AsianScientist (Nov. 12, 2020) – Researchers from South Korea have developed a one-pot test that can detect the SARS-CoV-2 virus in about 30 minutes. The test, which involves just two chemical reactions, can be easily reconfigured to detect other harmful microorganisms or pathogens, like antibiotic-resistant bacteria and the influenza virus. Their findings were published in Nature Biomedical Engineering.
Currently, the gold standard for COVID-19 diagnosis relies on polymerase chain reaction (PCR). In this technique, the coronavirus’ genetic material is detected and amplified over the course of 90 or so minutes. Despite the test’s high accuracy, it involves a complex preparation process and requires costly equipment as well as skilled technicians. This limits the use of PCR-based tests to centralized laboratories in urban settings.
In light of the urgent need for accessible, yet accurate diagnostics, researchers from the Pohang University of Science & Technology (POSTECH) have developed a test that can easily and quickly diagnose COVID-19 in 30 minutes. Their test, known as SENsitive Splint-based one-pot isothermal RNA detection or SENSR, requires minimal sample processing, making it a convenient alternative to PCR-based tests.
SENSR consists of two simple chemical reactions that occur sequentially at 37°C: First, two DNA probes are chemically joined together or ligated to target RNA in the sample. Next, the ligation product is transcribed into a short RNA strand that binds to fluorescent dyes. This means that fluorescent signals are only given off when pathogenic RNA is present. Otherwise, the unbound dyes release their energy in the form of heat and molecular vibrations.
To validate their method, the researchers first applied SENSR to detect the RNA of methicillin-resistant Staphylococcus aureus, one of the leading causes of hospital-acquired infections. In just 30 minutes, they were able to detect as little as six molecules of the target RNA in every 100 microliters of the reaction. By redesigning the DNA probes using available genetic sequences, the team discovered that they could easily customize SENSR to detect a wide variety of pathogens—including SARS-CoV-2 in actual patient samples.
As SARS-CoV-2 is highly similar to other coronaviruses, the researchers decided to further refine SENSR to detect multiple target RNAs. They achieved this by simply including additional DNA probes into the reaction, finding that these probes could accurately detect other sites on SARS-CoV-2’s RNA. With its fast turnaround time, high sensitivity and easy customizability, SENSR shows promise for rapid infectious disease screening.
Further research efforts will focus on automating the design of the DNA probes. In doing so, the researchers hope to accelerate the development of SENSR tests for newly-emerging pathogens like SARS-CoV-2.
“This method is a fast and simple diagnostic technology which can accurately analyze the RNA without having to treat a patient’s sample,” commented Professor Lee Jeong Wook, who co-led the study. “We can better prepare for future epidemics as we can design and produce a diagnostic kit for new infectious diseases within a week.”
Source: Pohang University of Science & Technology; Photo: Shutterstock.
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