Nature sub-journal: New portable diagnostic device detects SARS-CoV-2 RNA and antibodies simultaneously

As the COVID-19 pandemic has developed, the questions we've been asking ourselves have gone from "How do I know if I'm infected?" to "How strong is my immunity?" to "Which virus am I?" "And, as new variants keep popping up, we're likely to be asking ourselves these questions all the time, often at the same ti.

Now, there's a way to get all your questions answered in a matter of hours without sending samples to a l.

Devora Najjar, a graduate student at the MIT Media Lab and the Wyss Institute and one of the first authors, said: "This diagnostic approach allows for cheaper, multiplexed monitoring of infection and immunity in a population over time, Its accuracy is comparable to expensive laboratory tes.

New chemical composition of new virus

The diagnosis resulted from a collaboration between the labs of Wyss College core faculty member Jim Collins , .

“In the early days, everyone was working on developing diagnostics that could detect either the SARS-CoV-2 virus or antibodies, but not bo.

But creating a platform that can integrate viral RNA and human protein detection has been a challen.

They chose saliva as the sample material because both virus particles and antibodies can be found the.

The team designed a microfluidic system consisting of multiple reservoirs, channels and heating elements that can automatically mix and transport substances within the prototype device without requiring user inp.

In the absence of SARS-CoV-2 genetic material in the mixture, single-stranded (ssDNA) molecules with biotin bind to peptide nucleic acid (PNA) molecules on the electrode surfa.

However, if any SARS-CoV-2 genetic material was present in the saliva sample, the CRISPR enzyme in the SHERLOCK mix would cut it and the ssD.

"The PNA-based assay combined with the multi-enzyme-labeled streptavidin/TMB reaction chemistry we created for this device allowed us to detect the presence of SARS-CoV-2 with greater sensitivity than our original fluorescence-based SHERLOCK technology 4 times and produce results in about the same time," said co-first author Dr Joshua Rainbow, a former visiting postgraduate student at the Wyss Institute and now a PhD student at the University of Ba.

greater than the sum of the parts

At the same time, the team customized the remaining 3 eRapid electrodes, embedding different COVID-related antigens to which patients can produce antibodies: the S1 subunit of the spike protein (S1), the ribosome binding domain within this subunit ( S1-RBD) and the N protein, which is present in most coronaviruses (.

The researchers tested these antibody-specific sensors using human plasma samples from patients who had previously tested positive for SARS-CoV- The system was able to distinguish antibodies against S1, S1-RBD and N proteins with over 95% accura.

"Being able to easily distinguish between different types of antibodies is very beneficial for determining whether a patient's immunity is due to a vaccine or an infection, and to track the strength of these different levels of immunity over time," said .

Finally, the team tested the bound viral RNA and antibody electrodes using saliva from SARS-CoV-2 patien.

"Currently, there is a lack of low-cost diagnostic platforms that can accurately detect a wide range of molecules without the need for a trip to the l.

The low-cost and compact design of this prototype device is user-friendly, minimizing the number of steps the patient needs to perform, reducing the possibility of manipulation erro.

Custom-made cartridges can be easily fabricated to detect antigens and antibodies for different diseases, regardless of usage scenari.

Lab-on-a-chip multiplexed electrochemical sensor enables simultaneous detection of SARS-CoV-2 RNA and host antibodies