An integrated microfluidic system for diagnosis and multiple subtyping of influenza virus

This study presents an integrated microfluidic system capable of rapid diagnosis and subtyping of influenza virus. Several critical modules including a ribonucleic acid (RNA) extraction module, a reverse-transcription polymerase chain reaction (RT-PCR) module and an optical detection module were integrated into the microsystem. Magnetic beads conjugated with specific nucleotide probes were first incubated with influenza virus. Then thermolysis and hybridization processes were performed to extract target RNA by utilizing a magnetic field. Then, extracted viral RNA can be specifically amplified by using a one-step RT-PCR process. Finally, amplified RT-PCR products were detected using the optical detection module. The entire process can be completed within less than 2 hour. Moreover, the detection limit of the microsystem was experimentally found to be 10⁴~10⁵ dilution of 128 HAU of influenza virus for influenza A virus H1 subtype. Consequently, the proposed integrated microfluidic system can provide a powerful platform for rapid diagnosis of influenza infection. Experimental results also showed that different subtypes of influenza virus could be diagnosed by using a multiple RT-PCR process. This one-step multiple RT-PCR performed on the integrated microfluidic system may provide a promising tool for fast screening of seasonal and novel influenza virus.