Figure 1
From: Development of robust isothermal RNA amplification assay for lab-free testing of RNA viruses
RICCA (RNA Isothermal Co-Assisted Coupled Amplification) test concept and mechanism. (A) A working flowchart for the rapid, reliable and field-deployable molecular testing of RNA virus with a sample-to-answer period of less than 20 min using a lateral flow device-powered RICCA test. The four simple operation steps are as follows: a 1-min protocol for easy and painless saliva sampling is used for the collection of biological virus samples (step-1) and for the release of viral RNA (step-2). Next, the lysed solution is directly used for one-pot coupled isothermal RNA and DNA amplification reactions at a temperature near 37 °C for 15–30 min (step-3). Qualitative results are visualized by the naked eye using a DNA lateral flow immunochromatographic assay in 3 min (step 4). (B) Schematics of the mechanism and the key steps involved in the RICCA assay to overcome the inevitable challenging features of conventional isothermal amplification methods.
