BiaCore instrument

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.

Studies of the interaction of IL-6 and the sIL-6R were monitored by SPR detection using a BIAcore instrument [1] (Pharmacia, Uppsala). Immobilisation of the respective proteins to the carboxymethylated dextran matrix coating the gold sensor chip was performed using the EDC/NHS coupling chemistry as previously described for IL-6 and sIL-6R [3, 7, 8]. Regeneration of the sensor surface for IL-6 and sIL-6R was performed with lOmM HCl for 3 min [8] and 4M MgCl2 in lOmM Tris-HCl buffer, pH 7.4 for 1 min respectively. 

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-... 

The evolution of SPR methodology toward the commercially available BIAcore instrument line was outlined by Liedberg and coworkers [150]. Other commercially... 

These nanometer-thick layers are easily fabricated from commercially available substances, or can at least be synthesized with relative ease [4]. The first applications of self-assembled monolayers (SAM) for biosensor use were described in the late 1980s and originally developed for Biacore instruments [5,6]. Hydroxyl-terminated long chain thiol alkanes were designed for the formation of the SAM on gold. Such layers can be activated for direct Hnkage of various molecules or further derivatized with different chemistries... 

More detailed descriptions of the various covalent couplings will be given in the following section. Notably, a literature review indicates that the car-boxymethyl dextran surface used in Biacore instruments in combination with the amine couphng method is by far the most widely used immobihzation strategy [26]. 

Fig. 19 Configurations and dimensions of various Biacore instrument flow cells. The left-...

Researchers have recently explored the possibility of combining the BiaCore instrument with MS, in which analytes immobilized on the sensor chip were analyzed with MALDI-TOF directly from the area of the flow cells (Fig. 14.57a) [310,... 

BIAcore AB is the main supplier of automated SPR detection systems (BIAcore 3000, TlOO, and more, see www.BIAcore.com) other suppliers are Texas Instruments (Spreeta and TISPR-I) and Nippon Laser and Electronics (SPR-670). In 2004, 88% of publications that reported the use of SPR indicated that the data were generated with BIAcore instruments [4]. Therefore, in the following the focus will be on BIAcore instruments and BIAcore nomenclature will be used. 

SPR chips coated with a carboxymethyl dextran matrix are supplied commercially by Biacore, a leading manufacturer of SPR instruments. Similar technique can be used for preparation of carboxymethyl dextran matrix on Me(Si)Ox surfaces on which -OH groups are generated by reaction with 3-glycidoxypropyltrimethoxysilane13. 

SPR method is currently well established and used in analysis of affinity interactions. The commercial instruments produced by Biacore AB or Texas Instruments are available in the market. Substantial progress in SPR instrumentation is connected also with the possibility to detect simultaneously the affinity interaction from several surfaces [72], This approach has been proved equally effective for detection of thrombin-DNA aptamer interactions [36]. 

The first commercial SPR was launched hy Pharmacia Biosensor AB (presently Swedish BIAcore AB) in 1990. Since then, the device has been refined and now BIAcore [37] offers several models (BIACORE 3000, BIACORE 2000, BIACORE 1000, BIACORE X, J, Q, S51, and C models). The biosensors of BIACORE 1000 to 3000 are fully automated instruments, with a disposable sensor chip, an optical detection unit, an integrated micro-fiuidic cartridge, an autosampler, method programming and control software. Less expensive manually controlled alternatives cU e the BIACORE x and BiacoreQuant . 

BIAcore (BIAcore AB), www.biacore.com Jandratek, Leica, Ibis, Autolab, Texas Instruments (Spreeta), DKTOA, Analytical Microsystems (Biosuplar), NLE (SPR670), HTS Biosystems, Applied Biosystems, GWC, Sensia S.L., Vir Biosensor ASI (Artiflcial Sensing Instrument)... 

Uppsala, Sweden) (BIAcore ) mon resonance-based instrument... 

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