New sensors track dopamine in the brain for more than a year

Tiny probes could be useful for monitoring patients with Parkinson’s and other diseases.

MIT neuroscientists have devised a way to measure dopamine in the brain for more than a year, using microfabricated sensors that are so tiny they don’t lead to the formation of scar tissue.
MIT neuroscientists have devised a way to measure dopamine in the brain for more than a year, using microfabricated sensors that are so tiny they don’t lead to the formation of scar tissue.

Dopamine is an organic chemical of the catecholamine and phenethylamine families that plays several important roles in the brain and body. Dopamine deficiency is often related to Parkinson’s disease, depression, and schizophrenia.

MIT scientists have now come up with a new sensor that can measure dopamine in the brain. Scientists believe that the sensor could help them to learn much more about its role in both healthy and diseased brains.

To develop a sensor that can be accurate over long periods of time, the researchers had to make sure that it would not provoke an immune reaction, to avoid the scar tissue that interferes with the accuracy of the readings.

The MIT team found that their tiny sensors were nearly invisible to the immune system, even over extended periods of time. After the sensors were implanted, populations of microglia (immune cells that respond to short-term damage), and astrocytes, which respond over longer periods, were the same as those in brain tissue that did not have the probes inserted.

During the study, scientists implanted three to five sensors per animal, about 5 millimeters deep, in the striatum. They took readings at regular intervals, in the wake of fortifying dopamine discharge from the brainstem, which goes to the striatum. They found that the estimations stayed predictable for up to 393 days.

Scientists noted, “If developed for use in humans, these sensors could be useful for monitoring Parkinson’s patients who receive deep brain stimulation. This treatment involves implanting an electrode that delivers electrical impulses to a structure deep within the brain. Using a sensor to monitor dopamine levels could help doctors deliver the stimulation more selectively, only when it is needed.”

Michael Cima, the David H. Koch Professor of Engineering in the Department of Materials Science and Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research, and Rober Langer, the David H. Koch Institute Professor and a member of the Koch Institute, are also senior authors of the study. MIT postdoc Helen Schwerdt is the lead author of the paper, which appears in the Sept. 12 issue of Communications Biology.