In this work, we demonstrate a novel rotary microsystem for simple, rapid and automatic
influenza viral RNA purification. The microdevice consists of a
silica sol-gel matrix for
RNA capture, and three reservoirs for a
RNA sample (R(S)), a washing
solution (R(W)) and an elution
buffer (R(E)) that were connected with different dimensional microfluidic channels (120 μm for R(S), 40 μm for R(W), and 20 μm for R(E)). The hydrophobic property of PDMS and the narrow microchannel served as a passive capillary microvalve, and the loading of the solutions were controlled by centrifugal force. 5 μL of a lysate sample of
influenza A H1N1 virus, a washing
solution and an elution
buffer were injected in each designated reservoir, and the virus sample, the washing
solution, and the elution
buffer were sequentially loaded into the
sol-gel chamber at 1600, 2000, and 2500 RPM, enabling the
viral RNA to be captured in the
sol-gel solid phase, purified, and eluted in 5 min. The
RNA capture yield was measured as ~80%, and the H1 and M gene were successfully amplified from the recovered purified H1N1
viral RNA by
reverse-transcriptase PCR. Such a novel rotary sample preparation system eliminates any complicated hardware and human intervention, and performs the
RNA extraction with high speed and high fidelity.