Scientific Publications by FDA Staff

Clin Vaccine Immunol 2009 Mar;16(3):408-13

Detection of anthrax toxin by an ultrasensitive immunoassay using europium nanoparticles.

Tang S, Moayeri M, Chen Z, Harma H, Zhao J, Hu H, Purcell RH, Leppla SH, Hewlett IK

We developed a europium nanoparticle-based immunoassay (ENIA) for sensitive detection of anthrax protective antigen (PA). ENIA exhibited a linear dose-dependent pattern within the detection range of 0.01 approximately 100 ng/ml and was approximately 100-fold more sensitive than ELISA. False positive results were not observed in normal serum samples, mouse plasma without PA, or plasma samples collected from mice injected with anthrax lethal factor (LF) or edema factor (EF) alone. For detection of plasma samples spiked with PA, the detection sensitivity for ENIA and ELISA was 100% (11/11) and 36.4% (4/11), respectively. The assay exhibits a linear, but qualitative, correlation between PA injected and detected in murine blood (r = 0.9773l, p < 0.0001). Anthrax PA was also detected in circulation of mice infected with spores from a toxigenic Sterne-like strain of Bacillus anthracis but only in the later stages of infection. These results indicate that the universal labeling technology based on europium nanoparticles and its application may provide a rapid and sensitive testing platform for clinical diagnosis and laboratory research.