Nanoparticles with Raman Spectroscopic Fingerprints for DNA and RNA Detection

TLDR

Gold nanoparticle probes labeled with oligonucleotides and Raman dyes have enabled multiplexed oligonucleotide detection. The authors aim to combine high‑sensitivity, high‑selectivity scanometric detection with multiplexing and ratioing by using Raman tags as narrow‑band spectroscopic fingerprints. They coat gold nanoparticles with silver to create a SERS promoter, then capture dye‑labeled particles on a microarray chip where the Raman tags provide distinct spectral fingerprints. The platform distinguished six DNA targets and two RNA SNP targets, achieving an unoptimized detection limit of 20 fM.

Abstract

Multiplexed detection of oligonucleotide targets has been performed with gold nanoparticle probes labeled with oligonucleotides and Raman-active dyes. The gold nanoparticles facilitate the formation of a silver coating that acts as a surface-enhanced Raman scattering promoter for the dye-labeled particles that have been captured by target molecules and an underlying chip in microarray format. The strategy provides the high-sensitivity and high-selectivity attributes of gray-scale scanometric detection but adds multiplexing and ratioing capabilities because a very large number of probes can be designed based on the concept of using a Raman tag as a narrow-band spectroscopic fingerprint. Six dissimilar DNA targets with six Raman-labeled nanoparticle probes were distinguished, as well as two RNA targets with single nucleotide polymorphisms. The current unoptimized detection limit of this method is 20 femtomolar.