title: Visual detection of Hg²⁺ in aqueous solution using gold nanoparticles and thymine-rich hairpin DNA probes.
abstract: We report a sensitive method for visual detection of mercury ions (II) (Hg²⁺) in aqueous solution by using gold nanoparticles (Au-NPs) and thymine (T)-rich hairpin DNA probes. The thiolated hairpin DNA probe was immobilized on the Au-NP surface through a self-assembling method. Another thymine-rich, digoxin-labeled DNA probe was introduced to form DNA duplexes on the Au-NP surface with thymine-Hg²⁺-thymine (T-Hg²⁺-T) coordination in the presence of Hg²⁺. The Au-NPs associated with the formed duplexes were captured on the test zone of a lateral flow strip biocomponent (LFSB) by immunoreaction events between the digoxin on the duplexes and anti-digoxin antibodies on the LFSB. The accumulation of Au-NPs produced a characteristic red band on the test zone, enabling visual detection of Hg²⁺ without instrumentation. A detection limit of 0.1 nM was obtained under optimal experimental conditions. This method provides a simple, rapid, sensitive approach for the detection of Hg²⁺ and shows great promise for point-of-care and in-field detection of environmentally toxic mercury.
authors.affiliation: Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou 510095, China. dr.hyq@hotmail.com
authors.forename: Yuqing
authors.initials: Y
authors.lastname: He
authors.forename: Xibao
authors.initials: X
authors.lastname: Zhang
authors.forename: Kang
authors.initials: K
authors.lastname: Zeng
authors.forename: Sanquan
authors.initials: S
authors.lastname: Zhang
authors.forename: Meenu
authors.initials: M
authors.lastname: Baloda
authors.forename: Anant S
authors.initials: AS
authors.lastname: Gurung
authors.forename: Guodong
authors.initials: G
authors.lastname: Liu
mesh_terms: D055910:Antibodies, Immobilized; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D004077:Digoxin / Q000276:immunology; D006046:Gold; D057230:Limit of Detection; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles; D058726:Nanoconjugates; D013941:Thymine / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D055910:Antibodies, Immobilized; D015342:DNA Probes; D058726:Nanoconjugates; D014874:Water Pollutants, Chemical; D004077:Digoxin; D006046:Gold; D008628:Mercury; D013941:Thymine