Nonlabeled detection of specific intermolecular bondings by terahertz surface plasmon resonance of topological insulator

The terahertz (THz) band, which corresponds to intermolecular binding energy, is the key to achieving a nonlabeled biosensor. To realize high-sensitivity binding detection, we focused on surface plasmon resonance (SPR) in the THz range. Using THz-SPR enhanced a in topological insulator, we expect to observe the synergistic effects of two resonance phenomena, namely intermolecular vibrational resonance and SPR. In this Letter, we report the nonlabeled detection of biomolecular binding by the topological insulator THz-SPR. Bi2Se3 was processed in a microribbon array to enhance the SPR in the THz range. The avidin-biotin specific binding, which is similar to the antigen-antibody reaction mechanism and has powerful interactions, was observed owing to enhancement by Bi2Se3 THz-SPR. This work paves the way for a system to directly measure specific molecular bonds using topological insulators.