An integrated microfluidic loop-mediated-isothermal-amplification system for rapid sample pre-treatment and detection of viruses

This study presents a novel automatic assay for targeted ribonucleic acid (RNA) extraction and a one-step reverse transcription loop-mediated-isothermal-amplification (RT-LAMP) process for the rapid detection of viruses from tissue samples by utilizing an integrated microfluidic system. By utilizing specific probe-conjugated magnetic beads, target RNA samples can be specifically recognized and hybridized onto the surface of the magnetic beads which are mixed with whole tissue lysates, followed by the synthesis of complementary deoxyribonucleic acid (cDNA) and isothermal amplification of target genes simultaneously with the incorporation of two specific primer sets. The nervous necrosis virus (NNV), the most common aquaculture pathogen, with a mortality rate in infected fish ranging from 80% to 100%, has been selected to verify the performance of the developed miniature system. Experimental results showed that the sensitivity of the integrated microfluidic LAMP system is about 100-fold higher when compared to a conventional one-step reverse-transcript polymerase chain reaction (RT-PCR) process. Significantly, the entire protocol from sample pre-treatment to target gene amplification can be completed within 60 min in an automatic manner without cross-reactions with other tested virus, bacteria and eukaryotic cells. Consequently, this integrated microfluidic LAMP system may provide a powerful platform for rapid purification and detection of virus samples.