Article

Functionalized fluorescent gold nanodots: synthesis and application for Pb2+ sensing.

College of Chemistry and Chemical Engineering, State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha, PR China.
Chemical Communications (Impact Factor: 6.38). 09/2011; 47(43):11981-3. DOI: 10.1039/c1cc14872a
Source: PubMed

ABSTRACT We developed a novel strategy to prepare functionalized fluorescent gold nanodots (AuNDs) based on a ligand exchange reaction and demonstrated that glutathione modified AuNDs can be utilized for highly sensitive and selective Pb(2+) sensing in aqueous solution.

0 Bookmarks
 · 
213 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Specific and homogeneous detection of heavy metal ion is of great importance for both human health care and environmental protection. We reported a highly specific and sensitive assay for fluorescent detection of Pb(2+) based on the difference in quenching ability between deoxyguanosines and G-quartet by using carboxyfluorescein-labeled hairpin DNA (F-hpDNA) as a recognition probe. In the absence of target, the fluorescence of F-hpDNA can be quenched through photoinduced electron transfer from the dye to deoxyguanosines because the formation of hairpin brings deoxyguanosines close to the FAM. In the presence of Pb(2+), the formation of G-quadruplex DNA leads to a significant decrease in fluorescence due to the effective stack of dye on the G-quartet, which obviously intensified the quenching of fluorophore. In comparison with linear DNA probe, hairpin DNA probe greatly improved the specificity, and Pb(2+) can be highly selective detected even when coexisted with other metal ions. The quenching efficiency is linear with the concentration of lead(II) over the range of 0.5-500nM, with a limit of detection of 0.4nM. Conformational switch from hairpin to G-quadruplex was verified by CD measurements. Moreover, the application for detection of real samples further demonstrated its reliability. Therefore, it is a selective, simple and sensitive approach for detection of lead ion, as such, it promises to provide a solid foundation for developing universal analytical method for heavy metal ions.
    Biosensors & Bioelectronics 08/2012; · 6.45 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We synthesized green-emitting platinum (Pt) nanoclusters (excitation: 460 nm, emission: 520 nm) by reducing Pt ions from pre-equilibrated Pt/fourth-generation poly(amidoamine) dendrimers (PAMAM (G4-OH)) complexes with a mild reductant. The structural characteristics of the resulting Pt nanoclusters, Pt 8 L 8 (L = C 2 H 2 O 2 S), were determined by Electrospray ionization (ESI) mass spectroscopy. These nanoclusters possess a 28% quantum yield, which is higher than those of green-emitting Au and Ag nanoclusters. We also found that Pt nanoclusters have considerably low cytotoxicity and biocompatibility, and demonstrated that they could be used for biomedical imaging. This study provides the possibility to extend the photoluminescent wavelength of Pt nanoclusters to the near infrared region, which is ideal for biological imaging applications.
    Optical Materials Express 02/2013; 3(2):157-165. · 2.92 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A colorimetric assay based on silver nanoparticles (NAC-Ag NPs) capped with N-acetyl-l-cysteine (C5H9NO3S, NAC) has been developed which exhibits highly selectivity towards Ni2+ over other cations such as Al3+, Cr3+, Fe3+, Co2+, Pb2+, Ba2+, Cd2+, Fe2+, Cu2+, Hg2+, Zn2+, Mn2+, Ag+, Mg2+, Ca2+, Na+, and K+ under specified conditions. Silver nanoparticles were prepared by reducing AgNO3 with sodium borohydride (NaBH4) in the presence of NAC. The infrared spectra suggested that NAC was successfully capped on the surface of the silver nanoparticles. In the presence of Ni2+, rapid aggregation of NAC-Ag NPs was induced along with color change from yellow to deep orange. The absorbance ratio (A 550/A 390) was linear with the concentration of Ni2+ in the wide range from 2 to 48 μM with a detection limit of 0.23 μM. The proposed method was applied successfully to the determination of Ni2+ in tap water samples, and the recoveries were from 92 to 106 %.
    Journal of Nanoparticle Research 14(10). · 2.18 Impact Factor