Dr. Benajmin Miller, Proleptic Lectureship in the Department of Medical Physics and Biomedical Engineering
Lateral flow tests, like the ones used for COVID-19, are quick and cheap but they’re not as sensitive as lab-based methods. They typically work by attaching gold nanoparticles (sometimes selenium or latex) to a target, such as a virus protein and when enough particles accumulate, they form a red line. Although widely used, and cost effective, the catch is that if there are only tiny amounts of the target, the line won’t show, and the infection can be missed.
In his research, Ben Miller is replacing gold with nanodiamonds (very very small diamond particles) that contain a tiny defect known as a nitrogen-vacancy (NV) centre. In the diamond’s carbon lattice, if one carbon atom is swapped for nitrogen, with a missing carbon next to it then it radiates fluorescent light: if you shine green light on it, it glows red. Unlike gold, this glow is easy to detect even in small amounts.
Nitrogen-vacancy centres go further in that they exist in different states (spin 0, +1, or –1). These states change how bright the red glow is, and crucially, they can be controlled using microwaves. By switching microwaves on and off, researchers can make the nanodiamond signal flash like a beacon at a known frequency. This makes it possible to detect far smaller amounts of virus, DNA, or proteins by knowing the frequency at which their red emission flashes.
Beyond diagnostics, nitrogen-vacancy centres are also being developed as nanoscale sensors. Researchers around the world are working to measure things like magnetic fields, temperature, or pH inside cells with these nanoscale sensors.
