Detection of Mycobacterium tuberculosis Using a Capillary-Array Microsystem with Integrated DNA Extraction, Loop-Mediated Isothermal Amplification, and Fluorescence Detection

This article reports for the first time a high-throughput microfluidic system with fully integrated loop-mediated isothermal amplification (LAMP) analysis. With the developed system, parallel Mycobacterium tuberculosis detections were implemented in polytetrafluoroethylene capillaries through the utilization of droplet technology coupled with magnetic beads. During the analysis, liquid plugs containing different types of sample or reagents are sequentially introduced into the capillaries and made to form droplets therein. The whole analytical process, including DNA extraction, LAMP, and detection of the amplified products were conducted in such droplets. The developed microsystem is able to process 10 samples in parallel. The entire diagnostic procedure, from sample-in to answer-out, can be automatically completed within 50 min with a limit of detection (LOD) of 10 bacteria. This microsystem was evaluated by analyzing clinical samples, and a clinical sensitivity (positive detection rate) of 96.8% and specificity (negative detection rate) of 100% were achieved. The presented capillary LAMP assay features high-throughput and low-cost and thus is a promising tool for rapid tuberculosis diagnosis.