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- Title
A sensitive optical sensor based on DNA-labelled $$\hbox {Si}@\hbox {SiO}_{2}$$ core-shell nanoparticle for the detection of $$\hbox {Hg}^{2+}$$ ions in environmental water samples.
- Authors
Srinivasan, Krishnan; Subramanian, Kathavarayan; Rajasekar, Aruliah; Murugan, Kadarkarai; Benelli, Giovanni; Dinakaran, Kannaiyan
- Abstract
$$\hbox {Si}@\hbox {SiO}_{2}$$ core-shell nanoparticles were proposed for the development of fluorescent mercury sensor, which also offers a promising alternative to toxic quantum dots (QD)-based heavy metal detection tools. In this study, a sensitive fluorescent assay based on DNA-labelled $$\hbox {Si}@\hbox {SiO}_{2}$$ core-shell nanoparticles for the detection of mercury (II) in environmental samples was investigated. Probe DNA was conjugated on the surface of the $$\hbox {Si}@\hbox {SiO}_{2 }$$ core-shell nanoparticles via $$5^{\prime }$$ -terminal-SH (thiol group) reaction. The detection protocol was based on the DNA hybridization resulted from the formation of mercury-mediated (thymine- $$\hbox {Hg}^{2+}$$ -thymine) base pairs which leave a fluorescent QD on the surface of quartz glass. The synthesized $$\hbox {Si}@\hbox {SiO}_{2}$$ core-shell nanoparticle showed a broad emission peak with strong intensity in the UV range around 423 nm. Transmission electronic microscope (TEM) images confirmed the presence of a uniform core-shell structure with Si core nanoparticles with a particle size ranging from 70 to 80 nm and silica shell thickness of about $$10 \pm 2\,\hbox {nm}$$ . Overall, our findings highlighted that the developed assay can detect $$\hbox {Hg}^{2+ }$$ ions in aqueous solution as low as 0.92 nM concentration. In addition, the labelled $$\hbox {Si}@\hbox {SiO}_{2}$$ core-shell nanoparticles showed prominence sensitivity, acceptable precision, reproducibility and stability, and could be readily applied to environmental sampling systems for $$\hbox {Hg}^{2+}$$ monitoring. Graphical Abstract::
- Subjects
NANOPARTICLES; WATER analysis; OPTICAL sensors; QUANTUM dots; FLUORESCENT probes; AQUEOUS solutions; ENVIRONMENTAL sampling
- Publication
Bulletin of Materials Science, 2017, Vol 40, Issue 7, p1455
- ISSN
0250-4707
- Publication type
Article
- DOI
10.1007/s12034-017-1486-x