Amplification-Free DNA Detection Using a Microtip-Sensor Decorated With LNA Probes for Rapid TB Screening

Tuberculosis (TB) is an epidemic affecting one-third of the world’s population, mostly in developing and low-resource settings. People having active pulmonary TB are considered highly infectious; therefore, it is critical to identify and treat these patients rapidly before spreading to others. However, the most reliable TB diagnostic methods of bacterial culture or nucleic acid amplification are time-consuming and expensive. The challenge of TB diagnosis lies in highly sensitive and specific screening with low cost. Here, we present an LNA-modified microtip-sensor, which is capable of selectively detecting low-abundance DNA from bacteria. When genomic DNA of Bacillus Calmette-Gue´rin (BCG, a surrogate marker of Mycobacterium bovis), and genomic DNA of Staphylococcus epidermidis (S. epi) are used, the microtip-sensor yields the detection limit of 1,000 copies/mL within 20 minutes. The high sensitivity and specificity approaching nucleic acid amplification methods can potentially overcome the current challenges for rapid TB screening.