Surface Plasmon Resonance
In dealing with biomolecular interactions, researchers at ICx Technologies (www.icxt.com) developed surface plasma resonance (SPR) biosensors for processes such as antibody selection and screening, drug discovery, ligand binding specificity, and gene regulation.
“Our surface is not a hydrogel,” notes John Quinn, Ph.D., CSO, “so you can immobilize things on the surface that behave like they do in solution and retain all biological activity.” He reports that the company licensed the surface plasmon technology but developed the chemistry, software, and microfluidics in-house. Dr. Quinn explains that the 15-nanoliter scale of the microfluidics allows for high mass transport rates and ensures kinetic information and high data quality.
One of the advantages to the SPR system is that it can analyze whole cells. It isn’t necessary to purify the receptor from the cell membrane. The sample is injected across the surface, and the vesicles are captured on the surface. “We have data sets showing high reproducibility of injections and we have data sets showing concentration assays.”
Dr. Quinn says one of the main features was the data set on kinetics. The model conformed exactly to the data set, validating the company’s approach. “In our model fitting, we find that the actual empirical data matched these models very closely.” The analysis software, Qdat, uses the entire data set.
“This technology provides structure function. It also allows thermodynamic analysis—you can repeat kinetic analysis at different temperatures to provide you with the type of bonding involved,” says Dr. Quinn.
There are currently two instruments available: an entry-level device and a semiautomated device, the SensiQ. The company is currently developing a fully automated instrument.