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: Immunoliposome sandwich assay for the detection of Escherichia coli O157:H7.
    Author: Park S, Durst RA.
    Journal: Anal Biochem; 2000 Apr 10; 280(1):151-8. PubMed ID: 10805533.
    Abstract:
    We describe the development of a field-portable colorimetric immunoassay for the detection of Escherichia coli O157:H7, using antibody-directed liposomes (immunoliposomes) encapsulating dye as an analytical reagent. Antibodies (anti-E. coli O157:H7) thiolated by 2-iminothiolane were coupled to malemide-tagged liposomes encapsulating the marker dye, sulforhodamine B. Transmission electron microscopy showed that the immunoliposomes bound only to the serotype without any cross-reactivity with tested negative controls. A wicking reagent containing immunoliposomes and the test sample and a plastic-backed nitrocellulose strip with a measurement zone were used in a sandwich (noncompetitive) assay format. During the capillary migration of the wicking reagent, E. coli, with surface-bound immunoliposomes, was captured at the measurement zone on which antibodies to E. coli O157:H7 were immobilized. The color density of the measurement zone was directly proportional to the amount of E. coli O157:H7 in the sample. The detection limit of the current assay with pure cultures of the serotype was ca. 10(4) colony-forming units (CFU)/mL. The assay, which does not need washing and incubation steps, can be completed in 8 min. These results demonstrate the feasibility of using dye-encapsulating immunoliposomes in microporous membranes for the rapid detection of molecules with multivalent antigenic sites.
    [Abstract] [Full Text] [Related] [New Search]