Surface-Enhanced Raman Spectroscopy for DNA Detection by Nanoparticle Assembly onto Smooth Metal Films

Abstract

A simple, sensitive, and reproducible sensing technique is described for the unambiguous detection of unlabeled single-stranded DNA by surface-enhanced Raman spectroscopy (SERS). By self-assembling probe-tethered Ag nanoparticles to a moderately smooth Ag film using the complementary target species, electromagnetic “hot spots” are created which strongly enhance the Raman signal of the species present in the hot spot. These species can include a Raman label (a molecule with a very large Raman cross-section) that dominates the spectrum and generates highly reproducible signals. The self-assembly process does not take place in the absence of the target species. Consequently, a strong SERS signal is observed only in the presence of the target. The SERS signal was also absent in the presence of noncomplementary species. AFM analysis indicates that strong SERS signal intensity arises from only a few surface-bound nanoparticles which generate an enhancement factor ∼105−106 greater than the metal film alone. Notably, this nanoparticle−film DNA detection method does not require any chemical deposition of silver to read out the SERS spectrum from the surface-bound labels.

Surface-Enhanced Raman Spectroscopy

“…Over 5000 research articles, 100 review articles, and several books on SERS have appeared in the literature. Such a large research database provides ample testimony of the impact of SERS on both fundamental and applied studies in fields as diverse as chemistry, physics, materials science, surface science, nanoscience, and the life sciences (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16).…”

Surface Enhanced Raman Scattering (SERS) Using Nanoparticles

“…The technique was used to detect two common probe molecules, R6G and 4-aminothiophenol (4-ATP) at the single molecule level. In another study, Braun et al demonstrated a single molecule SERS sensing technique for the detection of RNA and DNA, in which AgNP were assembled on an Ag film via the complementary target DNA strand, creating a strongly enhanced Raman signal [61]. Over the last decade, there has been considerable interest in SERS single molecule detection of biomolecules such as hemoglobin, glucose, cancer genes, pathogens, biological toxins and viruses [62][63][64][65][66].…”

Flower Shaped Silver Nanostructures: An Efficient Bacteria Exterminator

“…A substantial amount of research has been carried out for the synthesis of Ag nanostructures owing to their wide and potential applications in antibacterial, antimicrobial, SERS and so forth (Wijaya et al, 2009;Braun et al, 2007;Gupta and Silver, 1998;Schultz et al, 2000). The antibacterial activity of Ag nanostructures has been studied and well documented in the literature.…”