A simple, cheap, paper test has been developed that could improve cancer diagnosis rates and help people get treated earlier. The diagnostic, which works much like a pregnancy test, could reveal within minutes, based on a urine sample, whether a person has cancer. The technology relies on nanoparticles that interact with tumor proteins called proteases, each of which can trigger release of hundreds of biomarkers that are easily detectable in urine.
This approach has helped detect infectious diseases, and the new technology allows non-communicable diseases to be detected using the same strategy. The nanoparticles are coated with peptides (short protein fragments) targeted by different matrix metalloproteinases (MMPs). These particles congregate at tumor sites, where MMPs cleave hundreds of peptides, which accumulate in the kidneys and are excreted in the urine.
The researchers adapted the particles so they could be analyzed on paper, using an approach known as a lateral flow assay — the same technology used in pregnancy tests. To create the test strips, the researchers first coated nitrocellulose paper with antibodies that can capture the peptides. Once the peptides are captured, they flow along the strip and are exposed to several invisible test lines made of other antibodies specific to different tags attached to the peptides. If one of these lines becomes visible, it means the target peptide is present in the sample.
The technology would likely first be applied to high-risk populations, such as people who have had cancer previously, or had a family member with the disease. Eventually, it could be used for early detection throughout developing nations. Such technology might also prove useful in the United States and other countries where more advanced diagnostics are available, as a simple and inexpensive alternative to imaging.