title: Picomolar selective detection of mercuric ion (Hg(2+)) using a functionalized single plasmonic gold nanoparticle.
abstract: 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.
authors.affiliation: School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul, Korea. xinly601@snu.ac.kr
authors.forename: Hyeon Don
authors.initials: HD
authors.lastname: Song
authors.forename: Inhee
authors.initials: I
authors.lastname: Choi
authors.forename: Young In
authors.initials: YI
authors.lastname: Yang
authors.forename: Surin
authors.initials: S
authors.lastname: Hong
authors.forename: Suseung
authors.initials: S
authors.lastname: Lee
authors.forename: Taewook
authors.initials: T
authors.lastname: Kang
authors.forename: Jongheop
authors.initials: J
authors.lastname: Yi
mesh_terms: 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
chemical_list: D003102:Colloids; D012996:Solutions; D006046:Gold; D008628:Mercury