Universal virus detection platform could replace PCR

The prompt, precise and massive detection of a virus is the key to combat infectious diseases such as COVID-19. A new viral diagnostic strategy using reactive polymer-grafted, double-stranded RNAs, developed by researchers at the Korea Advanced Institute of Science and Technology (KAIST) and described in the journal Biomacromolecules, is thus expected to serve as a pre-screening tester for a wide range of viruses with enhanced sensitivity.

Currently, the most widely using viral detection methodology is polymerase chain reaction (PCR) diagnosis, which amplifies and detects a piece of the viral genome. Prior knowledge of the relevant primer nucleic acids of the virus is quintessential for this test.

By contrast, the detection platform developed by the KAIST researchers identifies viral activities without amplifying specific nucleic acid targets. The research team, co-led by Professors Sheng Li and Yoosik Kim, constructed a universal virus detection platform by utilising the distinct features of the PPFPA-grafted surface and double-stranded RNAs.

The key principle of this platform is utilising the distinct feature of reactive polymer-grafted surfaces, which serve as a versatile platform for the immobilisation of functional molecules. These activated surfaces can be used in a wide range of applications, including separation, delivery and detection. As long double-stranded RNAs are common by-products of viral transcription and replication, these PPFPA-grafted surfaces can detect the presence of different kinds of viruses without prior knowledge of their genomic sequences.

“We employed the PPFPA-grafted silicon surface to develop a universal virus detection platform by immobilising antibodies that recognise double-stranded RNAs,” Prof Kim said. To increase detection sensitivity, the team devised two-step detection process analogues to sandwich enzyme-linked immunosorbent assays, where the bound double-stranded RNAs are visualised using fluorophore-tagged antibodies that also recognise the RNAs’ double-stranded secondary structure.

By utilising the developed platform, long double-stranded RNAs can be detected and visualised from an RNA mixture as well as from total cell lysates, which contain a mixture of various abundant contaminants such as DNAs and proteins. The research team have already successfully detected elevated levels of hepatitis C and A viruses with this tool.

“This new technology allows us to take on virus detection from a new perspective,” Prof Li said. “By targeting a common biomarker — viral double-stranded RNAs — we can develop a pre-screening platform that can quickly differentiate infected populations from non-infected ones.”

“This detection platform provides new perspectives for diagnosing infectious diseases,” Prof Kim added. “This will provide fast and accurate diagnoses for an infected population and prevent the influx of massive outbreaks.”

Image caption: Professor Yoosik Kim, Professor Sheng Li, PhD candidate Sura Kim and PhD candidate Jayoung Ku.

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