They could also help doctors better treat patients with brain disorders or injuries, Liu says. Although gliosis performs a valuable function by isolating damaged tissue, it also hinders the brain's repair mechanisms. "If we know gliosis is happening," Liu says, gliosis inhibitors could be administered "to allow more time for repair." The probes could also be used to deliver drugs directly to damaged regions of the brain, he adds.

"In theory, it's a great concept," says Ahmet Hoke, an associate professor of neurology and neuroscience, also at Johns Hopkins. However Hoke, who was not involved in the work, wants to see more proof that the probe is specific to gliosis.

Like Hoke, Ausim Azizi, a professor of neurology at Temple University School of Medicine, has doubts about the specificity of the probe, but he says the technique has the potential to be a useful diagnostic tool, because it could distinguish between gliomas--brain tumors that involve glial cells--and other types of tumors. However, Azizi wonders if the eyedrop method will be able to deliver enough probes to the human brain to be helpful in diagnosis.

Because the technique took advantage of breaches in the blood-brain barrier created in mice using fairly harsh techniques such as brain punctures, oxygen starvation, and electric shock, Stins says, "it remains to be seen to what extent breaches in the blood-brain barrier in human diseases will be enough to deliver this gene probe with the specificity they claim they have. They've got their work cut out for them."