A rapid DNA biosensor for the molecular diagnosis of infectious disease

Treating patients with infectious diseases relies heavily on rapid and proper diagnosis. Molecular detection such as PCR has become increasingly important and efforts have been made to simplify these detection methods. This study reports the development of a glass fibre-based lateral flow DNA biosensor that uses capture reagents coupled to carrier beads and detector reagent bioconjugated to gold nanoparticles, for the detection of foodborne pathogen, Vibrio cholerae. The DNA biosensor contains a test line which captures target PCR amplicons, an internal amplification control (IC) line which captures IC amplicons and a control line which acts as membrane control to validate the functionality of this device. The test line captures biotin labelled DNA, while the IC line captures digoxigenin labelled DNA. The detector reagent recognizes the fluorescein haptens of the amplified DNA and produces visual red lines. Scanning electron microscopy (SEM) studies performed indicated that the capture reagents remained relatively immobile within the matrix of the membrane even after binding of the detector reagent. The DNA biosensor recorded a limit of detection (LoD) of 5 ng of target DNA. A clinical evaluation was carried out with 174 strains of V. cholerae and non V. cholerae bacteria and the DNA biosensor recorded 100% for both sensitivity and specificity when compared to conventional agarose gel detection of DNA. Thus it is a viable alternative to agarose gel analysis and is easy-to-use, disposable and do not require any specialized equipment and use of carcinogenic chemicals.