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: Direct, ultrasensitive, and selective optical detection of protein toxins using multivalent interactions.
    Author: Song X, Swanson BI.
    Journal: Anal Chem; 1999 Jun 01; 71(11):2097-107. PubMed ID: 10366891.
    Abstract:
    Three highly sensitive, selective, and reagent-free optical signal transduction methods for detection of polyvalent proteins have been developed by directly coupling distance-dependent fluorescence self-quenching and/or resonant-energy transfer to the protein-receptor binding events. The ganglioside GM1, as the recognition unit for cholera toxin (CT), was covalently labeled with fluorophores and then incorporated into a biomimetic membrane surface. The presence of CT with five binding sites for GM1 causes dramatic change for the fluorescence of the labeled GM1. (1) In the scheme using fluorescence self-quenching as a signal-transduction mechanism, the fluorescence intensity drops significantly as a result of aggregation of the fluorophore-labeled GM1 on a biomimetic surface. (2) By labeling GM1 with a fluorescence energy transfer pair, aggregation of the labeled GM1 results in a decrease in donor fluorescence and an increase in acceptor fluorescence, providing a unique signature for selective protein-receptor binding. (3) In the third scheme, using the biomimetic surface as part of signal transduction and combining both fluorescence self-quenching and energy-transfer mechanisms to enhance the signal transduction, a signal amplification was achieved. The detection systems can reliably detect less than 0.05 nM CT with fast response (less than 5 min). This approach can easily be adapted to any biosensor scheme that relies on multiple receptors or co-receptors. The methods can also be applied to investigate the kinetics and thermodynamics of the multivalent interactions.
    [Abstract] [Full Text] [Related] [New Search]