Implanted sensors

Developing chemical sensors that can be placed in the bloodstream or under the skin to continuously monitor oxygen, acidity (pH), or glucose levels is a major challenge for analytical chemists and biomedical engineers.

The problem is, the body responds to these foreign objects in ways that interfere with their ability to accurately measure blood chemistry. In the bloodstream, clots form on the surface of implanted sensors or blood vessels contract around them. Sensors implanted under the skin may become walled off by cells that flock to the site as part of the inflammatory response.

A University of Michigan team that previously demonstrated improved accuracy with intravascular sensors that were coated with nitric oxide-releasing polymers has promising preliminary results with a new strategy: creating polymer coatings that generate nitric oxide from components already in the blood.

"The idea we had, when we started working on this problem about eight years ago, was to try to mimic what occurs in the human body to prevent clotting on the walls of your own blood vessels," said U-M chemistry professor Mark Meyerhoff.