Enhancement of Surface Plasmon Resonance Signals by Gold Nanoparticles on High-Density DNA Microarrays

Abstract

We have developed a new methodology to fabricate high-resolution DNA microarrays (2500 dots/cm 2 ) in combination with microcontact printing (µCP) and surface plasmon resonance (SPR) imaging. A novel COOHterminated PEG-disulfide with para-carborane (p-carborane) was synthesized as an initiator chemically bound to a gold substrate for surface coupling reactions with NH 2 -terminated DNA. The hybridization between target DNA immobilized on gold nanoparticles and probe DNA arrayed on flat gold substrates was successfully demonstrated by SPR imaging, where nonspecific adsorption was not observed at the array background. The gold nanoparticles on the array give quite high contrast even at low surface coverage with gold nanoparticles (∼10%) by the enhancement effect of optical signals based on nanoscale phenomena. This enhancement effect can be well described by the simulation based on the Maxwell-Garnett theory for the effective dielectric constants and Fresnel's equation.

Highly Stable Au Nanoparticles with Tunable Spacing and Their Potential Application in Surface Plasmon Resonance Biosensors

“…It has been established that the local plasmon coupling between particles can make contributions to the larger shifts of the resonance angles. [27] Additionally, when the particles have a strong plasmon absorption at the excitation wavelength, the SPR angle shifts to a large value. [28] In our case, with the decrease of the interparticle distance, the near-field coupling will happen, and the plasmon absorption band will shift to longer wavelength, and come closer to the excitation wavelength used in our SPR measurement, which results in the larger SPR angle shift and high sensitivity.…”

Challenges and breakthroughs in recent research on self-assembly

“…Also, Tour and coworkers investigated the structures of SAMs and pointed out the possibilities of multilayer formation, based on experiments using thiol-terminated fullerene derivatives (figure 107) [905]. Various polymeric units such as oligo (phenyleneethynylene) [906,907], oligothiophene [908], polyelectrolyte brushes [909,910], polyaniline [911], poly(ethylene glycol) [912], peptide [913], protein [914], DNA [915], nucleotide [916], carbon nanotubes [917,918], coordination cages [919] have been immobilized in SAM structures. SAMs with cyclodextrin [920,921] and calixarene [922] can be used for material sensing through inclusion complex formation.…”

Nanoscale Architectures for Smart Bio-Interfaces: Advances and Challenges

“…Rapid and highly sensitive PNA-DNA hybridization assays have attracted enormous attention for a wide variety of applications ranging from genotyping to molecular diagnosis (Huang et al, 2001;Ito et al, 2007;Nakamura et al, 2006;Kelly et al, 2003). Conventional optical detection systems based on microarrays and real-time PCR involve expensive detection protocols, typically requiring a fluorescent dye and optical sources/detectors; however, this method has become the standard technique for quantifying the extent of hybridization between surface immobilized probes and fluorophore-labeled DNA targets Yin et al, 2011).…”