The Effect of Bumpy Structure on Optical Properties of Bimetallic Nanoshells

In this paper, a sensitive bumpy bimetallic nanoshell for detection of thyroid cancer market (Thyroglobulin, Tg) and bovine serum albumin (BSA) proteins is reported. The physical origin of plasmonic properties of bimetal nanoshells is described by plasmon hybridization theory which indicates three intense and clearly separated plasmon modes. The electric field intensity enhancement of the bumpy bimetal nanoshell increases by ~559 %, at the surface of the bump in comparison with a smooth shell. The presence of bumpy structure on the nanoshell surface provides a high enhancement of the resulting Raman signal through an electromagnetic field of the order of 10⁷ which leads to an increase in sensitivity detection of Tg and BSA proteins. In addition, a refractive index (RI) sensitivity of 332.54 nm/RIU is achieved for this bumpy bimetallic nanoshell.