SERS Detection and Removal of Mercury(II)/Silver(I) using Oligonucleotide-Functionalized Core/Shell Magnetic Silica Sphere@Au Nanoparticles

Abstract

Heavy metal ions, such as Hg(2+) and Ag(+), pose severe risks in human health and the environment. For sensitive detection and selective removal of Hg(2+) and Ag(+) ions, here, we demonstrate a surface-enhanced Raman scattering (SERS)-active platform by employing the oligonucleotide-functionalized magnetic silica sphere (MSS)@Au nanoparticles (NPs). This system exploits mismatched T-Hg-T and C-Ag-C bridges to capture Hg(2+) and Ag(+) ions, exhibiting excellent responses for Hg(2+) ions in the range of 0.1-1000 nM and for Ag(+) in the range of 10-1000 nM. The assay is highly selective for the target ions and does not respond to other metal ions. Additionally, the Hg(2+) and Ag(+) ions in this system can be effectively removed from surrounding solutions by an external magnetic field or through spontaneous precipitation. Moreover, more than 80% of the MSS@Au NPs can be easily recycled with the help of cysteine. We anticipate that the designed strategy could be extended to other analytes that can bind to DNA molecules with a high affinity, and can be used in many potential applications such as environmental renovation, toxin detection, and groundwater analysis.

Fabrication of cube-like Fe3O4@SiO2@Ag nanocomposites with high SERS activity and their application in pesticide detection

“…Since the discovery of (SERS) in 1974 (Fleischmann et al 1974), it has aroused intense interest due to its high sensitivity and specificity in the detection of analytes (Su et al 2012;Liu et al 2014;Han et al 2015). The enormous SERS enhancement effect has enabled this technology to be widely applied in biology, medicine pharmacy, environmental monitoring, national security and other fields over the decades (Ye et al 2012;Zong et al 2012;Yang et al 2014;Wang et al 2014a).…”

Recent progress in detection of mercury using surface enhanced Raman spectroscopy — A review

“…The magnetic substrates could efficiently adsorb the analyte molecules from environmental matrix and can be easily separated and removed from the matrix by a magnet, providing a convenient platform for the sensitive detection and selective removal of Hg 2+ . For example, Liu et al (2014) proposed a SERS-active platform with the oligonucleotide-functionalized magnetic silica sphere (MSS)@ Au NPs (Fig. 8D).…”

Functional nucleic acid-based sensors for heavy metal ion assays

“…[153][154][155][156][157][158][159][160][161][162][163][164][165] Through monitoring the different emission of quantum dots, Freeman et al reported a uorescent sensor for multiplex detection of Hg 2+ and Ag + using nucleic acid-functionalized quantum dots. 161 The detection limit can reach 10 nM for Hg 2+ and 1 mM for Ag + .…”

“…12). 165 In this sensor, MSS@AuNPs are functionalized by two types of ssDNA with different capture segments and two different Raman reporter-labeled ssDNAs, respectively. In the presence of Hg 2+ and Ag + , the T-T mismatch can effectively capture Hg 2+ to form the T-Hg 2+ -T bridges, and the C-C mismatch can effectively capture Ag + to form the C-Ag + -C bridges, enabling the generation of plasmonic hotspots and consequently the enhanced SERS signals.…”