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| Image created by Dr. Michael J. Miller |
Researchers at Mass General Brigham have developed a diagnostic tool called Luminescence CAscade-based Sensor (LUCAS) that produces highly sensitive, rapid detection of viruses in complex biological samples.
LUCAS generates bioluminescence signals that are 500 times stronger and last eight times longer than those from existing diagnostic methods, addressing key limitations of point-of-care viral diagnostics.
The study was published in Nature Biomedical Engineering.
Improving virus detection with enzyme cascades
Point-of-care diagnostics have become widespread for various applications such as blood sugar monitoring, pregnancy testing and COVID-19 detection, providing quick results without the need for laboratory processing. However, current diagnostics often face challenges including limited sensitivity and false positives. Bioluminescence techniques offer an alternative by producing light signals through enzyme reactions, potentially reducing background noise and phototoxicity.
LUCAS uses a bioluminescence reaction involving the enzyme luciferase, which is naturally found in fireflies, to illuminate viral particles in biological samples. Luciferase acts on a substrate called luciferin, creating a brief light burst that can be difficult to detect due to its low intensity and short duration.
To enhance the signal, the researchers introduced a second enzyme, beta-galactosidase, which continuously releases luciferin by binding to it. This enzyme cascade enables repeated luciferase reactions, generating sustained and amplified bioluminescence. As a result, LUCAS showed 515-fold higher bioluminescent intensity compared to standard methods, with signal strength remaining at 96% after one hour.
Testing LUCAS with multiple viruses
The team tested LUCAS on 177 patient samples and 130 serum samples spiked with viruses including SARS-CoV-2, HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV). Samples were collected via nasopharyngeal swab for SARS-CoV-2 and blood draw for the other viruses. LUCAS delivered diagnostic results within 23 minutes, achieving an average accuracy exceeding 94% across all tested pathogens.
Designed to be portable and user-friendly, LUCAS is suitable for deployment in both high-resource and low-resource point-of-care settings. Future research will explore its performance in detecting multiple pathogens simultaneously and in different biological fluids.
Potential applications and future directions
LUCAS’ ability to enhance bioluminescent signals may also be useful for detecting biomarkers of other diseases, including neurodegenerative disorders such as Alzheimer’s disease. This approach could support early disease detection and monitoring as biomarker identification technologies evolve.
Reference
Kim S, Cho G, Lee J, et al. Ultrasensitive and long-lasting bioluminescence immunoassay for point-of-care viral antigen detection. Nat Biomed Eng. 2025. doi: 10.1038/s41551-025-01405-9
Abstract
Bioluminescence holds notable promise as a modality in diagnostics due to its high signal-to-noise ratio and absence of incident radiation. However, challenges arise from rapid signal decay and reduced enzyme activity when linked to targeting molecules, limiting its reliability in point-of-care diagnostic applications. Here we introduce the luminescence cascade-based sensor (LUCAS) assay, an enzyme cascade system capable of detecting analytes with ultrahigh sensitivity and prolonged bioluminescence. Utilizing a sequential enzymatic reaction, our assay achieves a greater than 500-fold increase in bioluminescence signal and maintains an 8-fold improvement in signal persistence compared to conventional bioluminescence assays. Implemented on a portable, fully automated device designed for point-of-care settings, our system facilitates rapid (<23 min) sample-to-answer analysis of viruses without an external power supply. Its accuracy surpasses 94% in the qualitative classification of 177 viral-infected patient samples and 130 viral-spiked serum samples, various pathogens including the respiratory virus SARS-CoV-2, and blood-borne pathogens such as HIV, HBV and HCV as clinical models. The decentralized, rapid, sensitive, specific and cost-effective nature of LUCAS positions it as a viable diagnostic tool for low-resource environments.