title: Microwave-assisted rapid synthesis of luminescent gold nanoclusters for sensing Hg2+ in living cells using fluorescence imaging.
abstract: A microwave-assisted strategy for synthesizing dihydrolipoic acid (DHLA) capped fluorescent gold nanoclusters (AuNCs) has been developed. Irradiation with microwaves during synthesis enhanced the fluorescence quantum yield (QY) of AuNCs by about five-fold and shortened the reaction time from hours to several minutes. The as-synthesized DHLA-AuNCs possessed bright near-infrared fluorescence (QY: 2.9%), ultrasmall hydrodynamic diameter (3.3 nm), good colloidal stability over the physiologically relevant pH range of 5-10 as well as low cytotoxicity toward HeLa cells. Moreover, these DHLA-AuNCs were capable of sensing Hg(2+) through the specific interaction between Hg(2+) and Au(+) on the surface of AuNCs; the limit of detection (LOD) was 0.5 nM. A potential application in imaging intracellular Hg(2+) in HeLa cells was demonstrated by using spinning disc confocal microscopy.
authors.affiliation: Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology, Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany.
authors.forename: Li
authors.initials: L
authors.lastname: Shang
authors.forename: Linxiao
authors.initials: L
authors.lastname: Yang
authors.forename: Florian
authors.initials: F
authors.lastname: Stockmar
authors.forename: Radian
authors.initials: R
authors.lastname: Popescu
authors.forename: Vanessa
authors.initials: V
authors.lastname: Trouillet
authors.forename: Michael
authors.initials: M
authors.lastname: Bruns
authors.forename: Dagmar
authors.initials: D
authors.lastname: Gerthsen
authors.forename: G Ulrich
authors.initials: GU
authors.lastname: Nienhaus
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D007477:Ions / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D018613:Microscopy, Confocal; D008872:Microwaves; D008063:Thioctic Acid / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D007477:Ions; D008063:Thioctic Acid; D006046:Gold; C015144:dihydrolipoic acid; D008628:Mercury