Figure 6

Alternative colorimetric detection based on the complex murexide-zinc. (A) A strong color change from yellow to pink is observed when pyrophosphate (PPi) is added to a solution containing Zn-MX. Tenfold dilutions of in vitro transcribed (IVT) viral IVT RNA (Ngene) were amplified via RT-LAMP and detected using phenol red (B) or Zn-MX (C). Amplification was confirmed by agarose gel electrophoresis (AGE). Saliva samples of a healthy donor (HD) and of nine COVID-19 patients were analyzed by RT-LAMP followed by detection with Zn-MX (D) or phenol red (E) and amplification was confirmed by AGE (Original gel images in Fig. S1).