Surface plasmon resonance 624 INDEX

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.

The affinity (interaction strength), multiple interactions, and the changes in concentration can be also monitored from those studies. To deliver data in real time, the natural phenomenon of surface plasmon resonance (SPR) is employed. Since the refractive index (r ) at the interface changes as molecules are immobilized on the sensor surface, instant measure of r provides real-time assessment. The Tlcxchip platform exploits grating-coupled SPR (GC-SPR) for this purpose. 

Ronot Trioli, C. Trouillet, A. Veillas, C. Gagnaire, H., Monochromatic excitation of surface plasmon resonance in an optical fibre refractive index sensor, Sens. Actuators A 1996, 54, 589 593... 

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. 

Surface plasmon resonance-MS Coupled to optical sensor surface Flow across sensor surface Change in surface refractive index to detect presence of a binding partner for an immobilized target MS identifies the binding partner (Sonksenetal., 1998 Nelson Krone, 1999)... 

Surface plasmon resonance (SPR) M Mass-induced refractive index change in real time for direct measurement of association and dissociation rate constants... 

The surface plasmon resonance minimum reflectivity in Figure 20-23 shifts by —0.15° when 1 mM NAD+ binds to the imprinted polymer. The shift is not as great for the related species NADH, NADP+, and NADPH, confirming that the imprinted polymer selectively binds NAD+. When the observed reflectivity was fitted to the theoretical response, the polymer film was calculated to be 22 3 nm thick and had a binding capacity of 2.26 xg NAD+/cm2. When 1 mM NAD+ binds to the polymer, the refractive index of the polymer layer changes from 1.45 to 1.40 and the layer thickness increases by 3.0 0.2 nm. 

Fig. 2 Surface plasmon resonance device in the Kretschmann configuration, so is the refractive index of prism, ei is the refractive index of thin metal film (usually Au or Ag), 62 is the refractive index of air, and 0 represents the critical angle...

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