Recently, researchers demonstrated 3D printed neurons that can communicate with brain cells, opening up new possibilities in the field of human-machine interfaces. What challenges do human-machine interfaces face, what did the researchers develop, and why could this be the future of brain-based control?
What Challenges do Human-Machine Interfaces Face?
For the longest time, researchers and engineers have been fascinated by human-machine interfaces (HMIs). Such systems would allow humans to control machines with their intents and minds, not only helping to augment what man can do, but potentially opening up the possibilities to countless futures including full VR immersion, AR, and advanced prosthesis.
But creating such systems has proven to be immensely difficult, and while great strides have been made, we are still a long way from being able to create a reliable HMI. One of the biggest challenges faced is trying to detect brain waves non-invasively. While electrodes can be placed directly onto the surface of the brain, doing so requires surgery, meaning that such a system is not reversible, and thus, dangerous should something go wrong.
Another option is to place electrodes around the skull, but while this is somewhat more practical, it still suffers from numerous issues. Firstly, the resolution of such sensors is generally extremely poor, meaning that only the most basic controls can be detected. Secondly, the sensitivity of such sensors often sees them react to environmental stimuli, thereby producing false positives.
Electrodes placed inside the skull can help to improve resolution, but even then, the density of such sensors is still incredibly low, meaning that only a handful of signals can be recorded. Worse, trying to connect to every single neuron in the brain is simply not possible, meaning that any interface would likely be limited to specific areas of the brain.
Finally, even if electrodes are placed inside the brain, the body often rejects foreign objects, causing serious complications. This can see patients require numerous medications, which themselves carry side effects. Furthermore, the use of implanted electrodes can also introduce serious hygiene issues, making them difficult to maintain and monitor.
Researchers Create 3D Printed Neurons That Can Communicate with Brain Neurons
Recently, researchers at Northwestern University published a paper regarding 3D printed neuron-like structures that are able to send signals to real brain cells, and receive responses. While this may not seem like a major development, it is actually a significant step forward in the field of bioprinting, as it demonstrates how basic communication between artificial and biological systems can be achieved.
One of the biggest challenges faced with modern bioprinting technologies is that while they are able to print out biological structures, they are rarely able to make those structures function like real tissue. In the case of neurons, it is generally believed that neurons need to be connected to other neurons to be useful, and while this has been achieved, it has never been done with a 3D printed structure.
To achieve their goal, the team turned to aerosol jet printing, which is able to print nanoscale features. The printed structures were made from various materials including molybdenum disulfide and graphene, and printed onto flexible polymer substrates.
Once printed, the researchers placed their 3D printed neurons alongside living mouse brain cells, and were able to trigger responses from the living cells via the 3D printed neurons. At the same time, the 3D printed neurons were also able to receive signals from the living cells, thereby creating a two-way communication channel.
This two-way communication is significant because it shows that artificial neuron-like devices can not only stimulate but also respond to biological neural activity in real time. The printed devices mimic basic neural signaling, bridging the gap between synthetic electronics and living tissue at a cellular level.
Such hybrid systems offer new opportunities for research into how the brain processes information, as well as for building neuromorphic devices that emulate the brain's efficiency and adaptability. According to the researchers, the ability to print such neurons not only helps with the development of neuromorphic computing, but also for future brain-machine interfaces.
Could this be the Future of Human-Machine Interfaces?
There is no doubt that what the researchers have demonstrated is truly brilliant. Not only is it the first time that a 3D printed structure has been able to interface with neurons, but it is able to do so in a natural manner, without the need for electrodes penetrating cell structures and causing damage. Of course, this is still in the early days, and what the researchers have developed is nowhere near a practical device. However, that doesn’t mean that it won’t be the key to future HMIs.
For example, it is possible that future 5D printers (advanced robotic arms with extrusion systems) could be designed to print structures directly onto brains, providing a connection interface between a brain and some external system. This would eliminate the need for surgeons to insert probes into the brain, thereby reducing risk and recovery time.
It is also possible that such structures could be printed onto the brain of a robotic system, whereby a trained neural network is able to control the robot via thought alone. Again, this would eliminate the need for a mechanical interface between the brain and the robot, thereby creating a truly organic connection.
The possibilities that the researchers have demonstrated are endless, and only time will tell if this really is the future of brain interfaces.
