SARS-CoV-2 facemask-based diagnostics derived from pooled samples

The emergence of SARS-CoV-2 and the resulting COVID-19 pandemic has caused a tremendous impact on lives and economies. During the outbreak, clinical testing via reverse-transcription polymerase chain reaction (RT-PCR) was implemented to establish a surveillance system for COVID-19. However, clinical testing reached soon its testing capacity and many people remain undiagnosed due to the relatively long incubation time of 14 days, increasing the risk of spreading the virus. Thus, alternative testing tools need to be developed to enable accessible, inexpensive, and reliable surveillance of virus transmission in communities. In this study, a proof-of-concept for SARS-CoV-2 diagnosis based on pooled wastewater samples from used facemasks was developed as a testing alternative. For the development of this test, a methodology for purification of SARS-CoV-2 synthetic DNA with silica nanoparticles was adapted, and different viral RNA concentrations were successfully evaluated with loop-mediated isothermal amplification (LAMP), nested PCR, and spectrophotometry using Nanodrop. Consistent, positive results were obtained with all the concentrations evaluated, obtaining amplification bands of 200 bp and mean viral loads between 42 - 275 ng/uL. This technology can serve as a solid epidemiological tool to be applied in future epidemiologic health threats to the world population.