Update on the Development of Toehold Switch-Based Approach for Molecular Diagnostic Tests of COVID-19

Figure 2

General scheme of the currently developed toehold switch-based diagnostics for COVID-19: (a) a system developed by Chakravarthy et al. [40] which utilized NASBA (nucleic acid sequence-based amplification) for amplifying trigger RNA from patient’s nasopharyngeal swab sample and toehold switch-based biosensor with lacZ as a reporter gene, (b) a system developed by Köksaldl et al. [41] which utilized NASBA for amplifying trigger RNA from patient’s nasopharyngeal swab sample and toehold switch-based biosensor with superfolder GFP as a reporter gene, (c) a system developed by Park et al. [42] which utilized reverse transcription loop-mediated amplification (RT-LAMP) for amplifying trigger RNA from patient’s saliva sample and toehold switch-based biosensor with lacZ as a reporter gene, and (d) a trigger RNA amplification-free system developed by Hunt et al. [43] which detected SARS-CoV-2 RNA from patient’s saliva sample using toehold switch-based biosensor with NanoLuc as a reporter gene.

(a)

(b)

(c)

(d)