Point-of-care detection of tuberculosis using magnetoresistive biosensing chip.

In this paper, a highly sensitive and specific technique based on the principle of giant magnetoresistance (GMR) has been proposed for the early stage Tuberculosis (TB) diagnostics. This GMR biosensing assay employs monoclonal antibodies against M. tuberculosis specific ESAT-6 antigen with the use of magnetic nanoparticles (MNPs) as labels. MNPs bind to the GMR sensor in presence of ESAT-6 and the binding is proportional to the ESAT-6 protein concentration leading to the change in overall resistance of GMR sensor. GMR biosensor simulation showed that ESAT-6 concentration can be detected in the range of pg/mL in comparison to the other transduction techniques available for ESAT-6 detection and further, the signal strength increased with the increase in the concentration. This work has shown that the GMR biosensing strategy is pertinent for the TB detection at the primitive phases when compared with other magnetic techniques used for TB diagnostics.