A scalable aptamer-based electrochemical biosensor for rapid detection of SARS-CoV-2 from saliva

AbstractThe COVID-19 pandemic is a critical global public health emergency and many countries are failing to containthe virus's spread due to slow and insufficient testing. While several diagnostic methods are now available, mosttests are either reagent-intensive and must be done in CLIA-approved labs, making them expensive and slow toreport results, or rapid and inexpensive, but potentially lacking in sensitivity. In the U.S., seriously ill and high-risk patients have been prioritized for testing, causing states to miss mild and asymptomatic cases, some ofwhich are the most effective spreaders of the virus. However, expanding testing has been a challenge due toshortages of sampling swabs and key reagents for nucleic acid amplification-based tests, which are the mostpopular option. Testing capabilities must be expanded exponentially to enable mass population-level testing ofall patients, healthcare workers and their families, other critical key workers, and the wider community in orderto bring the pandemic under control. mPOD proposes to expand testing capabilities through a novel biosensorthat will use oligonucleotide molecules called aptamers to bind to unique sites on the SARS-CoV-2 virus.Aptamers have similar binding affinities to antibodies, but due to their smaller size, they are more agile, makingthem particularly suited for high-specificity binding. To complete the test, a saliva sample will be loaded onto atest strip containing aptamers immobilized onto gold electrodes. The gold-electrode test strip will be inserted intothe mPOD DTCT, a proprietary electrochemical test platform where virus-bound aptamers will be detected viacyclic voltammetry, triggering a positive result. The result is sent wirelessly via a mobile app, which sendsencrypted data on to the cloud for storage and to public health agencies for enhanced data collection, tracking,and tracing of COVID-19. The app will also include a backend database to help businesses, manufacturers,schools, and large institutions track tested individuals' results and tailor specific public health responses. In orderto further develop this technology and enable rapid deployment for timely COVID-19 intervention, mPOD plansto 1) Select SARS-CoV-2-specific aptamers for use in electrode test strips with an optimized signal-to-noise ratioperformance, 2) Demonstrate sensitivity and specificity of a low-cost, miniaturized potentiostat test strip for useas a COVID-19 POC or OTC diagnostic, 3) Complete and test a fully-fledged digital infrastructure for datacollection, tracking, and tracing of COVID-19 test results via the mPOD mobile app. This non-traditional approachwill provide new testing capabilities with the potential to report results faster than standard RT-PCR tests andwith greater accuracy and sensitivity compared to existing antigen-based diagnostics. Furthermore, once thesystem is developed, test strips with customized aptamers can be developed for rapid diagnosis of otherpathogens, including future emerging pandemics, via routine POC and OTC testing.