Researchers have created an optical biosensor capable of detecting the mpox virus. This innovative technology has the potential to expedite and lower the costs of diagnosing the disease amid its ongoing global spread.
Since 2023, a new strain of human mpox has caused approximately 5% of reported infections in the Democratic Republic of the Congo to result in death, primarily among children. This strain has since extended its reach to several other nations. On August 14, the World Health Organization labeled the outbreak a Public Health Emergency of International Concern. Additionally, a different yet less deadly variant of mpox has contributed to an outbreak affecting over 100 countries since 2022.
There is an immediate need for improved diagnostic tools to help control the spread of mpox and to prepare for any potential future pandemics. A team of researchers from the University of California School of Medicine, Boston University, and their partners have invented an optical biosensor that can quickly identify monkeypox, the virus behind mpox. This advancement could enable healthcare professionals to diagnose the illness directly at the point of care instead of waiting days for lab results. This study was published on November 14, 2024, in Biosensors and Bioelectronics.
According to Partha Ray, an associate project scientist at UC San Diego School of Medicine and co-leader of the study, mpox symptoms such as fever, pain, rashes, and lesions are similar to those of various other viral infections. “Therefore, it’s not easy for healthcare providers to differentiate monkeypox from other diseases just by examining the patient,” he explains.
Currently, polymerase chain reaction (PCR) is the only approved diagnostic method for mpox. It’s costly, requires laboratory facilities, and results can take days or even weeks. Ray describes this as a “deadly combination during a rapidly spreading epidemic or pandemic.”
The quest for superior mpox diagnostics builds on over a decade of research in the lab of Selim Ãœnlü, a noted engineering professor at Boston University and co-leader of the study. His lab has previously developed optical biosensors that identify viruses responsible for Ebola and COVID-19, among others. Ray’s team at UC San Diego contributed biological knowledge and validated samples to Ãœnlü’s engineering group.
This study, led by Mete Aslan, a Ph.D. student in electrical and electronics engineering at BU, employed a digital detection platform known as Pixel-Diversity Interferometric Reflectance Imaging Sensor (PD-IRIS) to identify the virus.
The team analyzed samples taken from the lesions of a patient at UC San Diego Health whose mpox diagnosis had been confirmed in the lab. They first incubated these samples with monoclonal antibodies for monkeypox, which bind to proteins on the virus’s surface. This virus-antibody complex was then placed into tiny chambers on silicon chips in the sensor designed to capture these nanoparticles.
By directing specific wavelengths of red and blue light on the chips, interference occurred, leading to slightly different reactions when nanoparticles of the virus-antibody complex were present. A color camera recorded this minute signal and counted individual particles with exceptional sensitivity.
Ãœnlü explains the process, stating, “Rather than observing the light scattered from the virus particle itself, we focus on the interferometric signature created by the scattered light mixed with light reflected from the chip’s surface.” He compares it to FM radio, where a weak signal containing information gets combined with a stronger carrier signal at the same frequency, enhancing the weaker signal.
The team also tested samples of herpes simplex virus and cowpox virus, which present similarly to mpox. Their biosensor successfully differentiated mpox samples from these viruses, confirming the assay’s ability to distinguish mpox from other common viral diseases.
“In just two minutes, we can determine whether someone has monkeypox,” Ray stated. “From the moment we collect the virus samples to receiving real-time data takes approximately 20 minutes.”
This rapid testing capability means that healthcare providers can diagnose mpox much faster than waiting for lab results. This is particularly crucial for mitigating community spread in nations with limited healthcare resources. It also allows for quicker initiation of treatment if it’s available.
Ray envisions mass production of these tests as kits, which would significantly lower costs. A single kit could be used to test for multiple viruses, including syphilis or HIV.
“The chip will remain unchanged,” Ray explained. “The only variation would be the binding antibody tailored for a specific virus.”
Ray and Ünlü are collaborating towards commercializing this technology—not only to tackle the pressing need for rapid mpox testing in the Democratic Republic of the Congo but also to prevent outbreaks from escalating into pandemics. However, they emphasize that this initiative necessitates government backing since there is minimal market incentive for diagnostics targeting future threats.
“If we don’t effectively address this particular epidemic now, it won’t stay confined to Africa,” Ray warned.
Additional co-authors of the study include: Howard Brickner, Alex E. Clark, Aaron F. Carlin from UC San Diego; Elif Seymour from iRiS Kinetics, Boston University Business Incubation Center; Michael B. Townsend and Panayampalli S. Satheshkumar from the Centers for Disease Control and Prevention; Iris Celebi from Boston University; and Megan Riley from axiVEND.
The research received partial funding from the National Institute of Allergy and Infectious Diseases at the National Institutes of Health (P30 AI036214), as well as from the National Science Foundation (NSF-TT PFI 2329817).
