Janus-Type Immunofluorescent Probes and a Quantitative Immunoassay System.

Area of Science:

• Biotechnology
• Immunodiagnostics
• Nanotechnology

Background:

• Highly sensitive immunoassays require probes with high optical density to enhance antigen-antibody complex visibility.
• Current methods face challenges in sensitivity and specificity for detecting viral antigens.

Purpose of the Study:

• To develop a novel immunoassay system utilizing magnetic and fluorescent Janus particles.
• To improve the sensitivity and reliability of detecting viral antigens, specifically SARS-CoV-2.

Main Methods:

• Conjugation of antibodies to magnetic and fluorescent Janus particles.
• Integration of Janus particles with an antibody-immobilized microfluidic device.
• Quantification of antigen-antibody complex formation via fluorescence detection.

Main Results:

• Achieved a detection limit of 3.1 ng/mL for differentiating SARS-CoV-2 from human coronavirus 229E.
• Demonstrated high signal stability with a standard deviation of less than 5%.
• Validated the efficacy of Janus particles as probes in a microfluidic immunoassay.

Conclusions:

• The developed immunofluorescent probe and immunoassay system offer high sensitivity and stability.
• This system is adaptable for the quantitative measurement of various disease markers beyond SARS-CoV-2.
• The Janus particle-based approach advances microfluidic immunoassay technology for diagnostics.