Reversible, high-affinity surface capturing of proteins directed by supramolecular assembly

The ability to design surfaces with reversible, high affinity protein binding sites represents a significant step forward in the advancement of analytical methods for diverse biochemical and biomedical applications. Herein, we report a dynamic supramolecular strategy to directly assemble proteins on surfaces based on multivalent host-guest interactions. The host-guest interactions are achieved by one-step nanofabrication of a well-oriented β-cyclodextrin host-derived self-assembled monolayer on gold (β-CD-SAM) that forms specific inclusion complexes with hydrophobic amino acids located on the protein’s surface. Cytochrome C, insulin, -chymotrypsin and RNase A are used as model guest proteins. Surface plasmon resonance (SPR) and static time of flight secondary ion mass spectrometry (ToF-SIMS) studies demonstrate that all four proteins interact with the β-CD-SAM in a specific manner via the hydrophobic amino acids on the surface of the protein. The β-CD-SAMs bind the proteins with high nanomolar to single-digit micromolar dissociation constants (KD). Im-portantly, while the proteins can be captured with high affinity, their release from the surface can be achieved under very mild conditions. Our results expose the great advantages of using a supramolecular approach for controlling protein im-mobilization, in which the strategy described herein provides unprecedented opportunities to create advanced bioanalyt-ic and biosensor technologies.