Using the nanoimprint-in-metal method to prepare corrugated metal structures for plasmonic biosensors through both surface plasmon resonance and index-matching effects

► Metallic corrugated structure is prepared as highly sensitive plasmonic sensors. ► It can sense both surface plasmon resonance wavelength and index-matching effect. ► A high sensitivity of 800nm/RIU is achieved according to resonance wavelength shift. ► Besides, the linear response of resonance intensity is adopted for sensing as well. ► In the last, the structure demonstrates the ability to be a sensitive biosensor. In this study, we prepared metallic corrugated structures for use as highly sensitive plasmonic sensors. Relying on the direct nanoimprint-in-metal method, fabrication of this metallic corrugated structure was readily achieved in a single step. The metallic corrugated structures were capable of sensing both surface plasmon resonance (SPR) wavelengths and index-matching effects. The corrugated Au films exhibited high sensitivity (ca. 800nm/RIU), comparable with or even higher than those of other reported SPR-based sensors. Because of the unique index-matching effect, refractometric sensing could also be performed by measuring the transmission intensity of the Au/substrate SPR mode—conveniently, without a spectrometer. In the last, we demonstrated the corrugated Au film was capable of sensing biomolecules, revealing the ability of the structure to be a highly sensitive biosensor.