Scientists have developed minimally invasive brain probes that can selectively deliver drugs in-vivo and stimulate cells with light. The probes can be wirelessly controlled from a smartphone.

It is hoped that the probes will advance understanding of neurodegenerative disease by allowing the manipulation of brain circuits.

Delivering drug infusions into the brain has previously been extremely challenging, requiring invasive surgery which can result in inflammation. The new probes are made of a soft material, which reduces the risk of tissue damage, and were successfully implanted into mice brains. The probes use replaceable drug cartridges to achieve a constant supply of drug without the need for additional surgery.

The signal from the smartphone programme is wirelessly transmitted to the drug cartridges via Bluetooth. An electrical current then flows through the cartridge which causes the thermal expansion of the polymer layer inside. The volume increase in the polymer layer ejects the drug from the capsule and into the brain. The probes can be controlled from up to 100m away.

The smartphone programme can also control the selection of different colour LEDs on the probes. This allows specific wavelengths of light to be emitted selectively on certain areas of the brain, which can be used for the localisation of drug treatment and the photostimulation of brain cells.

This technology could both enhance our understanding of neurodegenerative diseases and enable targeted drug delivery to the brain.