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Tuesday, March 28, 2017

“I looked at my watch and saw it was time to go”

URI chemical engineering professor researches sensors to detect cancer
Image result for biomarkersIn the fight against cancer, early detection is crucial. Early detection means looking for so-called “biomarkers’’ that signal the start of cancer, often decades before the symptoms of the disease surface.

While knowing what to look for is a complicated process, looking for changes in the biomarker is a much harder problem. 

A new technique reported this week in the journal Nature Biomedical Engineering by University of Rhode Island Chemical Engineering Assistant Professor Daniel Roxbury and researchers from Memorial Sloan Kettering Cancer Center features an implantable sensor that can detect a wide range of clinically relevant biomarkers—both in biofluids from people and from live animals.

MicroRNA, or miRNA, which is a nucleic acid like DNA, is present in plants and animals. Out of the thousands of identified miRNA sequences, a subset is highly elevated in a number of human cancers.

These potential biomarkers can be found in blood, urine and saliva, and detecting them is a high priority for biomedical researchers. Methods to detect miRNA, from a blood test, for example, require going to a clinic and are limited to a few measurements a year for the patients.

An ideal solution would enable patients to monitor cancer biomarkers from the convenience of their own home and alert a doctor when miRNA levels start to change.

To accomplish this goal, Roxbury and the other researchers used carbon nanotubes—tiny needle-like hollow cylinders that are 100,000 times smaller than a strand of human hair—to engineer these tiny nanobiosensors. They can easily be implanted under skin and are non-invasive compared to biopsies.

“We use fluorescent nanotubes that emit light in the near-infrared wavelength range,” says Roxbury. “We could detect a signal from deep within a mouse, where our sensor was inserted.”

The sensors work by changing the color, or wavelength, of light that they emit while in the presence of miRNA. Shifts in wavelength correspond to the quantities of miRNA in the environment. The sensor currently functions in biological fluids and animals.

The study, funded by the National Institutes of Health and the American Cancer Society, demonstrates that the sensors can be embedded several centimeters under the skin and imaged with the use of harmless infrared light.

While potential applications in humans are still some time away, the goal of developing a group of nanotube-based sensors to continuously monitor biomarkers, for detecting diseases as early as possible, is a significant step closer.

Roxbury, 31, joined URI eight months ago, where he leads the NanoBio Engineering Laboratory He received his bachelor of science degree and doctorate in chemical engineering from Lehigh University in Bethlehem, Pa.

He did postdoctoral work at Memorial Sloan Kettering Cancer Center in New York, where he was funded through an American Cancer Society Postdoctoral Fellowship. The focus of his work is in the development, characterization and implementation of carbon nanotube-based probes for bio-imaging and bio-sensing applications.

“We aim to create a user-friendly platform where patients can monitor themselves at home and automatically alert a physician,” says Roxbury. “This is the technology we need. The next stage would be to construct some kind of wearable device, maybe a wristwatch, that incorporates this technology. This is the long-term goal. It’s certainly a monumental step.”