On-chip analysis of respiratory viruses from nasopharyngeal samples

Point-of-care (PoC) testing followed by personalized efficient therapy of infectious diseases may result in a considerable reduction of associated health care costs. Lab-on-a-chip (LoC) systems represent a potentially high efficient class of PoC tools. Here, we present a LoC system for automated pathogen analysis of respiratory viruses from nasopharyngeal specimens. The device prepares total nucleic acids from extracted swab samples using magnetic silica beads. After reverse transcription the co-purified viral RNA is amplified in accordance with the QIAplex multiplex PCR technology. Hybridized to corresponding QIAGEN LiquiChip beads and labelled with streptavidin R-phycoerythrin, the amplified target sequences are finally detected using a QIAGEN LiquiChip200 workstation. All chemicals needed are either stored freeze-dried on the disposable chip or are provided in liquid form in a reagent cartridge for up to 24 runs. Magnetic stir bars for mixing as well as turning valves with metering structures are integrated into the injection-moulded disposable chip. The core of the controlling instrument is a rotating heating bar construction providing fixed temperatures for fast cycling. PCR times of about half an hour (for 30 cycles) could be achieved for 120 μl reactions, making this system the fastest currently available high-volume PCR chip. The functionality of the system was shown by comparing automatically processed nasopharyngeal samples to ones processed manually according to the QIAGEN "ResPlex™ II Panel v2.0" respiratory virus detection kit. A prototype of the present instrument revealed slightly weaker signal intensities with a similar sensitivity in comparison to the commercially available kit and automated nucleic acid preparation devices, even without protocol optimization.