Fiber Optic Plasmonic Sensors Based on Nanodome Arrays with Nanogaps

Abstract

In this study, a high-performancefiber optic surface plasmon resonance (FO-SPR) sensor using a dome array withnanogaps (DANG) is proposed for label-free real-time detection of biomolecules. A novel and simple method using polymer beadsenables high sensitivity by allowing hotspots with nanometer spacing between the Au dome and the surroundingfilm. Thenanodome structure, which comprises a polymer core and a Au shell, induces a localized surface plasmon, expands the sensing area,and extensively enhances the electromagneticfield. The refractive index sensitivity of the FO-SPR sensor with nanostructures, i.e.,with nanogaps and nanodomes, was found to be 7.8 times higher than that of the FO-SPR sensor without nanostructures. Theproposed sensor achieved a low detection limit of 38 fg/mL while quantifying thyroglobulin antibody-antigen interactions andexhibited excellent selectivity. In addition, it helped detect serum samples with a 103% recovery rate.