SCIENCE TODAY:IMAGINE peering inside a brain and watching the chemical dances behind events like learning or degeneration. An Irish scientist has come up with a new invention to provide such a glimpse – a tiny sensor implant that measures levels of brain chemicals in real time, writes CLAIRE O'CONNELL
The approach could boost analysis in brain research and help improve drug development for a range of conditions, including Alzheimer’s, depression and schizophrenia.
“It’s a chemical sensor, an electrode – a piece of platinum wire,” explains Prof John Lowry, head of chemistry at NUI Maynooth, who has developed and tested the system. “You cut a clean surface at the end and you have this nice disc, which is pure platinum.”
That disc provides a platform for some “fancy chemistry” to measure a range of chemicals in the brain, including glucose, oxygen and various biochemicals involved in relaying messages between brain cells.
Currently, scientists can measure brain chemicals in animals by taking microdialysis samples, but that only provides a snapshot of what’s going on, says Prof Lowry. “There’s a limitation in that it takes about 20 minutes to get a data point. And when you are interested in behavioural studies that time resolution is poor. But that approach is widely used in the pharmaceutical industry.”
Meanwhile techniques like functional MRI offer real-time images of brain function, with regions lighting up as blood flow changes. But the cumbersome equipment leaves little scope for the subject being examined to move around freely as they carry out tasks.
Instead, the implanted sensor generates electrical signals that can be relayed wirelessly to a computer, allowing scientists to monitor levels of chemicals in particular brain regions as tasks are being performed. “With the sensor you can look at levels as they are going about their business,” says Prof Lowry.
“The idea is that we can implant all the different sensors in the same animal and then try and get an understanding of how the molecules are interacting together. So one goes up, one goes down – what’s the relationship. That should open the door to understanding disease states.”
MONITORING THElevels of key chemicals in the brain could open the floodgates for building up knowledge about an array of conditions. "When you look at the molecules that we know are implicated in disease states, there is a lot of overlap – compounds like glutamate, dopamine, they are involved in schizophrenia, depression, Parkinson's and Alzheimer's," he says.
“With our sensors, because we have selectivity for these molecules, it’s not a huge jump for us to investigate different disease states.”
Prof Lowry and his team have been interacting with pharmaceutical companies, including Eli Lilly, and the sensors have excited much interest. “We had been getting orders from companies asking us to send them sensors and we were struggling to meet that as the orders were getting bigger,” he says.
So NUI Maynooth took out patents on the intellectual property and have created a company, BlueBox Sensors, to manufacture the devices, particularly targeting drug discovery.
The sensors will allow pharmaceutical companies to get a better handle on how drug candidates act in the brain, and will also help them to ditch compounds early in the testing process if they don’t have the appropriate effects, says Dr John Scanlan, director of commercialisation at NUI Maynooth.
“If they think a [drug] compound modulates serotonin in a particular part of the brain, until now they’d had no way of knowing how to do that in real time, to know whether it’s efficacious,” he says. “Also, if they take a [drug] compound from an initial 10,000 and they are going to end up with one, they would like to dump the other 9,999 as early as possible. That’s called early attrition and this sensor approach allows that.”
The new spin-out company will keep the expertise rooted at NUI Maynooth and the sensor devices are to be manufactured in Galway, explains Dr Scanlan.
“It has the potential to create a huge number of jobs in Ireland and the technology and brains behind it will be based here.”