Electromagnetic Energy Redistribution in Coupled Chiral Particle Chain-Film System

Oliveira O, Mejía-Salazar JR. Chiral Plasmonics and Their Potential for Point-of-Care Biosensing Applications

There has been growing interest in using strong field enhancement and light localization in plasmonic nanostructures to control the polarization properties of light. Various experimental techniques are now used to fabricate twisted metallic nanoparticles and metasurfaces, where strongly enhanced chiral near-fields are used to intensify circular dichroism (CD) signals. In this review, state-of-the-art strategies to develop such chiral plasmonic nanoparticles and metasurfaces are summarized, with emphasis on the most recent trends for the design and development of functionalizable surfaces. The major objective is to perform enantiomer selection which is relevant in pharmaceutical applications and for biosensing. Enhanced sensing capabilities are key for the design and manufacture of lab-on-a-chip devices, commonly named point-of-care biosensing devices, which are promising for next-generation healthcare systems.

Enhanced Plasmonic Particle Trapping Using a Hybrid Structure of Nanoparticles and Nanorods

Plasmon-enhanced particle trapping was demonstrated using a hybrid structure of nanoparticles and nanorods. In order to intensify localized surface plasmon resonance (LSPR), gold nanoparticles (AuNPs) were deposited on zinc oxide nanorods (ZnONRs). The synergistic effect caused by the hybrid structure was identified experimentally. Numerical analysis revealed that the LSPR-induced photophysical processes such as plasmonic heating and near-field enhancement were improved by the existence of ZnONRs. The role of the ZnONR in enhancing the particle-trapping velocity was explored by examining the scattered electric field, Poynting vector, and temperature gradient over the nanostructures calculated from the simulation. It was found that polystyrene microparticles and Escherichia coli cells were successfully trapped by using the ZnONR/AuNP plasmonic structure. A relatively high dielectric constant and nanorod geometry of ZnO enabled the hybrid substrate to enhance trapping performance, compared with a control case fabricated using only gold nanoislands.