Implant delivers drugs to brain
WASHINGTON, D.C. — Scientists have created a hair-thin implant that can drip medications deep into the brain by remote control and with pinpoint precision.
Tested only in animals so far, the device, if it pans out, could mark a new approach to treating brain diseases — potentially reducing side-effects by targeting only the hard-to-reach circuits that need care.
“You could deliver things right to where you want, no matter the disease,” said Robert Langer, a professor at the Massachusetts Institute of Technology whose biomedical engineering team reported the research.
Stronger and safer treatments are needed for brain disorders ranging from depression to Parkinson’s. Simply getting medications inside the brain, past what’s called the blood-brain barrier, is a hurdle. It’s even harder to reach its deepest structures.
Pills and IV drugs that make it inside trigger side-effects as they wash over entire regions of the brain. Doctors have tried inserting tubes into the brain to pump drugs closer to their targets, but that risks infection and still isn’t accurate enough. The most targeted success to date is a cancer treatment, a wafer placed on the site of a surgically removed brain tumour that oozes out chemotherapy.
The MIT team’s approach is a customizable deep-brain implant that can deliver varying doses of more than one drug on demand.
The researchers constructed two ultra-thin medication tubes and slid them into a stainless steel needle that’s about the diameter of a human hair. The needle, built as long as needed to reach the right spot, gets inserted through a hole in the skull into the desired brain circuitry. An electrode on the tip provides feedback, monitoring how the electrical activity of targeted neurons changes as the medication is delivered.
The needle is hooked to two small, programmable pumps that hold the medications. The plan is to thread the pumps somewhere under the skin for a fully implantable system, dubbed MINDS for miniaturized neural drug delivery system. The pumps can be refilled with an injection, and if more than two drugs are needed, additional reservoirs could be added, as in a printer ink cartridge, Langer said.
Researchers carried out experiments on rats and a monkey.
“There’s a lot of therapeutic potential for this,” said Tracy Cui, a bioengineering professor at the University of Pittsburgh, who wasn’t involved with the MIT study, but is also developing this kind of technology.