Medical diagnosis could become more democratic than ever before. A DNA sensor created by researchers at MIT can detect cancer and HIV with the same precision as the most advanced laboratories, but at a fraction of the cost. How does it work? A gold strip covered in DNA reacts to the presence of diseases by changing its electrical properties. All in five minutes, without the need for a refrigerator or specialized personnel. If today we have to wait days for test results, this DNA sensor gives us back control over our health in real time, wherever we are. It can really change our future.
A DNA sensor that costs less than a coffee
The new electrochemical device developed by the team of Ariel Furst at MIT is a breakthrough in point-of-care diagnostics. With a production cost of only 50 cents, This DNA sensor uses a gold leaf electrode laminated onto plastic, with the DNA anchored via a sulfur-based molecule called thiol. The technology is based on a very effective principle: when the Cas12 enzyme of the CRISPR family encounters the specific target, it is activated and begins to “chop up” the surrounding DNA on the electrode. As Professor Furst explains in the article published in the magazine ACS Sensors: “If Cas12 is active, it’s like a lawnmower cutting off all the DNA on your electrode, turning off the signal.” This change in electrical signal is read by a portable device called a potentiostat, confirming the presence of the target gene.
The real innovation lies in the way the DNA sensor “thinks” at the molecular level. The system uses a programmable guide RNA linked to the Cas12 enzyme, which can be designed to bind to almost any DNA or RNA sequence. When the target is present, it binds to the guide RNA and activates Cas12, which then nonspecifically “cuts” the DNA attached to the electrode. In previous versions, the DNA had to be applied to the electrode shortly before use, because it was not stable for long. But the researchers solved this crucial problem by coating the DNA in polyvinyl alcohol (PVA), a polymer that costs less than a cent per coating and acts like a protective sheet.
Stability that changes everything for the DNA sensor
The most important discovery concerns the durability of the device. The polymer coating keeps DNA stable for at least two months, resisting temperatures up to 65°C. After storage, the film is rinsed and the DNA sensor can still successfully detect PCA3, a prostate cancer gene present in urine.
“Once dry, it appears to form a very strong barrier against the main substances that can damage DNA,” Furst points out. This stability eliminates the need for refrigeration and allows the sensors to be shipped anywhere in the world, paving the way for diagnostic testing in harsh or non-ideal environments.
Practical applications
The test works with several types of samples, including saliva and nasal swabs, and can be adapted for low-cost detection of infectious diseases such as HPV and HIV. In 2021, Furst's lab had already demonstrated the effectiveness of these sensors in detecting genetic material from HIV and human papillomavirus..
The platform is flexible enough to be adapted for emerging pathogens, which is critical in an era of rapidly evolving health threats. Some members of Furst's lab have joined the startup accelerator program delta v at MIT, with the goal of bringing this technology from the lab to the market.
Towards a world without diagnostic barriers
The team's stated goal is clear:
“Our focus is on diagnostics that a lot of people have limited access to, and our goal is to create a point-of-use sensor. People don’t even have to be in a clinic to use it. You could do it at home,” Furst says.
This innovation is part of a broader panorama of developments in molecular diagnostics, where miniaturization and democratization of diagnostic tools are redefining access to medical care. “Our limitation before was that we had to produce the sensors on site, but now that we can protect them, we can ship them. We don’t have to use refrigeration. This gives us access to a lot more challenging or non-ideal environments for testing,” Furst concludes.
A 50-cent DNA sensor that promises to bring the diagnostic precision of the most advanced laboratories directly into our homes: the present knocks on the door of the future.
