A simple gold nanoplasmonic SERS method for trace Hg2+ based on aptamer-regulating graphene oxide catalysis

The as-prepared graphene oxide (GO) exhibited a strong catalytic effect on reduction of HAuCl4 by trisodium citrate to form gold nanoplasmons (AuNPs) with a strong surface-enhanced Raman scattering (SERS) effect at 1615cm(-1) in the presence of molecular probe Victoria blue 4R (VB4r). SERS intensity increased with nanocatalyst GO concentration due to the formation of more AuNP substrates. The aptamer (Apt) of Hg2+ can bind to GO to form Apt-GO complexes, which can strongly inhibit nanocatalysis. When target Hg2+ is present, the formed stable Hg2+-Apt complexes are separated from the GO surface, which leads to GO catalysis recovery. The enhanced SERS signal was linear to Hg2+ concentration in the range 0.25-10nmol/L, with a detection limit of 0.08nmol/L Hg2+. Thus, a new gold nanoplasmon molecular spectral analysis platform was established for detecting Hg2+, based on Apt regulation of GO nanocatalysis.