Current methods in use to detect the novel coronavirus that causes COVID-19 include techniques based on the polymerase chain reaction (PCR). These methods are hampered by limited precision and by the need for expensive laboratory equipment.
Kathrada et al. review recent research in microfluidics that could lead to improved detection of COVID-19 infections as well as other infectious diseases, such as flu and tuberculosis.
Three types of microfluidic approaches are considered in this review: microwell-based PCR platforms; droplet-based PCR; and point-of-care (PoC) devices. The latter include disc microfluidics; SlipChip devices; and self-powered integrated microfluidic point-of-care low-cost enabling (SIMPLE) chips. All of these PoC devices could, potentially, be used at home.
Detecting infection relies on the measurement of specific substances in blood or other samples, such as proteins, DNA and RNA. Sensitivity is limited by low concentration of these substances, which can occur early in an infection. Microfluidics is attractive, because the small sample volumes greatly increase analyte concentration.
PoC devices based on microfluidic technology that could potentially be used in the home are of particular interest to researchers in the field. “There are, however, considerable challenges to be faced before PoC devices become routine,” author Chia-Hung Chen said. “For instance, although most microfluidic chips are small, the whole system containing the optical components are bulky and not suitable for PoC applications.”
One particular PoC device reviewed by the authors, the SIMPLE Chip design, contains small reaction chambers of about 100 nanoliter volume, capable of directly detecting gene biomarkers in bloods. Air is used to drive the flow of fluids through the device, avoiding the need to use large pumps or control components.
Source: “Microfluidic compartmentalization to identify gene biomarkers of infection,” by Ahmad Ismat Kathrada, Shih-Chung Wei, Ying Xu, Lih Feng Cheow, and Chia-Hung Chen, Biomicrofluidics (2020) The article can be accessed at https://doi.org/10.1063/5.0032849.