Nanotubes Boost Biosensors for Faster Medical Diagnostics

Carbon nanotube illustration (National Science Foundation)

Researchers at Oregon State University in Corvallis have adapted carbon nanotubes to increase the speed of biological sensors that can reduce the time and costs for medical lab tests. The team led by physics professor Ethan Minot published their findings last month in the journal Lab on a Chip (paid subscription required).

Carbon nanotubes are long, hollow cylindrical carbon structures at nanoscale size, where one nanometer equals one billionth of a meter. Because of their near-molecular size and sensitivity, carbon nanotubes have unique mechanical, optical, and electronic properties.

For diagnostics, carbon nanotubes can help detect a protein on the surface of a sensor. When in contact with a protein, the nanotubes change their electrical resistance. The extent of this change in resistance can then be measured to determine the presence of a particular protein, for example serum protein biomarkers that can indicate breast cancer.

The OSU team’s contribution, funded by the U.S. Army Research Laboratory, was a protein repellent coating to keep proteins from sticking to other surfaces. This coating acted as a lubricant on the nanotube that increased the speed of a sensor by 2.5 times. Minot and colleagues believe this technology can be applied to a variety of microfluidic based biosensors.

Further work is needed to improve the selective binding of proteins, say the researchers, before the technology is ready to develop into commercial biosensors. But Minot believes the discovery can lead to faster and less expensive point-of-care lab tests that now take days and require trained off-site technicians.

“With these types of sensors, it should be possible to do many medical lab tests in minutes, allowing the doctor to make a diagnosis during a single office visit,” says Minot. “This approach should accomplish the same thing [as current lab methods] with a hand-held sensor, and might cut the cost of an existing $50 lab test to about $1.”

Read more: Patent Granted for Nanotech Medical Diagnostic Technology

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