Device for neuroprosthetics with autonomous tunable actuators
Inventors
Muthuswamy, Jitendran • Palaniswamy, Sivakumar
Assignees
National Institutes of Health NIH • Arizona State University Downtown Phoenix campus
Publication Number
US-11672486-B2
Publication Date
2023-06-13
Expiration Date
2036-04-22
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Abstract
A microelectromechanical device and method for neuroprosthetics comprises microactuators and microelectrodes. The microelectrodes are to be positioned in a nerve bundle and bonded with the microactuators through an interconnect. The position of each of the microactuators can be individually tuned through control signals so that the microelectrodes are implanted at desired positions in the nerve bundle. The control signals are transmitted to the microactuators and generated with a open-loop or closed-loop control scheme that uses signals acquired by the microelectrodes from the nerve bundle as feedback.
Core Innovation
The invention provides a microelectromechanical system (MEMS) device and method for neuroprosthetics comprising tunable microactuators and microelectrodes that can be individually tuned through control signals. These microelectrodes are positioned and microbonded in a nerve bundle via interconnects, allowing their position to be precisely adjusted to desired locations within the nerve bundle. Control signals for the microactuators are generated using an open-loop or closed-loop control scheme, which uses signals acquired from the nerve bundle by the microelectrodes as feedback to optimize electrode positioning.
The device addresses the significant problems of stability and specificity in current neural interface and neuromodulation technologies. Existing implantable neuroprostheses lack the required stability and specificity for targeting particular sensory or motor neurons within a nerve bundle, which is critical for achieving reliable and precise functional states of target organs, especially in chronic conditions. The MEMS device overcomes these challenges by enabling autonomous, precise tuning of actuator positions to target specific neurons.
Key features of the invention include (i) MEMS microactuators that move sensors such as microelectrodes or nanoelectrodes individually and precisely within nerve bundles, (ii) microscale or nanoscale bonding techniques that electrically and mechanically integrate microactuators and microelectrodes via conductive interconnects, and (iii) a closed-loop autonomous control scheme that uses nerve signals as feedback to accurately position microelectrodes to stimulate or record from optimal locations within nerve fibers. Additionally, wireless telemetry allows transmission of neurophysiologic data, stimulation signals, and control signals, facilitating system integration and scalability.
Claims Coverage
The claims cover inventive features related to a method for positioning sensors within nerve bundles using MEMS devices, focusing on sensor construction, implantation, signal feedback, control, and neural blocking.
Integrated sensor structure with microelectrode, implant, and interconnect
The sensor comprises an electrode portion made of polysilicon, an implant portion made from stainless steel, and an interconnect extending the electrode portion into the implant portion to electrically and structurally bond these components.
Implantation and positioning within nerve bundle using signals
Implanting the sensors into the nerve bundle and moving the distal end of the implant portion upwardly or downwardly within the nerve bundle responsive to received neurophysiologic and electrical impedance signals to optimize the received signals.
Closed-loop control using neurophysiological and auxiliary signals
Generating control signals with a closed-loop control scheme based on neurophysiological signals and optionally other signals such as current consumption, stress, and strain in surrounding tissue, to adjust microactuator positions and optimize sensor placement.
Microelectrode and nanoelectrode as implant portions
Providing the implant portion configured as either a microelectrode or a nanoelectrode for neural interfacing.
Transverse implantation orientation with respect to microactuators
Implanting the implant portion of the sensors transversely to the nerve bundle while the MEMS microactuators are oriented parallel to the nerve bundle.
Use of guide tubes for nerve penetration and sensor emergence
Covering the implant portion with a guide tube that penetrates the nerve bundle and allows the implant portion to emerge from inside the tube to establish contact with neurons.
Enclosure and spatial bending of sensors for implantation
Enclosing the nerve bundle within a channel of the MEMS device and implanting bent or spatially bent sensors through guide tubes.
Blocking neural motor signals using alternating current
Using alternating current via the MEMS device to block neural motor signals within the nerve bundle.
These inventive features collectively provide a precise, autonomously tunable MEMS-based neuroprosthetic system enabling optimal sensor placement, signal acquisition, stimulation, and neural blocking within nerve bundles.
Stated Advantages
Improved stability and specificity in targeting individual motor or sensory neurons within nerve bundles for chronic neuroprosthetic applications.
Precise individual tuning of microelectrode positions to achieve or detect desired end-organ functional states reliably.
Closed-loop autonomous control scheme using neural signals as feedback to optimize electrode positioning and neural interfacing.
Wireless telemetry enables remote transmission of neurophysiologic signals, stimulation signals, and microactuator control signals.
Scalable MEMS microelectrode array system supporting multi-modal interfaces for various peripheral and visceral nerve targets.
Capability to block neural motor signals via high-frequency alternating current for functional neuromodulation.
Documented Applications
Controlling the urinary bladder via implantation on the pelvic plexus and tuning microelectrodes to optimize motor control and sensing.
Recording neurophysiologic signals and micro-stimulating nerves at optimal positions within nerve bundles.
Blocking neural motor signals in nerves using kilohertz frequency alternating currents for temporary conduction block.
Multi-modal interfacing applicable for visceral organ-specific targets or peripheral somatic pathways such as bronchial tone control, sensing airway resistance, sensing oxygen in the carotid body, controlling catecholamine secretion in adrenal medulla, and controlling upper extremity robotic prostheses.
Use in biomarker detection, central nervous system therapeutics, cyber-physical systems, medical diagnostics, brain-machine interfaces, gene and drug delivery, and implantable medical devices.
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