Researchers at Mass General Brigham have developed a new diagnostic method that significantly enhances virus detection by harnessing bioluminescence. The tool, called the Luminescence CAscade-based Sensor (LUCAS), was designed to be portable, fast, and highly sensitive and is capable of diagnosing SARS-CoV-2, HIV, hepatitis B (HBV), and hepatitis C (HCV) with over 94% accuracy in less than 23 minutes. Details of the new point-of-care diagnostic tool are published 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,” said senior author Hadi Shafiee, PhD, an associate professor of Medicine at Brigham and Women’s Hospital. “Finding an HIV particle in a human blood sample is like finding an ice cube in a jelly-filled Olympic swimming pool while blindfolded.”
Point-of-care diagnostics frequently suffer from limitations like poor sensitivity, background signal interference, and short-lived readouts. Bioluminescence has been explored to address some of these issues. Traditional methods rely on the enzyme luciferase to emit light when reacting with its substrate, luciferin, but these reactions tend to produce weak, rapidly fading light, limiting their diagnostic utility.
Shafiee’s team engineered a novel bioluminescence system that largely eliminates these shortcomings. By introducing an enzymatic cascade that incorporates beta-galactosidase into the process, they created a system where luciferin is gradually released instead of being consumed all at once. This results in a prolonged and intensified luminescent reaction.
“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,” the researchers noted.
The LUCAS diagnostic performance was evaluated by the Mass General team using 177 viral-spiked patient samples and viral-spiked 130 serum samples. Viruses used in these tests included nasopharyngeal swabs for SARS-CoV-2 and blood samples for HIV, HBV, and HCV. The portable system demonstrated rapid and accurate results across all virus types and sample types without requiring an external power source.
Bioluminescence has been employed previously in diagnostic applications due to its high signal-to-noise ratio and lack of background interference from incident light. However, as the researchers noted, “challenges arise from rapid signal decay and reduced enzyme activity when linked to targeting molecules, limiting its reliability in point-of-care diagnostic applications.” LUCAS was developed specifically to address these shortcomings.
The assay was implemented on a fully automated portable platform, making it viable for use in both high- and low-resource environments. The researchers designed the system for potential deployment in decentralized healthcare settings, including remote clinics or for use as an in-field diagnostic.
The researchers reported that the strengths of LUCAS include its signal strength, rapid result time, portability, and lack of need for complex laboratory infrastructure. Limitations of the current researcher include its validation in a limited set of sample types and pathogens, as well as the need for further testing to confirm robustness in real-world conditions.
An advantage of the LUCAS system, the researchers noted, is its adaptability. Shafiee said its design could be modified to test for different diseases as new biomarkers are discovered and future development of the system will examine the diagnostic’s ability to function in other biological fluids and assess its capacity for detecting multiple pathogens simultaneously.
“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 author Sungwan Kim, PhD, a postdoc in the Shafiee lab. “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.”
