Heavy metal pollution has long been the focus of attention because of its serious threat to human health and the environment. Surface enhanced Raman spectroscopy (SERS) has shown great potential for metal detection owing to many advantages, including, requiring fewer samples, its minimal damage to specimen, and its high sensitivity. In this work, we proposed a simple and distinctive method, based on SERS, using facile silver film (Ag-film) combined with a DNA molecular switch, which allowed for the highly specific detection of heavy metal mercury ions (Hg2+). When in the presence of Hg2+ ions, the signals from Raman probes attach to single-stranded DNA, which will be dramatically enhanced due to the specific structural change of DNA strands-resulting from the interaction between Hg2+ ions and DNA bases. This SERS sensor could achieve an ultralow limit of detection (1.35 × 10-15 M) for Hg2+ detection. In addition, we applied this SERS sensor to detect Hg2+ in real blood samples. The results suggested that this SERS platform could be a promising alternative tool for Hg2+ detection in clinical, environmental, and food inspection.
Keywords: Ag-film; Hg2+ ions detection; SERS sensor; surface-enhanced Raman spectroscopy (SERS).