The frequency selective surface (FSS) is a periodic structure with filtering performance for optical and microwave signals. The general periodic arrays made with patterned metallic elements can act as an aperture or patch on a substrate. In this work, two kinds of materials were used to produce unit cells with various patterns. Gold nanoparticles of 25 nm diameter were used to form periodic mon...

Individual silver nanoparticle-conjugated target protein (cTnI) molecules on gold-nanopatterned chip were selectively detected by wavelength dependent-enhanced dark field illumination. Using specific nanoparticles with unique sizes and materials, the immunotargeted nanoparticle on the chips was detected at the single-molecule level by monitoring changes in the plasmonic resonance based on wavel...

An ultra-sensitive colorimetric method to quantitate hundreds of polynucleotide molecules by gold nanoparticles with silver enhancement has been developed. The hybridization products from the target polynucleotides with biotin-labeled probes and gold nanoparticle-functioned oligonucleotides were immobilized to microplates via avidin-biotin system, and the absorbance signals of gold nanoparticle...

We demonstrate that by combining silver nanoparticles and structured gold SSV surfaces the SERS for those molecules that bridge the nanoparticle-cavity gap is preferentially enhanced using 4-mercaptoaniline and 4-mercaptobenzoic acid as examples.

Silver-enhanced nanoparticle-labeled immunoassays provide a simple, low-cost, and effective way of detecting antigens in dilute solutions. The physical mechanisms behind their operation, however, have not been fully investigated. We present a semiquantitative approach for optimizing sandwich nanoparticle immunoassays using an adsorption-controlled kinetic model. Primary antibodies were immobili...

One dimensional metal nanostructures with the capability of guiding electromagnetic energy are attractive for nanoscale optical devices and circuits. These nanostructures can be also excellent candidates for Raman markers that exploit surfaceenhanced Raman scattering (SERS) phenomena. Onedimensional nanostructures show promising capabilities for guiding and confining the exciting light in nanog...

Metal and alloy nanoparticles are increasingly developed for biomedical applications, while a firm understanding of their biocompatibility is still missing. Various properties have been reported to influence the toxic potential of nanoparticles. This study aimed to assess the impact of nanoparticle size, surface ligands and chemical composition of gold, silver or gold-silver alloy nanoparticles...

Silver nanoparticles offer highly attractive properties for many applications, however concern has been raised over the possible toxicity of this material in environmental systems. While it is thought that the release of Ag(+) can play a crucial role in this toxicity, the mechanism by which the oxidative dissolution of nano-silver occurs is not yet understood. Here we address this through the e...

The interaction of nanoparticles with hemoglobin (Hb), a major constituent of red blood cells, is important in nanotoxicity research. We report SERS spectra of Hb using gold and silver nanoparticles at very small nanoparticle : Hb molecule ratios, that is, under conditions relevant for SERS-based nanotoxicity experiments with red blood cells at high sensitivity. We show that the structural info...

We demonstrate theoretically the trapping and manipulating of a gold nanoparticle dimer, using surface plasmon excited by a focused linearly-polarized laser beam on a silver film. We use both finite-difference time-domain force analysis and Maxwell stress tensor to show that the gold nanoparticle dimer can be trapped by a virtual probe pair. A formula is derived to represent the plasmonic field...