPRi has been commercialized and subsequently developed for routine practical applications much... 

J. Melendez, R. Carr, D. Bartholomew, H. Taneja, S. Yee, C. Jung, C. Furlong, Development of a surface plasmon resonance sensor for commercial applications. Sens. Actuators, B 1997, 39, 375-379. 

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