Ultrasensitive detection of Hg(II) through metal-enhanced fluorescence and hybridization chain reaction

Key Words:Nanoparticle; Fluorescence; Magnetic; Ag@SiO2; Hg2+

Abstract:We report a sensitive sensing strategy based on metal-enhanced fluorescence (MEF) and hybridization chain reaction (HCR). Hg2+ aptamers were immobilized on magnetic nanoparticles (NPs) and HCR process happened without Hg2+, forming long DNA chains and allowing fluorescent indicator (SYBR Green) intercalated in the double helix. After magnetic separation from test solution, positively charged Ag@SiO2 NPs were added, they were electrostatically absorbed on negatively charged DNA chains, acting as "smart dust" to enhance fluorescence signal. This design was used for Hg2+ detection and it showed high sensitivity with a limit of detection down to 25 pM. This method also exhibited good selectivity over other metal ions and was successfully applied in real water sample analyses. (C) 2017 Elsevier B.V. All rights reserved.

Volume:245

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Translation or Not:no