Scientists at the Nanyang Technological University (NTU), Singapore, have developed a new diagnostic test that can detect SARS-CoV-2, which causes Covid-19, even when it mutates.
Viruses have the ability to evolve over time and a diagnostic test to detect the virus even after potential mutations will be useful in tracking and fighting the pandemic.
Multiple variants of the virus have already arisen, including some variants that were reportedly spread widely in the UK, South Africa and Brazil.
The new Variant Nucleotide Guard (VaNGuard) test uses a gene-editing tool known as CRISPR, which is widely used in scientific research to alter DNA sequences and modify gene function in human cells under lab conditions.
It provides results within 30 minutes and can be used directly on crude patient samples in a clinical setting without the purification of RNA.
Scientists from the NTU schools of chemical and biomedical engineering, biological sciences, and computer science and engineering; National University Health System; and A*STAR developed the test.
NTU chemical and biomedical engineering school associate professor Tan Meng How said: “Viruses are very smart. They can mutate, edit or shuffle their genetic material, meaning diagnostic tests may fail to catch them.
“Hence, we spent considerable effort developing a robust and sensitive test that can catch the viruses even when they change their genetic sequences.
“In addition, frequent testing is essential for helping to break the transmission of viruses within populations, so we have developed our tests to be rapid and affordable, making them deployable in resource-poor settings.”
The VaNGuard test uses a reaction mix containing enAsCas12a, a variant of the enzyme Cas12a, which acts as a pair of ‘molecular scissors’.
The enzyme targets specific segments of the SARS-CoV-2 genetic material and snips them off from the rest of its viral genome. By successfully snipping off these segments, it identifies the presence of the virus.
The research team has filed a patent for the VaNGuard test and plans to obtain regulatory approval from relevant authorities to commercialise it in partnership with diagnostic companies.