Tuberculosis (TB) is an ancient disease constituted a long-term menace to public health. According to World Health
Organization (WHO), mycobacterium tuberculosis (MTB) infected nearly a third of people of the world. There is about
one new TB occurrence every second. Interferon-gamma (IFN-γ) is associated with susceptibility to TB, and interferongamma
release assays (IGRA) is considered to be the best alternative of tuberculin skin test (TST) for diagnosis of latent
tuberculosis infection (LTBI). Although significant progress has been made with regard to the design of enzyme
immunoassays for IFN-γ, adopting this assay is still labor-intensive and time-consuming. To alleviate these drawbacks,
we used IFN-γ antibody to facilitate the detection of IFN-γ.
An experimental verification on the performance of IGRA was done in this research. We developed two biosensor
configurations, both of which possess high sensitivity, specificity, and rapid IFN-γ diagnoses. The first is the
electrochemical method. The second is a circular polarization interferometry configuration, which incorporates two light
beams with p-polarization and s-polarization states individually along a common path, a four photo-detector quadrature
configuration to arrive at a phase modulated ellipsometer. With these two methods, interaction between IFN-γ antibody
and IFN-γ were explored and presented in detail.