We present a novel and simple method for forming hexagonal gold nanoparticle arrays that uses Coulombic interactions between negatively charged gold nanoparticles on positively charged vertically oriented poly(4-vinylpyridine) cylinders formed in a spin cast polystyrene-b-poly(4-vinylpyridine) block copolymer film. Exposure of the block copolymer film to dibromobutane vapor quaternizes and cros...

mediciNe & HealtH/RHode iSlaNd partICleS Can be engIneered to nanometer-size (nm) which are only 1/1,000 the width of a single human hair. Nanoparticles made of gold display strong optical absorption. A special type of gold nanoparticle called hollow gold nanoparticle has a core-shell nanostructure with unique characteristics, including small particle size (~40 nm in diameter), which is an idea...

Most studies have used in vitro systems to test inflammatory responses of nanoparticles; these may not reflect the real biological response of body organs. In fact, certain nanoparticles have provoked opposite effects under in vitro and in vivo conditions. Current understanding of the biocompatibility of gold nanoparticles is controversial. We studied the acute (1 day) and sub-chronic (5 days) ...

A novel microfluidic molding process was used to form microscale features of gold nanoparticles on polyimide, glass, and silicon substrates. This technique uses permeation pumping to pattern and concentrate a nanoparticle ink inside microfluidic channels created in a porous polymer template in contact with a substrate. The nanoparticle ink is self-concentrated in the microchannels, resulting in...

We experimentally demonstrate cascaded field enhancement by means of gold nanoparticle dimer and trimer antennas. The local field enhancement is probed by single-molecule fluorescence using fluorophores with high intrinsic quantum efficiency (Q(0)>80%). Using a self-similar trimer antenna consisting of 80, 40, and 20 nm gold nanoparticles, we demonstrate a fluorescence enhancement of 40 and a s...

a new competitive immunochromatography (icg) strip test based on polyclonal antibody (pab) conjugated with gold nanoparticles (nps) was developed and its applications for primary screening of immunoglobulin (ig) a in serum were evaluated. nanocolloidal gold as the detection reagent, with an average particle diameter of 20 nm, was synthesized and labelled pab. the antibody-nanocolloidal gold pro...

A highly sensitive and selective colorimetric lead biosensor based on DNAzyme-directed assembly of gold nanoparticles is reported. It consists of a DNAzyme and its substrate that can hybridize to a 5'-thio-modified DNA attached to gold nanoparticles. The hybridization brings gold nanoparticles together, resulting in a blue-colored nanoparticle assembly. In the presence of lead, the DNAzyme cata...

We report what we believe is the first experimental confirmation at visible light wavelengths of the backscattering enhancement phenomenon of the photonic nanojet. A specially designed sample stage consisting of a multilayered sandwich of glass, solid polydimethylsiloxane (PDMS), and liquid PDMS, permitted the precise positioning of a gold nanoparticle of diameter between 50 and 100 nm within t...

Advances in nanosciences are having a significant impact in many areas of research. The impact of new nanotechnologies has been particularly large in biodiagnostics, where a number of nanoparticle-based assays have been introduced for biomolecules detection. To date, applications of nanoparticles have largely focused on DNA-functionalised gold nanoparticles used as the target-specific probes. T...

Multi-color gold-nanoparticle-based tags (nanotags) are synthesized for combined surface-enhanced Raman spectroscopy (SERS) and x-ray computed tomography (CT). The nanotags are synthesized with quasi-spherical gold nanoparticles encoded with a reporter dye (color), each with a unique Raman spectrum. A library of nanotags with six different colors were synthesized for a range of gold nanoparticl...