Liquid Crystals to Power More Efficient COVID-19 Tests
Liquid crystals (LCs), the technology behind television screens, thermometers and even mood rings, may soon transform rapid coronavirus (COVID-19) testing.
Researchers at the University of Arkansas (UArk) and the University of Alabama (UA) in North America have developed a prototype that delivers accurate results in under two minutes, even at very low viral levels.
The substance has rod-shaped molecules that typically align in neat rows. In LCD screens, an electric charge shifts their orientation to control light.
In this new test, the crystals re-orient when the COVID-19 spike protein binds to a metallic surface. As LCs “follow the herd”, meaning several molecules trigger a visible chain reaction, making results detectable to the naked eye.
In trials, the sensor detected just 2 000 spike proteins per millilitre, far below the tens of thousands typically present in an infected saliva sample.
Unlike standard lateral flow tests, it also showed reversibility: after introducing antibodies, the crystals returned to their original state. The sensor proved specific to SARS-CoV-2, avoiding false positives from unrelated molecules.
“That’s the beauty of liquid crystals. You can capture these events on the surface and transmit them over much larger length-scales,” said Karthik Nayani, test co-author and UArk assistant professor of chemical engineering.
Beyond COVID-19, the UArk/UA research team believes the approach could detect future, unknown pathogens, offering a rapid response to emerging pandemics.
The same principles could also be adapted for airborne detection of chemical weapons, pesticides or harmful gases like formaldehyde, extending the technology’s potential far beyond medicine.
