Indian-American scientist develops paper diagnostic for cancer

Written by PTI | Washington | Updated: Feb 25 2014, 21:41pm hrs
In a breakthrough, an Indian- American scientist at the prestigious MIT has developed a simple, cheap, paper test 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 Massachusetts Institute of Technology (MIT) announced yesterday.

This approach has helped detect infectious diseases, and the new technology allows non-communicable diseases to be detected using the same strategy, it said.

The technology, developed by MIT professor and Howard Hughes Medical Institute investigator 46-year-old Sangeeta Bhatia, relies on nanoparticles that interact with tumour proteins called proteases, each of which can trigger release of hundreds of biomarkers that are then easily detectable in a patient's urine.

"When we invented this new class of synthetic biomarker, we used a highly specialised instrument to do the analysis," says Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical Engineering and Computer Science.

"For the developing world, we thought it would be exciting to adapt it instead to a paper test that could be performed on unprocessed samples in a rural setting, without the need for any specialized equipment. The simple readout could even be transmitted to a remote caregiver by a picture on a mobile phone,"Bhatia said in a statement.

Bhatia, a member of MIT's Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science, is the senior author of a paper describing the particles in the Proceedings of the National Academy of Sciences published this week.

The paper's lead authors are graduate student Andrew Warren, postdoc Gabriel Kwong, and former postdoc David Wood.

In 2012, Bhatia and colleagues introduced the concept of a synthetic biomarker technology to amplify signals from tumor proteins that would be hard to detect on their own.

These proteins, known as matrix metalloproteinases (MMPs), help cancer cells escape their original locations by cutting through proteins of the extracellular matrix, which normally holds cells in place.

The MIT nanoparticles are coated with peptides (short protein fragments) targeted by different MMPs.

These particles congregate at tumor sites, where MMPs cleave hundreds of peptides, which accumulate in the kidneys and are excreted in the urine, it said.

In the original version of the technology, these peptides were detected using an instrument called a mass spectrometer, which analyzes the molecular makeup of a sample.

However, these instruments are not readily available in the developing world, so 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, MIT said.

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, the statement said.

"If one of these lines becomes visible, it means the target peptide is present in the sample. The technology can also easily be modified to detect multiple types of peptides released by different types or stages of disease," it said.

To help make that happen, the research team recently won a grant from MITs Deshpande Center for Technological Innovation to develop a business plan for a startup that could work on commercializing the technology and performing clinical trials.

Bhatia says 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, she would like to see it used for early detection throughout developing nations.

Such technology might also prove useful in the US, and other countries where more advanced diagnostics are available, as a simple and inexpensive alternative to imaging.

"I think it would be great to bring it back to this setting, where point-of-care, image-free cancer detection, whether its in your home or in a pharmacy clinic, could really be transformative," Bhatia said.

With the current version of the technology, patients would first receive an injection of the nanoparticles, then urinate onto the paper test strip.

To make the process more convenient, the researchers are now working on a nanoparticle formulation that could be implanted under the skin for longer-term monitoring, the MIT said.