The low-cost sensor uses DNA to find diseases like cancer and flu. It works for two months and needs no fridge.
MIT researchers have created a disposable sensor costing just 50 cents that can detect diseases like cancer, HIV, and the flu. Using DNA-coated electrodes and CRISPR enzymes, the sensor changes its electrical signal when it identifies a target gene—making it a promising tool for low-cost diagnostics in clinics and remote areas.
A major challenge with previous versions was the short shelf life, as the DNA coating would degrade quickly. The research team solved this by adding a protective polymer layer made of polyvinyl alcohol (PVA), which helps the sensor last up to two months—even in high temperatures. This coating costs less than a cent per use and protects the DNA from heat and reactive oxygen species, preserving the crucial bond between the DNA and the gold electrode.
The sensor is based on electrochemical detection, similar to glucose meters. It uses a gold leaf electrode laminated onto plastic, with DNA attached via a sulfur-containing thiol molecule. When the CRISPR-associated enzyme Cas12 encounters a target sequence—guided by a specific RNA—it begins cutting surrounding DNA on the electrode. This causes a drop in the electrical signal, which is detected using a potentiostat.
Earlier versions of the sensor had to be freshly prepared before use. With the new PVA coating, the devices are pre-stable and ready-to-use. In lab tests, the coated sensors successfully detected the PCA3 gene, a prostate cancer marker found in urine. They are also compatible with other sample types such as saliva and nasal swabs.
Having already detected genetic material from HIV and HPV in earlier experiments, the researchers are now adapting the sensor for more diseases, including those caused by emerging viruses. Their work has been accepted into MIT’s delta v startup accelerator to move the technology closer to real-world use. The new design’s longer shelf life and resistance to heat make it ideal for areas with limited access to refrigeration or lab infrastructure.
