Label-free SPRi assays require just three steps for completion, reducing both time and labor in comparison to other typical bioassays. SPRi results provide users with kinetic binding data, as well as relative signal intensity from the observed interactions, without the need for a detection reagent. Additionally, the sensor chip can be reused after regeneration, and easily manipulated for use in alternative assays, such as binding inhibition or competition. For weak binding interactions, the PlexArray platform has the capability of amplifying the signal by using subsequent stacking injections. Furthermore, the array format of the Nanocapture® chips grants users added flexibility in experimental design. Multiple samples can be sequentially injected and interactions observed with any immobilized ligands on a single chip.