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: A G-quadruplex based label-free fluorescent biosensor for lead ion.
    Author: Guo L, Nie D, Qiu C, Zheng Q, Wu H, Ye P, Hao Y, Fu F, Chen G.
    Journal: Biosens Bioelectron; 2012 May 15; 35(1):123-127. PubMed ID: 22417873.
    Abstract:
    Many Pb(2+) biosensors based on Pb(2+)-specific RNA-cleaving DNAzyme have been developed in the past years. However, many of them have limited practical use because of high cost (e.g., enzymes), complicated processing and the use of unstable molecules (e.g., RNA). In this study, a novel label-free fluorescent biosensor for Pb(2+) was proposed based on Pb(2+)-induced allosteric G-quadruplex (PS2.M). In the presence of K(+), N-methyl mesoporphyrin IX (NMM) could bind to K(+)-stabilized G-quadruplexes, giving rise to high fluorescence. On addition of Pb(2+), Pb(2+) competitively binded to K(+)-stabilized G-quadruplexes to form more compact DNA folds. The Pb(2+)-stabilized G-quadruplexes did not bind to NMM, which resulted in fluorescence decrease. This allowed us to utilize PS2.M for quantitative analysis of Pb(2+) using the NMM-G-quadruplex system by convenient "mix-and-detect" protocol. The fluorescence emission ratio (F(0)/F) showed a good linear response toward Pb(2+) over the range from 5.0 nM to 1.0 μM with a limit of detection of 1.0 nM. This proposed biosensor was simple and cost efficiency in design and in operation with high sensitivity and selectivity. We validated the practicality of this biosensor for the determination of Pb(2+) in lake water samples.
    [Abstract] [Full Text] [Related] [New Search]