These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effects of Mn2+ on oligonucleotide-gold nanoparticle hybrids for colorimetric sensing of Hg2+: improving colorimetric sensitivity and accelerating color change.
    Author: Yu CJ, Cheng TL, Tseng WL.
    Journal: Biosens Bioelectron; 2009 Sep 15; 25(1):204-10. PubMed ID: 19631521.
    Abstract:
    In this paper, we present a simple and rapid colorimetric assay--using the polythymine oligonucleotide T(33), citrate-capped gold nanoparticles (AuNPs), and phosphate-buffer saline (PBS) in the presence of Mn(2+)--for the highly selective and sensitive detection of Hg(2+) in an aqueous solution. Citrate-capped AuNPs adsorbed on randomly coiled T(33) were dispersed well in PBS because of strong electrostatic repulsion between DNA molecules. In the presence of Hg(2+), the formation of Hg(2+)-T(33) complexes enabled the removal of T(33) molecules from the NP surface, resulting in salt-induced NP aggregation. However, the T(33)-capped AuNPs (T(33)-AuNPs) were dispersed in PBS solution after the addition of 1.0 microM Hg(2+), indicating that T(33)-AuNPs had poor colorimetric sensitivity toward Hg(2+). We uncovered that the addition of Mn(2+) to a solution containing 0.75 nM T(33)-AuNPs and 0.2x PBS resulted in an acceleration of the analysis time (within 5 min) and a 100-fold sensitivity improvement for the detection of Hg(2+). As a result, the present approach enables the analysis of Hg(2+) with a minimum detectable concentration that corresponds to 10 nM. This is probably attributed to that Mn(2+) binds strongly to the phosphate backbone of DNA, thereby accelerating Hg(2+)-induced aggregation of the T(33)-AuNPs. Because Mn(2+) can stabilize the folded structure of the Hg(2+)-T(33) complex, Hg(2+) facilitates the removal of T(33) from the NP surface in the presence of Mn(2+). This probe was successfully applied to the determination of Hg(2+) in pond water.
    [Abstract] [Full Text] [Related] [New Search]