The thin gold leaf material used to decorate picture frames or lamp bases could also be used to detect viral infections, according to a new study by researchers from Boston University and MIT. They used gold leaf to create a simple device that can be used to detect viral infections without direct access to a medical testing lab. That means it could be used in doctors’ offices or field clinics anywhere in the world, no matter how far they are from a hospital.
Gold leaf is commonly used to apply a gold layer to sculptures, frames, documents or other objects. It’s real gold, but it’s not very expensive. For as little as about $10 you can get a few very thin sheets at an art supply store or on Amazon. That makes it much more affordable than most medical devices, but it does require a bit of crafting to turn it into a virus detector.
To create their virus detector, the researchers cut and shaped the gold leaf into electrodes. By doing this they formed a biosensor which detects a current when a sample is dropped on top. Gold alone is not enough to detect viral infections, so the prototype test also uses a technique called loop-mediated isothermal amplification (LAMP) to create more copies of DNA from the sample (making it easier to detect) and a DNA-recognizing enzyme (Cas12a) to report whether the sample contains genetic material from a specific virus.
All these components are relatively affordable, so with this system the cost per test would be brought down from over $30 to about $2.30. And since the gold leaf device does not require the same access to lab equipment that standard tests need, it can be used in remote locations far from a testing lab.
The research team tested the system by successfully using the gold leaf electrode to detect human papillomavirus (HPV) from cervical swabs but, by adjusting which genetic sequence is recognized by the Cas12a enzyme, it can easily be adapted to pick up other viruses as well, such as HIV or SARS-CoV-2.
Methods to detect viruses are becoming more mobile and accessible as researchers are realising how crucial early and rapid detection can be. Tests based on LAMP and CRISPR have already been used to identify viral infections like Zika or COVID-19 in areas where access to labs is limited. Now this prototype detector adds another possible tool to the virus detection toolkit and all it needs is some gold leaf from the art supply store.