Liquid crystal-based aptasensor for the detection of interferon-gamma and its application in the diagnosis of tuberculosis using human blood

Abstract

We report the development of a liquid crystal (LC)-based aptasensor for the detection of interferon-gamma (IFN-gamma) in human blood as well as the diagnosis of tuberculosis (TB). In this system, the binding of IFN-gamma to an aptamer immobilized on a surface disrupts the orientation of LCs, inducing a transition from a homeotropic orientation to a random one. This change in the orientation of the LCs can easily be converted and observed as a shift from a dark optical LC image to a bright one under a polarized light microscope. Through this sensing mechanism, IFN-gamma levels as low as 1 pM (17 pg/ml) could be detected. This LC-based aptasensor was employed for the diagnosis of TB using blood samples from patients with latent TB. With this LC-based approach, not only could IFN-gamma readily be detected, but also latent TB could be diagnosed using human blood simply and effectively without any intricate processes or instrumentation. Therefore, our present research provides a promising IFN-gamma sensor with applications in clinical diagnosis of various infectious diseases, and in immunological research.