How can we make viable neural interfaces that last a lifetime?
Neurotechnology has the potential to provide a greater understanding of the structure and function of the complex neural circuits in the brain, as well as impacting the field of BMI to bring neuroprosthetic systems into the clinical realm.
Clinically-viable neurotechnologies that last a lifetime should be able to withstand a variety of biotic and abiotic effects that lead to performance degradation at the electrode-tissue interface. Moreover, these technologies should be wireless, require minimum power, and support large-scale bidirectional dataflow, i.e., “reading” and “writing” from/to the brain. In many cases, these systems will be fully implantable in the intracranial space as well as have batteryless operation. They should also be modular enough to allow the measurement and stimulation of different types of neural signals across different spatio-temporal scales.
In collaboration with Berkeley colleagues Michel Maharbiz, Jan Rabaey, Elad Alon, and Rikky Muller we have developed a number of unique technologies that have considerably advanced the state-of-the-art in BMIs. These include flexible sensor arrays, ultra-low power and low noise data acquisition channels, wireless powering of and communication with miniature-implanted devices, and complete system integration.
Vanishingly small neural interfaces
The highlight of our neurotechnology efforts with Michel Maharbiz is Neural Dust, a technology platform for wireless power and communication with implantable, extreme miniature sensors using ultrasound.
In essence, the technology consists of a millimeter-size implantable sensor that can be inserted deep into the body, such as in a particular nerve or organ, through a minimally invasive procedure. Neural dust uses ultrasound sent from an external device to receive power and communicate via backscatter real-time information such as electrophysiological data, pH, pressure, temperature, and oxygen levels from the body. Since ultrasound goes through the body like a charm, we only need to use minuscule amounts of power to energize the device and receive information from it.
For applications in cortical/subcortical BMIs, our goal is to achieve completely untethered recording through a large number of unanchored, free-floating miniature (< 100 µm3) motes. Overall, the long-term technology vision is to build multiple high bandwidth channels with the human body.
Recent collaborative efforts led by the Muller and Maharbiz groups have expanded the Neural Dust platform with electrical stimulation capabilities, resulting in StimDust. StimDust is the smallest volume, most efficient wireless nerve stimulator to date, capable of stimulating major therapeutic targets in the peripheral nervous system.
In the Fall of 2017, Michel Maharbiz and Jose Carmena co-founded iota Biosciences, a startup to commercialize the neural dust technology platform. iota aims to empower the future of bioelectronic medicine, transforming how the world monitors and treats disease.