A scalable aptamer-based electrochemical biosensor for rapid detection of SARS-CoV-2 from saliva - Abstract
The COVID-19 pandemic is a critical global public health emergency and many countries are failing to contain
the virus's spread due to slow and insufficient testing. While several diagnostic methods are now available, most
tests are either reagent-intensive and must be done in CLIA-approved labs, making them expensive and slow to
report 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 of
which are the most effective spreaders of the virus. However, expanding testing has been a challenge due to
shortages of sampling swabs and key reagents for nucleic acid amplification-based tests, which are the most
popular option. Testing capabilities must be expanded exponentially to enable mass population-level testing of
all patients, healthcare workers and their families, other critical key workers, and the wider community in order
to bring the pandemic under control. mPOD proposes to expand testing capabilities through a novel biosensor
that 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, making
them particularly suited for high-specificity binding. To complete the test, a saliva sample will be loaded onto a
test strip containing aptamers immobilized onto gold electrodes. The gold-electrode test strip will be inserted into
the mPOD DTCT, a proprietary electrochemical test platform where virus-bound aptamers will be detected via
cyclic voltammetry, triggering a positive result. The result is sent wirelessly via a mobile app, which sends
encrypted 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 order
to further develop this technology and enable rapid deployment for timely COVID-19 intervention, mPOD plans
to 1) Select SARS-CoV-2-specific aptamers for use in electrode test strips with an optimized signal-to-noise ratio
performance, 2) Demonstrate sensitivity and specificity of a low-cost, miniaturized potentiostat test strip for use
as a COVID-19 POC or OTC diagnostic, 3) Complete and test a fully-fledged digital infrastructure for data
collection, tracking, and tracing of COVID-19 test results via the mPOD mobile app. This non-traditional approach
will provide new testing capabilities with the potential to report results faster than standard RT-PCR tests and
with greater accuracy and sensitivity compared to existing antigen-based diagnostics. Furthermore, once the
system is developed, test strips with customized aptamers can be developed for rapid diagnosis of other
pathogens, including future emerging pandemics, via routine POC and OTC testing.
