Wireless Recording in the Peripheral Nervous System with Ultrasonic Neural Dust

Abstract

The emerging field of bioelectronic medicine seeks methods for deciphering and modulating electrophysiological activity in the body to attain therapeutic effects at target organs. Current approaches to interfacing with peripheral nerves and muscles rely heavily on wires, creating problems for chronic use, while emerging wireless approaches lack the size scalability necessary to interrogate small-diameter nerves. Furthermore, conventional electrode-based technologies lack the capability to record from nerves with high spatial resolution or to record independently from many discrete sites within a nerve bundle. Here, we demonstrate neural dust, a wireless and scalable ultrasonic backscatter system for powering and communicating with implanted bioelectronics. We show that ultrasound is effective at delivering power to mm-scale devices in tissue; likewise, passive, battery-less communication using backscatter enables high-fidelity transmission of electromyogram (EMG) and electroneurogram (ENG) signals from anesthetized rats. These results highlight the potential for an ultrasound-based neural interface system for advancing future bioelectronics-based therapies.

Toward Bioelectronic Medicine—Neuromodulation of Small Peripheral Nerves Using Flexible Neural Clip

“…The total size of the wireless FNC was 3 mm × 5 mm, which is significantly smaller size than currently developed neural interfaces and comparable with neural dust (Figure 6a) 17. This tiny and wirelessly powered FNC could be reliably implanted on the small visceral pelvic nerve deeply located in the body and providing remote modulation of micturition in rats.…”

“…These challenges include (i) for the autonomic nervous system, complex innervation of the organs or muscles, rendering precise control of specific functions challenging; (ii) quick and mechanically secure implantation which is an important consideration in the presence of physiological motion such as respiratory and cardiovascular movements; and (iii) considerable compliance and flexibility from the neural interfaces since nerves are highly compliant and associated with moving organs. Additionally, the integration of NIT with wireless powering by either ultrasound17 or electromagnetic powers18 is a promising direction for future bioelectronic medicine.…”

Blind parallel interrogation of ultrasonic neural dust motes based on canonical polyadic decomposition: A simulation study

“…A crucial observation is now that, due to the ∆-periodicity of the beam patterns, each matrix R k (t) for each neural sampling time t ∈ {0, ∆, 2∆, ...} is exactly the same complex-valued rank-1 matrix up to a real-valued amplitude scaling with V k (t), i.e., 3 In section IV, we will investigate the influence of noise.…”

“…In [2] the 'neural dust' (ND) concept has been introduced, consisting of a wireless ultrasonic backscatter system for communicating with implanted passive sensor devices, referred to as ND motes (NDMs). Very recently, a ND system has been validated in-vivo to record electro-physiological activity in the peripheral nervous system of a rat [3]. Although [3] uses mm-scale NDMs, the ND concept has been shown to be scalable to sub-mm scale, which one day could allow to chronically and wirelessly record electro-physiological signals within the brain cortex at a micro-scale pitch [2].…”

“…Very recently, a ND system has been validated in-vivo to record electro-physiological activity in the peripheral nervous system of a rat [3]. Although [3] uses mm-scale NDMs, the ND concept has been shown to be scalable to sub-mm scale, which one day could allow to chronically and wirelessly record electro-physiological signals within the brain cortex at a micro-scale pitch [2]. To this end, a large number of free-floating NDMs is implanted in the cortex at a 2mm depth in a grid with a 100 µm pitch, in which each NDM measures action potentials or 'spikes' generated by nearby neuron cells [2], [4].…”