Carbon nanotube sensors could aid diabetic patients

Science has produced a range of nanomaterials in recent years with abilities that are highly useful to human health, including screening for toxins and monitoring levels of vital chemicals. But before the materials can be useful, it has to be possible to insert them into the body without the immune system attacking and destroying them.

MIT researchers published a paper (subscription required) this week describing sensors they created that could last in the human body for up to a year. The nanosensors are the first to have the ability to survive for such a long time.

The sensors are made from carbon nanotubes—minute tubes of rolled-up sheets of carbon atoms measuring just an atom thick. Carbon sheets are good at capturing individual molecules , which makes them excellent sensors. The researchers found that when they combined the nanotubes with different molecules, they could detect specific chemicals implicated in human health.

The first sensor the researchers built detects nitric oxide, which may play a role in cancer development. Using nanotubes to detect it could provide more information on the role NO plays in healthy vs. cancerous cells. The researchers are also interested in developing a sensor that detects glucose levels, which could be implanted in a diabetic patient’s body and provide a finger-prick-free system to monitor glucose and insulin levels.

So far, the researchers have tested the sensor under mice’s skin, where it worked for 400 days. While the body generally rejects foreign objects by pushing them out through the skin, the sensor was wrapped in an algae-based plastic gel that protected it from the body’s immune system.

Eventually, the researchers think similar sensors could be used to monitor inflammation and pick up on a person’s body rejecting an implanted device.