NYU-Poly Researchers Detect Smallest Virus, Opening Possibilities for Early Disease Detection

Professor Steve Arnold’s research team at NYU-Poly has created an ultra-sensitive biosensor capable of identifying the smallest single virus particle one at a time in solution, an advance that may revolutionize early disease detection and shrink test result wait times from weeks to minutes.

Arnold, university professor of applied physics and member of the Othmer-Jacobs Department of Chemical and Biomolecular Engineering, and researchers of NYU-Poly's MicroParticle PhotoPhysics Laboratory for BioPhotonics (MP3L) reported their findings in Applied Physics Letters. The research was originally supported by provost seed funds from the NYU School of Arts and Sciences.

They have created a biosensor sensitive enough to detect and measure a single virus particle in a doctor’s office or field clinic, without the need for special assay preparations or conditions. Normally, this would require the virus to be measured in the vacuum environment of an electron microscope, which adds time, complexity and considerable cost.

Instead, the researchers were able to detect the smallest RNA virus particle, MS2 with a mass of only 6 attograms. Within the Whispering Gallery-Mode Biosensor, light from a tunable laser is guided down a fiber optic cable, where its intensity is measured by a detector on the far end. A small glass sphere is brought into contact with the fiber, diverting the light's path and causing it to orbit within the sphere. This change is recorded as a resonant dip in the transmission through the fiber. When a viral particle makes contact with the sphere, it changes the sphere’s properties, resulting in a detectable shift in resonance frequency.

The smaller the particle, the harder it is to record these changes. Viruses such as influenza are fairly large and have been successfully detected with similar sensors in the past. But many viruses such as Polio are far smaller.

Arnold and his co-researchers achieved the required sensitivity by attaching gold nano-receptors to the resonant microsphere that have been treated with specific molecules that attract and bind proteins and viruses. These receptors are plasmonic, and thus enhance the electric field nearby, making even small disturbances easier to detect.

The researchers are setting their sights on detecting single proteins like antibodies, a major step toward early disease detection. “If we can identify and detect these single proteins,” Arnold said, “we can diagnose the presence of a virus far earlier, speeding treatment.” He continued, “This also opens up a new realm of possibilities in proteomics. All cancers generate markers, and if we have a test that can detect a single marker at the protein level, it doesn’t get more sensitive than that.”