Platinum–Iridium Microelectrodes from Advent Drive Progress in Neurochemical Sensing

Researchers at Maynooth University have developed advanced choline biosensors using platinum–iridium wire supplied by Advent Research Materials.
The sensors enable real-time monitoring of neurotransmitter activity in the brain, improving understanding of disorders such as Alzheimer’s.

The science made simple

Scientists at Maynooth University in Ireland wanted to understand how tiny messages travel around the brain. Our brains send these messages using special chemicals called neurotransmitters. One of them is acetylcholine, which helps us think, learn, and remember.

When the brain uses acetylcholine, it breaks down into another chemical called choline.
By measuring choline, scientists can tell how active the brain’s message system is.

To do this, they built a very small sensor—so small it can go inside a mouse’s brain without hurting it. The sensor is made from a thin wire of platinum and iridium, supplied by Advent Research Materials. The wire conducts electricity and helps turn chemical changes in the brain into tiny electrical signals.

The sensor was coated with an enzyme called choline oxidase. When choline touches it, a small electric current is made. By measuring that current, scientists can see when and how much choline is in the brain.

The team tested the sensor in mice and found it could work for weeks, showing how choline levels change during rest, activity, and when the mice were given certain medicines.

This helps scientists study brain problems like Alzheimer’s disease or memory loss, because they can now watch brain chemistry happening in real time.

Supporting innovation in neuroscience

At Maynooth University, researchers are redefining how brain chemistry is measured. Their latest work demonstrates a new class of miniaturised choline biosensors that use platinum–iridium wire from Advent Research Materials to achieve high sensitivity and stability in live animal studies.

These microsensors allow scientists to monitor neurotransmitter dynamics in real time, helping uncover how brain cells communicate and how this communication changes in conditions like Alzheimer’s, Parkinson’s, and schizophrenia.

The role of Advent’s platinum–iridium wire

The biosensors were built using 75 µm platinum–iridium wire supplied by Advent Research Materials.
This alloy was selected for its superior conductivity, corrosion resistance, and biocompatibility, essential for stable long-term performance in neural tissue.

The smaller 75 µm diameter—down from 125 µm in earlier designs—allowed the researchers to produce disc-shaped electrodes with a minimal footprint. This size reduction lowered tissue disruption during implantation while maintaining high electrochemical activity for precise signal capture.

Advancing choline detection in the brain

Each sensor was coated with choline oxidase, an enzyme that reacts with choline (a marker of acetylcholine metabolism) to form hydrogen peroxide.
The resulting electrochemical signal, measured through the Advent platinum–iridium wire, reflects real-time changes in cholinergic activity—key to learning, memory, and attention.

The team recorded continuous data from regions including the hippocampus and prefrontal cortex, detecting dynamic fluctuations in choline levels linked to pharmacological challenges, behavioural states, and circadian cycles.

Key findings

• The new design maintained excellent sensitivity and selectivity, even at smaller sizes.
• Sensors functioned reliably for weeks in vivo, enabling extended studies in freely moving mice.
• Responses correlated strongly with known physiological effects of drugs such as donepezil and scopolamine, validating accuracy.
• The technology also detected impaired choline release following selective neuronal damage, modelling neurodegeneration.

These results confirm that the modified platinum–iridium microelectrodes provide a powerful new tool for continuous, real-time neurochemical monitoring.

Applications and impact

This research highlights how high-purity platinum–iridium wire underpins breakthroughs in biosensor engineering and neuroscience.
The ability to track neurotransmitter activity at this scale could transform studies of cognitive function and accelerate drug discovery for neurological disorders.

Advent Research Materials continues to supply precision wires and foils for universities and research institutes developing biosensors, neural interfaces, and other microelectronic medical technologies.

Read the full study

This work was conducted by Paul G. Jones, Aoife Kelly, and colleagues at Maynooth University with international collaborators.
It was published in the European Journal of Neuroscience (November 2025) under the title:
“Development of a microelectrochemical choline biosensor for chronic in vivo monitoring of cholinergic neurotransmission in mice.”

Citation:
Jones, P.G., Kelly, A., et al. (2025). Development of a microelectrochemical choline biosensor for chronic in vivo monitoring of cholinergic neurotransmission in mice. Eur. J. Neurosci., 62(11), e16636.
DOI: 10.1111/ejn.16636