Fabrication and characterization of rhombic silver nanoparticles for biosensing

Fabrication and characterization of rhombic silver nanoparticles array being used as a localized surface plasmon resonance (LSPR)-based nano-biosensor were reported in this paper. The sensor consists of a rhombic Ag nanoparticles array with single particle dimension of ∼140 nm in-plane width and 47 nm out-of-plane height. Characteristics of the nanoparticles such as extinction spectroscopy properties, refractive index sensitivity, and concentration of the target molecules were analyzed. The LSPR-based extinction spectra of the antigen or antibody with lower concentration were detected. The detection results from 100 nM target molecule indicate a larger peak wavelength shift for the rhombic nanoparticles-based nano-biosensor than that of the reported triangular particles-based biosensor. Using a discrete dipole approximation (DDA) algorithm aided design approach we demonstrated that the refractive index sensitivity is 330 nm per refractive index unit for the fabricated rhombic Ag nanoparticles array.