Bioluminescent reactions, where light is emitted from a living being, have a lot of potential applications in biomedical research and diagnostics. Many assays already exist that depend on luciferase, the natural enzyme responsible for many bioluminescent reactions. Scientists have now created a rapid diagnostic tool that can assess biological samples to identify virus particles, using bioluminescence
This new assay is called Luminescence CAscade-based Sensor (LUCAS), and this highly sensitive tool is over 500 times stronger and lasts eight times longer than the signals in other bioluminescent assays. This method aims to overcome many limitations in current diagnostic tools, and it has been reported in Nature Biomedical Engineering.
“Developing effective diagnostics is incredibly challenging, especially when you think about the size of infectious disease particles and the complicated biological fluids we’re attempting to identify them in. Finding an HIV particle in a human blood sample is like finding an ice cube in a jelly-filled Olympic swimming pool while blindfolded,” explained senior study author Hadi Shafiee, Ph.D., a faculty member at Brigham and Women’s Hospital, among other appointments. “With its novel enzyme cascade approach, LUCAS marks a substantial leap forward for sensing viruses in these complex biological samples.”
Point-of-care diagnostics assays like pregnancy tests, blood sugar measurements, and COVID-19 tests are commonly found in households now. But they are not perfect, and some have accuracy and sensitivity problems, meaning they can fail to properly diagnose a condition, or may deliver a false positive.
Bioluminescence could overcome some of these problems, such as photobleaching, phototoxicity, false positives, or background noise that makes tests hard to interpret or delivers unreliable results.
In luciferase assays, the luciferin is modified so that when it is added to a sample, it will emit light when it interacts with target particles in that sample. Usually, that light is only emitted for a short time. But in this work, the researchers added another enzyme to the reaction known as beta-galactosidase. It causes the continuous release of luciferin, so that the bioluminescence persists.
The new method, known as LUCAS, was found to be 515 times more bioluminescent than other systems, and the strength of the signal was maintained at 96% for an hour.
LUCAS was able to accurately diagnose, HIV, HBV, or HCV in blood samples and SARS-CoV-2 in nasopharyngeal swab samples within 23 minutes, 94% of the time. The test is designed to be portable and used with minimal resources.
“We always want to detect infection and disease as early as possible, as that can make all the difference when it comes to care and long-term outcomes,” said first study author Sungwan Kim, Ph.D., a postdoctoral researcher in Shafiee’s lab at the Brigham. “With our focus on developing diagnostic tools that are sensitive, accurate, and accessible, we want to make early detection easier than it has ever been and push personalized care into a new era.”
Sources: Mass General Brigham, Nature Biomedical Engineering