Detection of Mercury with a Surface-Enhanced Raman Scattering Biosensor

There is a risk that toxic heavy metals are released from dental amalgams. This study has demonstrated a sensitive and selective biosensor based on surface-enhanced Raman scattering (SERS), which is capable of measuring mercury(II) ions in human saliva from ppt up to ppb level.  In the biosensor system, the SERS probe and the solid-state chip were functionalized with complementary single-stranded DNA, respectively, except for three artificially designed T-T mismatches. Only in the presence of mercury ions can the SERS probe be captured by the chip due to hybridization of ssDNA, rendering the specific detection of mercury ions. Finite Difference Time Domain (FDTD) simulations have showed that the excellent performance of the SERS biosensor is attributed to the strong coupling between SERS probe and the chip with a high enhancement factor.