SERS detection of DNA hybridization on a graphene oxide plasmonic nanoplatform: Influence of DNA sequence length

This study investigates DNA hybridization using surface-enhanced Raman spectroscopy (SERS) on a graphene oxide plasmonic nanoplatform. We examined polyA-polyT systems of varying lengths (10, 15, and 20 bases) and polyT concentrations (10−7 M to 10−4 M). We observed an inverse correlation between the 732 cm−1 (adenine) and 765 cm−1 (phosphate backbone) band areas upon hybridization. Mainly, after hybridization, the 732 cm−1 band area decreases. This is attributed to dsDNA shortening and reorientation, placing it in a weaker electromagnetic field and exposing the SERS-active phosphate backbone. This correlation diminishes with shorter DNA strands (15 bases) and disappears for 10-base strands, due to their increased distance from the SERS “hot-spot.” These findings demonstrate SERS's potential for determining DNA strand structure and orientation within SERS hot-spots.