The FEB method on which Agile is based is fundamentally different from optical techniques. Optical tools such as SPR and BLI systems measure mass-dependent shifts in light, which is adequate for large molecules. However, SPR and BLI platforms struggle to measure small molecule interactions because small molecules elicit correspondingly small sensor responses. To find the needle of signal generated in a large haystack of background noise, time-consuming and error-prone solvent correction is required.
In contrast, FEB is a completely orthogonal, breakthrough technology. It is an electrical technique, not an optical, mass-based method. The size of the molecule being measured is irrelevant on an FEB platform because molecule size doesn’t impact what FEB measures: the change in biosensor conductance caused by a binding interaction at its surface. In fact, small molecules generally create optimal effects on an FEB platform because small molecules have large chemical potential shifts in relation to their volume, which produces a large response with FEB. This makes FEB an excellent orthogonal technique for small molecule and fragment characterization and validation.