Image of chip
The new type of chip imitates the fundamental biology of nature’s best computer. (Credit: RMIT)

Researchers have developed a device that replicates the way the brain stores and loses information. The technology creates opportunities to better understand how the brain is affected by disorders that disrupt neural connections, such as Alzheimer’s disease and dementia. The technology can also be integrated into wearable electronics.

RMIT researchers drew inspiration from an emerging tool in biotechnology — optogenetics. Optogenetics allows scientists to delve into the body’s electrical system with incredible precision, using light to manipulate neurons so that they can be turned on or off. The new chip is based on an ultra-thin material that changes electrical resistance in response to different wavelengths of light, enabling it to mimic the way that neurons work to store and delete information in the brain.

The researchers, from the Functional Materials and Microsystems Research Group at RMIT, have also demonstrated the chip can perform logic operations — information processing — ticking another box for brain-like functionality. Developed at the Micro Nano Research Facility, the technology is compatible with existing electronics and has also been demonstrated on a flexible platform, for integration into wearable electronics.

Light is used to generate a photocurrent on the chip. Switching between colors causes the current to reverse direction from positive to negative. This direction switch, or polarity shift, is equivalent to the binding and breaking of neural connections, a mechanism that enables neurons to connect (and induce learning) or inhibit (and induce forgetting). This is akin to optogenetics, where light-induced modification of neurons causes them to either turn on or off, enabling or inhibiting connections to the next neuron in the chain.

To develop the technology, the researchers used a material called black phosphorus (BP) that can be inherently defective in nature. This is usually a problem for optoelectronics, but with precision engineering the researchers were able to harness the defects to create new functionality.