UConn researcher’s COVID-19 home test comparable to PCR accuracy and selectivity

As demand skyrockets for tests that can quickly detect COVID-19, with pharmacies and grocery stores nationwide selling tests as quickly as they can be stocked, UConn researcher aims to bring home testing better and more reliable.

Changchun Liu, an associate professor in the Department of Biomedical Engineering who developed a paper-based laboratory diagnostic platform and a pH paper-based visual extraction and detection device (called pH-EVD) for SARS-CoV- 2, the virus that causes COVID-19, is working to make its rapid tests available for home use.

The lab-on-paper platform detects two SARS-CoV-2 genes that are highly conserved across all variants. So even if the virus mutates, Liu’s test will still be able to detect it. The pH-EVD test provides a simple binary response to patients: positive or not for the SARS-CoV-2 virus.

Liu’s tests work much like a PCR test, which is the gold standard for detecting SARS-CoV-2 and required in many situations, such as before international travel, certain surgeries and, more recently, before d to access certain sporting events.

PCR tests are more reliable than rapid home tests because PCR tests look for the presence of SARS-CoV-2 genetic material, allowing them to detect active viral molecules – much like Liu’s test.

Currently available rapid tests check for the presence of antigens against SARS-CoV-2. If an infected person has not generated enough antigens when they take the test, they could get a false negative result. This is a potentially significant issue, as someone could unknowingly spread the virus for days before a rapid test picks up the infection. These tests can also give false positive results if they detect antigens after the infection or an old infection has passed.

While Liu’s devices and PCR tests are designed to detect SARS-CoV-2 genetic material, Liu’s devices are more like a rapid test, as they are inexpensive, easy to use, and much faster than the PCR tests.

After taking a sample from a nasal swab, it is added to Liu’s specially formulated paper and placed in the smart cup. Results are indicated by distinctive staining – yellow for positive and green for negative. (Changchun Liu)

Liu’s pH-EVD device has 100% specificity, meaning it only detects SARS-CoV-2. This is comparable to PCR testing. It also has an 89% accuracy when it comes to detecting the presence or absence of the virus. Liu published these findings in Advanced NanoBIOMED Research.

“In our lab, we validated the performance of our technology using COVID-19 clinical samples,” Liu says. “It’s comparable to PCR technology.”

It’s hard to compare this to currently available rapid tests, as there are so many on the market. But one study suggests that the BinaxNOW test has a sensitivity of 87% in symptomatic individuals and 71% in asymptomatic individuals.

Liu’s pH-EVD device incorporates a cellulose-based pH paper membrane, like many rapid tests currently available. It carries the liquid that contains the sample, obtained from a nasal swab. The pH paper produces color signals to indicate a positive or negative result in 40 minutes, compared to days for PCR results.

Patients would receive lab test results without having to visit a lab or clinic.

The pH-EVD device requires no electricity to operate, making it much more affordable than PCR testing. Instead, it uses heat automatically generated from chemical reactions to power the process. This allows nucleic acids to amplify at a constant temperature. This amplification is what allows the technology to pick up viral genes.

This platform can also be applied to diagnose other viruses such as HIV, influenza viruses or high-risk HPV by modifying the genes it selects.

The paper-based laboratory diagnostic platform uses CRISPR technology to detect SARS-CoV-2 genes. As a diagnostic tool, CRISPR locates genes of interest and cuts them. This clip produces an observable signal, which on Liu’s platform appears as fluorescence filling into the paper to indicate a positive result. The device also tests for a “housekeeping” gene. This gene will mark the paper to indicate that the test was performed correctly with a high quality sample.

“I think in the near future, ideally, the diagnosis of infectious diseases will be done at home and in small clinics,” Liu said. “This technology can adapt to home COVID-19 diagnosis or diagnosis of other diseases. If commercialized successfully, I think there is a very large market.

Liu has filed a strong portfolio of diagnostic-related technology patent applications with UConn Technology Commercialization Services. One of its technologies was successfully granted an exclusive license in February 2021. UConn is actively seeking a company capable of commercializing the technology and all interested parties are welcome to contact: [email protected]

“UConn’s Technology Commercialization Services works with innovators, entrepreneurs, investors and industry partners to turn UConn’s discoveries into products, businesses and jobs that benefit society and fuel development. economic. Through a coordinated approach between technology transfer, licensing, and start-up teams, TCS delivers services that enable success for colleges, businesses, Connecticut, and beyond.

The Department of Biomedical Engineering is a shared department with the UConn School of Dentistry, School of Medicine, and School of Engineering.

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