November 4, 2013
New Implantable Sensor Could One Day Monitor Glucose Levels
Lee Rannals for redOrbit.com - Your Universe Online
In a paper published in the journal Nature Nanotechnology, scientists describe a newly developed sensor that is able to monitor nitric oxide in living animals and could potentially become a valuable asset to diabetic patients in the future.Nitric oxide is considered to be one of the most important signaling molecules in living cells, but in many cancerous cells levels are perturbed. Scientists have needed a new tool to help measure this molecule in the body and in real time.
The new sensor can be implanted under the skin and used to monitor inflammation, which is a process that produces nitric oxide. These sensors can also be adapted to detect other molecules, such as monitoring glucose or insulin levels in diabetic patients.
“So far we have only looked at the liver, but we do see that it stays in the bloodstream and goes to kidneys. Potentially we could study all different areas of the body with this injectable nanoparticle,” Nicole Iverson, who led the study, said in a statement.
Researchers have previously found that carbon nanotubes can detect nitric oxide if the tubes are wrapped in DNA with a particular sequence. Scientists in the latest study were able to modify the nanotubes to create two different types of sensors, including one that can be injected into the bloodstream for short-term monitoring and one that is able to be implanted under the skin for long-term.
Iverson attached a biocompatible polymer that inhibits particle-clumping in the bloodstream in order to make the particles injectable. The researcher found that when injected into mice, the particles flow through the lungs and heart without causing any damage.
The longer-term sensor consists of nanotubes embedded in a gel made from alginate. When this gel is implanted under the skin of the mice, it stays in place and remains functional for 400 days. This sensor could be used to monitor cancer or other inflammatory diseases, or detect immune reactions in patients with artificial hips or other implanted devices.
James Tour, a professor of chemistry at Rice University’s Smalley Institute for Nanoscale Science and Technology, pointed out that the new sensors merge the fields of chemistry, polymers, nanomaterials, biology, medicine, and optics.
“The selectivity and sensitivity are indeed impressive,” Tour, who was not a part of the study, said in a statement.
The team is now working on adapting the technology to help detect glucose by wrapping different molecules around the nanotubes. Diabetic patients have to prick their fingers multiple times a day to take blood glucose readings. However, if Iverson and colleagues are able to modify this sensor then it would not only offer real-time glucose monitoring, but it could also provide relief from the burden of constantly pricking one’s finger.
“The current thinking is that every part of the closed-loop system is in place except for an accurate and stable sensor. There is considerable opportunity to improve upon devices that are now on the market so that a complete system can be realized,” Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT, said in a statement.