A new paradigm in tuberculosis diagnostics: Biosensing advances for early detection of Mycobacterium tuberculosis

Tuberculosis (TB) remains one of the most serious and deadly infectious diseases worldwide. Despite being preventable and curable, it is responsible for increasing the annual fatality by millions. The situation is even more alarming in the developing nations, where TB ranked in the top 10 in terms of global mortality. Mycobacterium tuberculosis is the causal pathogen for tuberculosis. It is an extremely resilient bacterium that eludes the immunity of the host and prevails in latent forms. Several biomarkers, including antigens (CFP-10, ESAT-6), antibodies, and nucleic acids, have been identified for their rapid and accurate detection. Conventional screening approaches like culture, chest X-ray, sputum smear microscopy, and PCR-based assays are widely used. However, these approaches suffer from various shortcomings, viz., less sensitivity, delayed diagnosis, potential false negatives, requirement of biosafety infrastructure, and skilled personnel. These diagnostic challenges are resolved by biosensors as they are quick, sensitive, and resource-efficient alternatives to conventional methods. This review comprehensively discusses the pathogenicity of TB as well as conventional approaches for its diagnosis. Further, we have also provided an in-depth analysis of recently reported biosensors for TB detection and critically evaluated their analytical performance.