Microfluidic technology harnessed to enable multiplexed diagnosis of viral infectious diseases

The unique features of microfluidic diagnostics chips such as modularity, portability, low reagent and sample consumption, and high sensitivity make these microchips suitable for point of care applications. In this week’s research highlight, we will introduce a microfluidic chip that is capable of multiplexed diagnosis of viral diseases using loop-mediated isothermal amplification (LAMP). 

“In this study, we introduce polydimethylsiloxane (PDMS)-based microfluidic devices capable of sequential dispensing of samples into multiple reaction microchambers in a single operation to provide a fast and easy sample-to-answer platform for multiplexed genetic diagnosis of multiple viral infectious diseases. This approach utilizes the loop-mediated isothermal amplification (LAMP) method to amplify and detect specific nucleic acid (DNA/RNA) targets. We present a microfluidic flow control theory for sequential liquid dispensing phenomena, which provides design guidelines for device optimization. “, the authors explained.

The working mechanism of the microfluidic device

The microfluidic chip proposed for multiplex LAMP-based diagnosis of viral infections consists of a mixing region followed by a dispensing region. The microfluidic device is approximately 200 μm in width and 50 μm in height and made with a modified lithography technique. The microchannels were microfabricated using photolithography. However, hemispherical beads (2 mm diameter and 1 mm depth) were glued at the center of the reaction chambers to create deep localized microchambers. 

“We successfully demonstrated that the fabricated microfluidic devices enable the simultaneous diagnosis of COVID-19 (200 copies per μL) and other infectious diseases, such as SARS, seasonal influenza A, and pandemic influenza A (H1N1) 2009, which can be detected using the hue-based quantitative analysis, and the naked eye after running the colorimetric RT-LAMP assay for 30 min. In future studies, considering the ‘life with corona’ era, we will further develop a platform for a fast and easy sample-to-answer simultaneous diagnosis of multiple COVID-19 variants and other infectious diseases (e.g., influenza viruses A and B). “, the authors concluded.

Figures are reproduced from D. Natsuhara, R. Saito, H. Aonuma, T. Sakurai, S. Okamoto, M. Nagai, H. Kanuka and T. Shibata, Lab Chip, 2021, Advance Article , DOI: 10.1039/D1LC00829C under Creative Commons Attribution 4.0 International License

Read the original article: A method of sequential liquid dispensing for the multiplexed genetic diagnosis of viral infections in a microfluidic device