Implantable prosthetic interface could deliver sense of touch

An electronics breakthrough made by specialists at Belgian research group Imec has enabled the development of a prototype implantable chip that could enable future prosthetic devices to convey a sense of touch.

The chip has been developed through haptics research funded by DARPA in the US

Developed in collaboration with researchers at the University of Florida as part of the IMPRESS (Implantable Multimodal Peripheral Recording and Stimulation System) project funded by the DARPA’s HAPTIX program, the technology could ultimately help provide patients with sensory information by delivering precise electrical patterns to the wearer’s peripheral nerves.

Current prosthetic arm technologies work by reading signals from the wearer’s muscles or peripheral nerves to control electromotors in the prosthesis. However, these devices still don’t allow fine motor control or give patients a feeling of touch.

Commenting on the new chip Prof Rizwan Bashirullah, director of the University of Florida’s IMPRESS program said: “This effort aims to create new peripheral nerve interfaces with greater channel count, electrode density, and information stability, enabled largely by Imec’s technological innovation.”

Imec has now made a prototype ultrathin (35µm) chip with a biocompatible, hermetic and flexible packaging. On its surface are 64 electrodes, with a possible extension to 128. This high number of electrodes allows fine-grained stimulation and recording.

Through a needle attached to the chip, the package can be inserted and attached inside a nerve bundle, further increasing the precision of reading and stimulation compared to current technology, which has substantially fewer electrodes and is wrapped around the nerve bundle.

“Our expertise in silicon neuro-interfaces made Imec a natural fit for this project, where we have reached an important milestone for future-generation haptic prosthetics,” said Dries Braeken, R&D manager and project manager of IMPRESS at Imec. “These interfaces allow a much higher density of electrodes and greater flexibility in recording and stimulating than any other technology. With the completion of this prototype and the first phase of the project, we look forward to the next phase where we will make the prototype ready for long-term Implanted testing.”