Researchers from the University of California San Diego School of Medicine have created an optical biosensor that can quickly identify monkeypox, the virus that causes mpox, according to a study published in Biosensors and Bioelectronics on November 14th, 2024.
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A new variant of human mpox has claimed the lives of approximately 5 % of those infected in the Democratic Republic of the Congo since 2023, with many of the victims being children. Since its emergence, this variant has spread to several other countries, prompting the World Health Organization to declare the outbreak a Public Health Emergency of International Concern on August 14, 2024. Meanwhile, another mpox variant, though rarely fatal, has been responsible for an outbreak spanning more than 100 countries since 2022.
Addressing the urgent need for faster, more cost-effective diagnostic tools to curb the spread of mpox and prepare for potential future pandemics, researchers from the University of California San Diego School of Medicine, Boston University, and collaborators have developed an innovative optical biosensor.
This device can rapidly detect monkeypox, the virus that causes mpox, enabling point-of-care diagnosis and bypassing the need for laboratory testing. The study, published on November 14, 2024, in Biosensors and Bioelectronics, presents a significant advancement in molecular diagnostics.
Mpox symptoms, including fever, pain, rashes, and lesions, often resemble those of other viral infections, making visual diagnosis unreliable.
So just by looking at the patient, it is not easy for clinicians to distinguish monkeypox from these other diseases.
Partha Ray, Study Co-Principal Investigator an Associate Project Scientist, School of Medicine, University of California San Diego
Currently, polymerase chain reaction (PCR) is the only approved diagnostic method for mpox. However, it is expensive, requires laboratory infrastructure, and may take days or even weeks to yield results.
Ray noted, “A deadly combination when there is a fast-spreading epidemic or pandemic.”
The newly developed biosensor utilizes a digital detection platform called Pixel-Diversity Interferometric Reflectance Imaging Sensor (PD-IRIS). The technology builds on over a decade of research led by Selim Ünlü, a distinguished professor of engineering at Boston University, who has developed optical biosensors for detecting viruses such as Ebola and COVID-19. Collaborating with Ray’s team at UC San Diego, which provided biological expertise and authenticated samples, the researchers applied PD-IRIS to detect monkeypox.
The team collected samples from lesions of a patient with laboratory-confirmed mpox at UC San Diego Health. These samples were incubated briefly with monoclonal antibodies, provided by Ray’s lab, that bind to viral proteins. The virus-antibody complex was then transferred to tiny chambers on silicon chips designed to fix nanoparticles.
When red and blue light were shone on the chips, interference patterns revealed differences caused by the presence of virus-antibody nanoparticles. A color camera detected these signals with high sensitivity, enabling the counting of individual particles.
“You’re not trying to see the scattered light from the virus particle itself, but you’re looking at the interferometric signature of the field of scattered light mixed with the field that is reflected from the surface of the chip,” said Ünlü, likening the process to FM radio, which amplifies weak signals using a more powerful carrier frequency.
The biosensor assay proved capable of distinguishing mpox from other clinically similar viruses, such as herpes simplex and cowpox. “Within two minutes, we can tell whether someone has monkeypox or not,” Ray said. The entire process, from sample collection to results, takes approximately 20 minutes.
This rapid diagnostic capability could allow healthcare providers to identify mpox cases more quickly, especially in regions with limited healthcare resources. Early diagnosis would also facilitate timely treatment and help slow community transmission.
Ray envisions the biosensor being mass-produced as diagnostic kits for use in clinics, further driving down costs. The platform could be adapted for other viruses, such as HIV or syphilis, by simply changing the antibodies used in the test.
“The chip would be the same. The only thing that would be different here is the binding antibody that would be specific for a particular virus,” Ray stated.
Ray and Ünlü are working toward commercializing the biosensor to address the current mpox outbreak and prevent future pandemics. However, they emphasize that government support will be essential to advance these efforts, given the limited market for diagnostics targeting future threats.
Ray concluded, “If we don't take care of this particular epidemic right now, it is not going to be limited within Africa.”
Collaboration and Funding
The study was led by first author Mete Aslan, a Ph.D. student in electrical and electronics engineering at Boston University, and included co-authors from UC San Diego, the Centers for Disease Control and Prevention, and Boston University’s iRiS Kinetics. The work was funded by the National Institute of Allergy and Infectious Diseases at the National Institutes of Health and the National Science Foundation.
This innovative diagnostic tool represents a major step forward in managing mpox outbreaks and highlights the importance of leveraging interdisciplinary collaboration to address global health challenges.
Journal Reference:
Aslan, M. et. al. (2024) A Label-free Optical Biosensor-Based Point-of-Care Test for the Rapid Detection of Monkeypox Virus. Biosensors and Bioelectronics. doi.org/10.1016/j.bios.2024.116932