Single-Chip Multi-Detection Cycles

The same chip can be employed several times to monitor a specific target levels in a sample, thus reducing chip to chip variations and experimental costs.

Multidet
Figure 1. SPR chips utilization cycle.

For certain protein and with the right regeneration conditions8, the functionalized sensor surface can be re-established after an assay and use for multiple detection cycles (Figure 1). Each SPR experiment starts with a bare Au surface on top of which selectivity is built layer-by-layer. Initially, a self-assembled monolayer with a functional head group covers the Au surface to serve as a covalent anchor point to attach probe protein subsequently (step A to C). Once functionalized with the desired protein, the chip surface is exposed to the sample within which target molecules will diffuse toward the sensor's surface to interact with the probe protein (step C to D). After a certain time, dissociation parameters are acquired by flowing buffer only over the sensor (step D to E). Protein-protein interactions with strong affinity remain on the sensor during the buffer only step and to remove them a harsher regeneration buffer is used for a short period of time to avoid denaturing surface-bound proteins (step E to C). Depending on your application and with the right conditions, this cycle can be repeated several time.