Instruments surface plasmon resonance

Probe Microscopy, Theory Surface Plasmon Resonance, Applications Surface Plasmon Resonance, Instrumentation Surface Plasmon Resonance, Theory ... 

See also Biochemical Applications of Fluorescence Spectroscopy Biomacromolecular Applications of UV-Visible Absorption Spectroscopy Chiroptical Spectroscopy, General Theory Chiroptical Spectroscopy, Orientated Molecules and Anisotropic Systems Ellipsometry Surface Plasmon Resonance, Instrumentation Surface Plasmon Resonance, Theory Surface-enhanced Raman Scattering (SERS), Applications. 

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.

In these sensors, the intrinsic absorption of the analyte is measured directly. No indicator chemistry is involved. Thus, it is more a kind of remote spectroscopy, except that the instrument comes to the sample (rather than the sample to the instrument or cuvette). Numerous geometries have been designed for plain fiber chemical sensors, all kinds of spectroscopies (from IR to mid-IR and visible to the UV from Raman to light scatter, and from fluorescence and phosphorescence intensity to the respective decay times) have been exploited, and more sophisticated methods including evanescent wave spectroscopy and surface plasmon resonance have been applied. 

The techniques developed to study protein interactions can be divided into a number of major categories (Table 31.1), including bioconjugation, protein interaction mapping, affinity capture, two-hybrid techniques, protein probing, and instrumental analysis (i.e., NMR, crystallography, mass spectrometry, and surface plasmon resonance). Many of these methods are dependent on the use of an initial bioconjugation step to discern key information on protein interaction partners. 

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. 

Perkins, E. Squirrell, D., Development of instrumentation to allow the detection of micro organisms using light scattering in combination with surface plasmon resonance, Biosens. 

Metal labels have been proposed to resolve problems connected with enzymes. Metal ions [13-16], metal-containing organic compounds [17,18], metal complexes [19-21], metalloproteins or colloidal metal particles [22-28] have served as labels. Spectrophotometric [22,25], acoustic [25], surface plasmon resonance, infrared [24] and Raman spectroscopic [28] methods, etc. were used. A few papers have been dealing with electrochemical detection. However, electrochemical methods of metal label detection may be viewed as very promising taking into account their high sensitivity, low detection limit, selectivity, simplicity, low cost and the availability of portable instruments. 

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. 

Combination of Surface Plasmon Resonance (SPR) and Optical Waveguide Spectroscopy (OWS) was used for the simultaneous determination of refractive index and film thickness of the hydrogel layers in the Kretschmann configuration [24], The resulting angle scans from the SPR instrument were fit to Fresnel calculations and different layers were represented using a simple box model. A detailed description of this process has been published previously [18]. 

The instrument based upon surface plasmon resonance detection (5,9-111 is now routinely used to measure the binding of an antigen (or antibody) to an immobilized antibody (or antigen) in a flow cell. The technology relies on the covalent immobilization of one of the interacting species and the detection of the adsorbed analyte. The sophistication of this expensive instrumentation makes its use difficult for routine investigations in many laboratories. Furthermore, the models used to extract the rate constants are not always appropriate to the kinetic data analysis [ 12-141. 

Protease assay CMV protease activity was measured using the surface plasmon resonance technology of the BIAcore instrument (Pharmacia Biosensor). Briefly, this instrument was used to quantitate residual uncleaved biotinylated... 

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-... 

Fig. 5.8 Schematic setup of the surface plasmon resonance (SPR) detection unit in a Bia-core instrument. One interaction partner is immobilized on a modified gold surface, whereas the other flows by in solution. On the other side of the sensor chip, a beam of polarized light is reflected by the gold film. The optical phenomenon SPR leads to a re-...

Biosensor instruments such as Biacore (General Electric) exploit the sensitivity of a surface plasmon resonance response to the mass localised near the surface of a sensor chip. Various approaches can be used for kinases. Inhibition in solution assays involve immobilisation of a target definition compound (TDQ on the sensor surface.13,30 A buffer containing the kinase is flowed over the surface so that the protein is able to bind to the immobilised TDC, giving a signal. When test compounds are included in the buffer, they can compete for the TDC-kinase interaction, allowing estimation of Kd. 

Gobi KV, Tanaka H, Shoyama Y, Miura N (2005) Sensor Actuator B Chem 111-112 562 PUiarik M, Homola J (2006) SPR sensor instrumentation. In Homola J (ed) Surface plasmon resonance. Springer Ser Chem Sens Biosens, vol 4. Springer, Berlin Heidelberg New York (in this volume)... 

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