A plasmonic turn-on insulin sensing platform on centimeter scale nanostructure arrays

We present a plasmonic turn-on biosensing assay for insulin detection via aptamer DNA based on the plasmonic interaction of centimeter scale gold/silver double-layer nanodisk arrays and gold nanoparticles. The large-scale nanostructures were fabricated by laser interference lithography technique. The detecting optical signal-extinction spectra of the system were monitored by UV-visible spectrophotometry. The 3D finitedifference time-domain simulation was used to observe the plasmonic interaction of the sensing system. The platform exhibits an exceptionally large turn-on signal by a 120 nm red shift of the localized surface plasmonic resonance peak, results in the limit detection of 140 pM. The centimeter-scale localized surface plasmon resonance nanostructures combined with turn-on design scheme would offer a promising sensor-on-chip biosensing platform.