Optical biosensor rapidly detects monkeypox virus

An undated colorized transmission electron micrograph of mpox virus particles (pink) found within an infected cell (yellow), cultured in the laboratory, captured at the National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility (IRF) in Fort Detrick, Maryland.
| Photo Credit: Reuters

A new variant of human mpox has claimed the lives of approximately 5% of people with reported infections in the Democratic Republic of the Congo since 2023, many of them children. Since then, it has spread to several other countries. In addition, a different but rarely fatal mpox variant was responsible for an outbreak that has spread to more than 100 countries since 2022. There is an urgent need for faster and more cost-effective diagnostic tools to curb the spread of mpox and to prepare for the possibility of a future global pandemic.

Researchers from University of California San Diego School of Medicine, and Boston University have now developed an optical biosensor that can rapidly detect monkeypox, the virus that causes mpox. The technology could allow clinicians to diagnose the disease at the point of care rather than wait for lab results. The study was published on November 14, 2024 in Biosensors and Bioelectronics.

In the clinic, mpox symptoms such as fever, pain, rashes and lesions resemble those of many other viral infections. So it is not easy for clinicians to distinguish monkeypox from these other diseases by just looking at the patient.

A PCR test is expensive, requires a laboratory, and can take days or weeks to get results. The Boston University lab has developed optical biosensors for detecting the viruses that cause Ebola hemorrhagic fever and COVID-19, among others.

The researchers used samples collected from the lesions of a patient with laboratory-confirmed mpox. They briefly incubated the samples with monoclonal monkeypox antibodies that bind to proteins on the surface of the virus. The virus-antibody complex was then transferred into tiny chambers on the surface of silicon chips on the sensor that were treated to fix these nanoparticles. 

Shining precise wavelengths of red and blue light simultaneously on the chips caused interference, which resulted in slightly different responses when the virus-antibody nanoparticles were present. A colour camera was used to detect this small signal and count individual particles with high sensitivity. The biosensor assay easily discriminated mpox samples from these other viruses within two minutes.