Tuberculosis Diagnostics Using a Nanotip Sensor

Tuberculosis (TB) is one of the most widely spread diseases. In 2006, 9.2 million new TB cases were reported with 1.7 million victims [1]. To diagnose TB, Mycobacterium tuberculosis (MTB) is identified in clinical samples. The challenge of TB diagnostics is high-performance screening conducted by nontrained personnel. Currently, nucleic acid testing with target-amplification strategy such as polymerase chain reaction (PCR) is available for detection of TB. However, this entails cumbersome procedures run by skilled operators with expensive instrumentation and reagents. To overcome these challenges, this paper presents a nanotip sensor to diagnose TB rapidly without target-amplification. The proposed methodology uses a nanostructured tip as a biosensor to detect target analytes. The novelty of this approach is in the superior concentration and detection mechanisms of nucleic acids on the terminal end of a nanotip using an alternating current (AC) electric field, specific chemical binding, and capillary action. Confirmatory identification of MTB is achieved by detecting MTB strains on a nanostructured tip through DNA hybridization. In this paper, the working principle is presented with the demonstration of amplification-free detection of MTB genomic DNA using the nanotip sensor. The performance of the tip sensor is characterized.