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Exploring the potential of mind control

In the early 1990s, the Foundation set about conceptualizing how lost motor function might be restored to the limbs of patients living with a spinal cord injury. When the connection between the mind and the muscle is severed, how might that link be reestablished? 

Early work on the project was supported by DARPA, the U.S. Defense Advanced Research Projects Agency, and initially undertaken in tandem with several universities. We leaned on our in-house expertise in two key areas—implantable devices, and miniaturized electronics—in order to develop a device concept which could, in theory, restore motor function in the extremities. We called it the  BION. 

‍The initial idea was fairly straightforward in theory, if exceptionally complicated in practice. A constellation of active electrodes, each one housed in a tiny biocompatible tube and implanted throughout a group of muscles, could be triggered to fire in concert, contracting and extending the muscles and producing movement in a limb. Each tube (or Bion) could be engineered to communicate with each other using radio frequencies—and similar radio frequencies could ultimately be used to power the devices, meaning no batteries would be required, although later we created a rechargeable battery-powered version. 

One concept, two distinct applications

As we continued to work through possible solution ideas, this initial technology concept began to split into two distinct avenues: a stimulating version, which could produce movement in cases of spinal cord injury, and a sensing version, which could interpret nerve impulses and relay signals to a robotic prosthetic in cases of limb loss.

Early on, we realized that the stimulating version of the Bion would be the most difficult to perfect of any project we had taken on. While the Bion constellation idea still has potential (and we continue work on variants of this project to this day), the incredible complexities of balance, muscle control, and coordination within the human body present enormous challenges to reproducing stable movement.

The sensing version of the BION, however, seemed a more actionable application of the technology. We turned our attention to designing and developing these sensing implants—tech which we now called “IMES,” an abbreviation for implanted myoelectric sensor.

A tiny ship in a bottle

As work on the IMES began, we were faced with our first challenge: how to practically visualize the tiny, complicated components that would need to fit into each implant. Luckily, at the Foundation, our team tends to think outside the box. One day Dr. Schulman, the Foundation’s first CEO, arrived at work with a giant printer, which he used to reproduce the circuit board’s miniature schematic in larger-than-life scale. With the IMES’s now-oversized circuitry plastered on the walls of the lab, our engineering team was able to walk around and immerse themselves in the complicated inner workings of the miniature device not much bigger than a pencil lead. This allowed for more practical consideration of how the IMES could be brought to life.

Then came the development complications—which are inevitable, when you’re trying to create something that’s never been done before. The familiar issue of materials came to the forefront early on in this project. Each IMES tube was to feature a ceramic body, since ceramic is a biocompatible material which also allowed radio frequencies to enter. However, each tube had to be capped with a conductive electrode made of pure platinum—and we had to figure out a way to permanently adhere platinum to ceramic in such a way as to prevent leaking or corrosion of the electronics housed within.

To solve the problem, the Foundation purchased a $1M computer-controlled, ultra-high vacuum braze furnace that was capable of fusing the materials together at a temperature of over 1000 degrees Celsius.

Then, the implant’s communication antenna needed to be painstakingly thought through. The antenna was a tiny, carefully coiled wire within the IMES tube, which required a precise number of coils at a very specific diameter and tension in order to resonate at the correct radio frequency. In the end, we ended up designing and building machinery in-house that would be able to create these precision coils in a standard repeatable way. 

Then the team wondered, once the tubes were inserted into muscle tissue, how do we get them out if it becomes necessary? Our engineers opted to include an eyelet on one version of the IMES cap which a surgeon could put a suture through—a lead line that could later be used to pull the tube from the muscle for simple removal as needed.