New microfluidic platform with integrated DNA biosensor for the detection of SARS-CoV-2

In their new publication, Sandrine Gerber's research group at EPF Lausanne presents the potential utility of their microfluid platform with integrated DNA biosensor for the detection of SARS-CoV-2 virus from saliva samples.

The Covid-19 pandemic has highlighted the need for rapid and less resource-intensive test settings that allow large-scale screening of SARS-CoV-2. The research group led by Sandrine Gerber at the EPF in Lausanne has developed a screening device that integrates a DNA embedded into a microfluidic platform. The collected saliva samples circulate through a pre-treatment chamber where SARS-CoV-2 viral RNA is extracted and a screening chamber containing the DNA biosensor for recognition of the viral gene sequence. In case the sample contains SARS-CoV-2, hybridization at the surface of the biosensor is detected by an opto-electronic system which converts the fluorescence emitted by the formed duplex in the presence of SYBR Green into an electrical signal. The biosensor equipped with a functionalized glass slide detects the viral RNA reliably and without the need for amplification. It has a detection limit of 6 viral copies per microliter of saliva sample and provides a result in a few minutes.

This enables rapid testing with high specificity in a non-medical environment such as mobile testing stations. The time required per unit tested is 15 minutes, which allows for almost immediate feedback to those tested. The platform has the potential to become a new standard testing method for low-threshold infection diagnostics directly in the field. It is inexpensive and can be implemented by non-medical personnel, which enables a simpler test setting and can thus be used in developing countries. Furthermore, the method will be useful for future pandemics, as the detection of viruses other than SARS-CoV-2 is possible as well.