Home Diagnostics For Pennies: Revolutionary Sensor Detects Cancer And HIV

Scientists at MIT have created a cheap, disposable sensor that uses DNA and CRISPR technology to detect diseases such as HIV and cancer. The sensor works without the need for refrigeration and can be stored for up to two months, even at high temperatures. It identifies signs of disease in samples such as saliva or urine and costs less than 50 cents, making it possible to diagnose diseases quickly and easily, even at home.

In the near future, it may be possible to diagnose serious diseases such as HIV, HPV, or even cancer using a simple, inexpensive, home-based test, all thanks to innovative sensors developed by MIT researchers.

At the heart of this technology is a tiny electrode, a key component of the sensor, made of a metal strip (usually gold) coated with DNA molecules. This electrode is capable of identifying very specific signs of disease, working in a similar way to glucose tests that measure blood sugar.

These sensors are part of a category called electrochemical biosensors, which detect diseases by recording changes in electrical current caused by interactions with molecules in the human body, such as genes or proteins. The great advantage of this type of sensor is that it is fast, sensitive (capable of identifying even small amounts of genetic material) and can be adapted to various diseases.

A key innovation in this new MIT sensor is the use of CRISPR technology, a genetic system that cuts DNA, to activate the sensor in an extremely specific way.

Here’s how it works: DNA attached to the electrode is programmed to recognize a specific gene linked to a disease. When the sensor is exposed to a sample (such as urine, saliva or a nasal swab), and if that gene is present, the CRISPR enzyme (called Cas12) is activated. It acts like a lawnmower, “chopping up” all the DNA around it.

This changes the electrode’s electrical signal, allowing the sensor to “sense” that something is wrong, and all of this can be read by a small, portable device.

Despite their enormous potential, sensors like these had one problem: the DNA coating the electrode was fragile. It could degrade over time, especially at high temperatures or outside of the refrigerator, which required the sensors to be used soon after manufacture. This severely limited their use in places without medical infrastructure, such as remote communities or developing countries.

To solve this challenge, the scientists used a simple protective coating made from a material called PVA (polyvinyl alcohol), the same material used in glues and plastic films. This material forms a thin layer over the electrode, protecting the DNA from heat, oxygen and other conditions that would normally destroy it.

With this coating, the sensor can be stored for at least two months, even at temperatures as high as 65°C, without losing its ability to accurately detect diseases.

One demonstration test used the sensor to identify a gene linked to prostate cancer (PCA3) in urine, successfully detecting it even after weeks of storage. The sensor also worked with saliva and nasal swabs, and could easily be adapted to detect other infectious diseases, such as HIV and HPV. Best of all, each sensor costs less than 50 cents to produce.

Test that used square wave voltammetry (SWV), an electrochemical technique, to verify whether the DNA present in functional electrodes was still intact after 14 days of storage protected by a layer of PVA (polyvinyl alcohol). The test was performed with two groups of electrodes: (a) Electrodes treated with DNase buffer: here the researchers used only the buffer, that is, the solution used to maintain the ideal pH and salinity conditions, but without the active DNase enzyme. This serves as a control, because it should not degrade the DNA. (b) Electrodes treated with active DNase: in this case, the electrodes were exposed to the DNase enzyme, which has the function of degrading DNA. If the DNA is accessible (not protected or already degraded), the DNase will cut it and this will be reflected in the change in the electrical signal measured by the SWV technique. In short, the figure compares how the electrodes behave after two weeks of storage: one group was simply “rinsed” (control), while the other had the DNA actually attacked by the enzyme, to see if the DNA was still there and functional. If the PVA coating protects the DNA well, it will still be present and will be cut by the DNase, and this will be detected by the SWV.

According to Ariel Furst, professor of chemical engineering at MIT and one of the project leaders, the goal is to make this type of diagnosis accessible to everyone, especially where there are no clinics, laboratories or doctors nearby. “We want people to be able to test for diseases at home, without having to rely on a hospital,” she said.

This technology represents a huge step towards a more democratic, portable and preventive medicine, with disposable and durable sensors capable of detecting diseases early, without requiring specialists, expensive laboratories or refrigeration. This is science making diagnosis accessible and saving lives, wherever they are.

READ MORE:

Polymer Coating for the Long-Term Storage of Immobilized DNA

Xingcheng Zhou, Jessica Slaughter, Smah Riki, Chao Chi Kuo, and Ariel Furst

ACS Sensors. June 30, 2025 

https://doi.org/10.1021/acssensors.5c00937

Abstract: 

As healthcare systems worldwide demand early disease detection and personalized medicine, electrochemical biosensors stand out as a promising technology to meet these demands due to their sensitivity, selectivity, and rapid response. Specifically, DNA-based electrochemical biosensors are versatile and have been used to identify biomarkers of various infectious diseases. However, there is a significant gap between laboratory-scale proof-of-concept systems and commercially viable technologies. Commercialization of such sensors faces many challenges, with one of the most important being the stability and shelf life of the immobilized DNA. Surface-associated DNA faces thermal degradation, structural changes, and oxidation of tethering thiol groups, which causes DNA stripping from the surface. Currently, technology to support the long-term storage of these sensors at ambient temperatures is limited. Here, we report a novel method to preserve DNA in electrochemical biosensors through the application of a protective coating of poly(vinyl alcohol) (PVA). We show that with our PVA coating, the shelf life of dried, DNA-functionalized electrodes at ambient temperature is a minimum of 2 months. We further demonstrate that the protective capabilities of PVA extend to temperatures as high as 65 °C and that the biological relevance of the assay is not impacted by the coating. Our simple approach to DNA protection supports our understanding of how the electrode interfaces with biomolecules and facilitates biosensor scaling and commercialization.