Probing Peptide Adsorption Kinetics and Regioselectivity via Multipolar Plasmonic Modes of Gold Resonators

Efficient peptide adsorption on metasurfaces is essential for advanced biosensing applications. In this study, we demonstrate how ellipsometric measurements coupled with numerical simulations allow for real-time tracking of temporin-SHa peptide adsorption on gold metasurfaces. By characterizing spectral shifts at 660 nm, 920 nm, and 1000 nm, we reveal a rapid saturation of surface coverage after 3.5 hours, with a significant preferential adsorption at the resonator ends. Our approach provides a novel methodology for monitoring peptide binding, which could be applied to a wide range of biosensor designs.