Detection of hepatitis B surface antigen using time-resolved fluoroimmunoassay

Area of Science:

• Biochemistry
• Analytical Chemistry
• Immunology

Background:

• Conventional fluoroimmunoassays (FIA) lack the sensitivity of radioimmunoassays (RIA) due to background fluorescence.
• Biological specimens often contribute to high background fluorescence in traditional FIA methods.

Purpose of the Study:

• To develop a highly sensitive immunoassay for hepatitis B surface antigen (HBsAg).
• To overcome the limitations of conventional FIA by reducing background fluorescence.

Main Methods:

• Utilized time-resolved fluorescence (TRF) with lanthanide labels for HBsAg detection.
• Employed a delay time measurement to eliminate fast-decaying background fluorescence.
• Used chelates of rare earth metals (e.g., Eu, Tb) with long fluorescent lifetimes and a long Stokes' shift (>270 nm).
• Optimized chelation using 2-naphthoyltrifluoroacetone and synergistic agents like trioctylphosphineoxide.

Main Results:

• Achieved highly sensitive detection of lanthanides at concentrations of 10(-12)-10(-14)M.
• Demonstrated the potential for a new generation of immunoassays with significantly reduced background interference.
• Successfully developed a TR-FIA for HBsAg detection.

Conclusions:

• Time-resolved fluorescence immunoassays offer superior sensitivity compared to conventional FIA by minimizing background noise.
• Lanthanide chelates provide a robust platform for highly sensitive biomarker detection.
• This TR-FIA method represents a significant advancement in immunoassay technology for diagnostics.