A team of researchers from the Faculty of Engineering and IT at the University of Technology, Sydney (UTS) has developed a novel carbon-based biosensor that adheres to the skin of the face and head in order to detect electrical signals being sent by the brain. These signals can then be translated into commands to control autonomous robotics systems.
The highly scalable novel sensing technology overcomes three major challenges of graphene-based biosensing: corrosion, durability, and skin contact resistance. This is due to the structure of the sensor, which is made of epitaxial graphene – essentially multiple layers of very thin, very strong carbon – grown directly onto a silicon-carbide-on-silicon substrate.
“We’ve been able to combine the best of graphene, which is very biocompatible and very conductive, with the best of silicon technology, which makes our biosensor very resilient and robust to use,” says Professor Francesca Iacopi.
A biosensor is a device that measures biological or chemical reactions by generating signals proportional to the concentration of an analyte in the reaction and thus diagnosing diseases. Thanks to this, the appropriate treatment and therapy are selected. Graphene is a nanomaterial used frequently in the development of biosensors. However, to date, many of these products have been developed as a single-use application and are prone to delamination as a result of coming into contact with sweat and other forms of moisture on the skin.
In contrast, the new UTS biosensor can be used for prolonged periods and reused multiple times, even in highly saline environments – an unprecedented result. In addition, the new sensor has been shown to significantly reduce the so-called skin contact resistance, where non-optimal contact between the sensor and skin impedes the detection of electrical signals from the brain.
“With our sensor, the contact resistance improves when the sensor sits on the skin,” Professor Iacopi says. “Over time, we were able to achieve a reduction of more than 75% of the initial contact resistance. This means the electric signals being sent by the brain can be reliably collected and then significantly amplified, and that the sensors can also be used reliably in harsh conditions, thereby enhancing their potential for use in brain-machine interfaces.”
This research is part of a larger collaboration to investigate how brainwaves can be used to command and control autonomous vehicles. If successful, the research will produce miniaturized, customized graphene-based sensors that can be applied in defense environments and beyond.