Picomolar selective detection of mercuric ion (Hg(2+)) using a functionalized single plasmonic gold nanoparticle.
A highly sensitive method for the selective detection and quantification of mercuric ions (Hg(2+)) using single plasmonic gold nanoparticle (GNP)-based dark-field microspectroscopy (DFMS) is demonstrated. The method is based on the scattering property of a single GNP that is functionalized with thiolated molecules, which is altered when analytes bind to the functionalized GNP. The spectral resolution of the system is 0.26 nm and a linear response to Hg(2+) was found in the dynamic range of 100 pM-10 microM. The method permits Hg(2+) to be detected at the picomolar level, which is a remarkable reduction in the detection limit, considering the currently proscribed Environmental Protection Agency regulation level (10 nM, or 2 ppb) and the detection limits of other optical methods for detecting Hg(2+) (recently approx. 1-10 nM). In addition, Hg(2+) can be sensitively detected in the presence of Cd(2+), Pb(2+), Cu(2+), Zn(2+) and Ni(2+), which do not interfere with the analysis. Based on the findings reported herein, it is likely that single-nanoparticle-based metal ion sensing can be extended to the development of other chemo- and biosensors for the direct detection of specific targets in an intracellular environment as well as in environmental monitoring.
Song
Hyeon Don
HD
School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Korea. xinly601@snu.ac.kr
Choi
Inhee
I
Yang
Young In
YI
Hong
Surin
S
Lee
Suseung
S
Kang
Taewook
T
Yi
Jongheop
J
D000327:Adsorption; D015374:Biosensing Techniques; D003102:Colloids; D006046:Gold / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D055620:Optical Phenomena; D012996:Solutions; D013499:Surface Properties; D013997:Time Factors
D003102:Colloids; D012996:Solutions; D006046:Gold; D008628:Mercury