A sample-to-answer labdisc platform integrated novel membrane-resistance valves for detection of highly pathogenic avian influenza viruses

This work described a novel labdisc platform adopting membrane-resistance (MembR) valves for fully automated sample-to-answer detection of highly pathogenic avian influenza viruses (HPAIVs). The MembR valves as the passive valves were successfully developed by utilizing different hydrophobic or hydrophilic polycarbonate membranes with superfine pore sizes and used in experiments. It allowed a large range of effective rotational speed for fluid control on the disc from 500 to 4750 rpm. In the platform, six MembR valves enabled effective pre-storage and manipulation of RNA extraction reagents under five different rotational speeds. With the help of MembR valves, all the processes for molecular diagnosis including sample lysis, RNA extraction and purification, and specific RNA detection using real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) were integrated on the single disc. We demonstrated that samples of three HPAIVs H7N3, H7N9, and H9N2 and two other influenza A subtypes H1N1 and H3N2 can be automatically analyzed on the centrifugal disc within 70 min. All experiments were applied in a 4 kg portable, laptop controlled point-of-care device. Furthermore, the platform provided a closed non-contact heating with accurate temperature control for POCT nucleic acid diagnosis.