Loop-mediated isothermal amplification (LAMP) is a technique that allows for nucleic acid amplification without the need for a thermocycler. This technology enables testing for infections practically anywhere. Testing shortages have exacerbated the COVID-19 pandemic, and there is a high demand for tests that can provide rapid results outside of a hospital or clinical laboratory setting. Despite the advantages, isothermal amplification techniques have not been used in a diagnostic setting because of the low limit-of-detection (false negatives), errant amplification (false positives), and long assay times.
The Ellington Lab at The University of Texas at Austin has designed a new amplification enzyme that overcomes previous performance barriers of LAMP assays. The evolved DNA polymerase, Br512, works with strand displacing probes that can effectively eliminate false positives. Br512 has a significantly better limit-of-detection than the gold-standard Bst2.0 enzyme. This new enzyme is robust and sensitive; it can detect as few as 5,000 COVID-19 virions in crude saliva samples. Br512 can improve LAMP assays to enable accurate, low-cost, and rapid point-of-need detection of infectious agents like COVID-19.