Biosensor Core

Special Features of Biacore® Instrumentation

  • They are sensitive. The Biacore® 3000 can detect clear signals over low backgrounds in binding studies of molecules as small as maltose (360 Da). The Biacore® T200, which the Biosensor Core has recently installed, is even more sensitive and reliable in studies of low molecular weight ligands, due to the much lower noise in the system.
  • Many different surface chemistries are available from GE Healthcare, allowing a wide variety of bimolecular binding reactions to be analyzed. The most frequently used sensor chip, the CM5, is constructed with a thin layer of dextran on the surface of the gold foil exposed to the medium. The dextran can be readily derivatized to produce surfaces containing a variety of generally useful reagents, such as streptavidin (e.g., the SA sensor chip) and antibodies. Metal chelation with the NTA chip and hydrophobic derivatives, made with the HPA chip, are also available. In addition, GE manufactures a series of unmodified or altered chemical surfaces in the “Pioneer Chip” series. All of these chips can be used multiple times, reducing the cost per assay.
  • The Biacore® 3000 and the Biacore® T200 have 4 independently monitored channels. This effectively creates 4 potentially identical biosensor surfaces that can either be used independently, in pairs, or all together. The same or different ligands can be immobilized on each of the sensor surfaces, and binding to each can be compared simultaneously to analyze binding kinetics or specificity. This reduces the noise of non-specific binding, allows for correction of artifacts due to the flow of solution over the biosensor, and increases the accuracy of measurement or antibodies to fusion protein partners, such as glutathione-S-transferase (GST) or epitope tags.
  • The hydraulic system minimizes the volume of samples used and recovery of samples is easy. The Biacore® instruments use an injection loop like that of HPLC units. The dead volume is small (< 2 µl in multichannel mode), and volumes as small as 5 µl/channel can be analyzed.
  • The unit is easy to program and to operate robotically, permitting unattended use for extended periods of time. Runs can be programmed overnight or even over a weekend.
  • Curve-fitting is easy. Biacore®‘s software facilitates “global curve-fitting,” permitting the determination of kinetic and binding constants from a set of binding curves generated with different concentrations of analyte in a single set of calculations. Software features, termed “Wizards,” make data collection and analysis easy. More advanced software permits the extraction of kinetic and binding constants under conditions in which mass transport effects may be significant.