A Fiber-optic Sensor Based on Plasmon Coupling Effects in Gold Nanoparticles Core-satellites Nanostructure for Determination of Mercury Ions (II)

Based on the plasmon coupling effect in gold nanoparticles core-satellites nanostructure linked by thymine(T)-rich DNA hybridization and the specific Hg2+-mediated T-Hg2+-T base pair, a novel localized surface plasmon resonance (LSPR) optical fiber sensor was proposed and developed for Hg2+ detection in water samples. The Hg2+-induced conformational change in T-rich DNA sequence inhibited the DNA hybridization reaction, weakened the plasmon coupling effect and leaded to the change of LSPR resonance wavelength. The concentration of Hg2+ was quantitatively determined by the resonance wavelength redshift. The linear range of Hg2+ detection was about 5–150 nM with LOD of 3.4 nM. The specificity of the sensor was proved great by evaluating the response to other heavy metal ions such as Zn2+, Mg2+, Pb2+ and so on. This sensor was applied in environmental water detection by standard addition method, with the RSD less than 4.79 % and recoveries from 94.2% to 105.4%.