Eye drop or brain biopsy? Someday soon, those could be choices to the same end. Philip Liu, an HMS associate professor of radiology at Massachusetts General Hospital, has developed a gene–detecting brain probe that can be administered using a simple eye drop.
The technology consists of a standard MRI probe—a tiny substance, just 30 nanometers in diameter, detectable using magnetic resonance imaging—attached to a DNA strand. When administered, the solution flows from the eye through the blood–brain barrier and into brain cells. It binds only in cells with similar strands of messenger RNA, allowing selective targeting and magnetic resonance imaging of genetic activity.
The probe has proved effective in mice with leaky blood–brain barriers. In mice without such leaks, Liu has delivered the drug using a blood–brain barrier bypass similar to cortical and lumbar punctures.
The technology is based on the premise that specific gene activity in brain cells plays a role in cancer, neurodegenerative diseases, drug addiction, and mental health. Liu’s noninvasive probe could be tuned to detect specific forms of cancer, brain changes that might indicate Alzheimer’s or Parkinson’s disease, or stem cell activity.
“We hope to bring expertise in molecular biology into medicine without relying on biopsies,” says Liu, who is working to expand the technology’s applications.