Active Neural Interfaces for Bioelectronic Medicines
Lead Research Organisation:
University College London
Department Name: Electronic and Electrical Engineering
Abstract
Addressing the grand challenge of "frontiers of physical intervention" in the EPSRC healthcare technologies theme, this PhD research aims to develop smart neural interfaces for bioelectronic medicines, where electronic microchips interact with the nervous system directly for restoring lost body function or rebuilding a healthy balance of organ operation. Bidirectional closed-loop neural modulation will be implemented on the microchips using CMOS technology. By developing novel three-dimensional microfabrication techniques, the neural interface will be capable of not only highly selective and precise neural sensing and intervention, but also promotion of nerve regeneration in the case of nerve damage due to injury, disease or organ transplantation. This PhD study will explore new techniques in both ultra-low-power CMOS integrated circuit design and advanced micro-fabrication, and investigate device robustness and reliability for chronic implantation.
Organisations
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| EP/R513143/1 | 01/10/2018 | 30/09/2023 | |||
| 2237232 | Studentship | EP/R513143/1 | 01/10/2019 | 30/09/2023 | Maryam Habibollahi |
| Description | Vagus nerve stimulation (VNS), which is an accepted therapy for numerous neurological, inflammatory, and cardiac disorders, has recently shown benefits on the post-operation symptoms of heart transplant recipients (HTxR). The application of VNS requires a bidirectional neural interface which provides electrical stimulation of the nerve to elicit or prevent neural spikes, and to record valuable data from the neural fibres, helping us understand the treatment efficacy for further optimisation. This task is faced with several challenges in achieving a safe, reliable, and effective solution that provides a highly selective interface with sufficient isolation to minimise crosstalk. Of the various types of neural interfaces that have been developed for different applications and levels of invasiveness, this research focuses on the microchannel neural interfaces (MNI), which provide a high degree of isolation between channels, and hence selectivity. To address the challenges in manufacturing of high-density implants, an active solution is under development to limit the number of connecting wires by multiplexing many electrode sites on an application-specific integrated circuit (ASIC). The key functionalities implemented in the design of the ASIC include a neural recording unit with in-situ amplification to record biopotential signals of a sufficiently high quality, with an electrical stimulation unit, which provides simultaneous electrical stimulation to elicit or inhibit neural activity in the vagus nerve. In addition to the selection and optimisation of appropriate topologies for each circuit block to create a safe, reliable, and effective system, some factors were considered for the integration of the high voltage (HV) stimulation circuits and the low voltage (LV) recording blocks. Protection of the recording units during same-channel stimulation was achieved by signal blanking using an advanced technology to isolate the circuits when necessary. This technique was combined with automatic detection and reduction of stimulus artifacts for concurrent adjacent-channel stimulation and recording through pole shifting. Simulations of the composite neural signals superimposed by stimulus artifacts have shown a 54 dB artifact attenuation with the applied techniques. This novel feature aims to address the difficulties arising from the integration of HV stimulus units with the LV recording blocks in bidirectional systems to enable concurrent operation of the two with minimum impact on the safety of the electronic circuits as well as the quality of the recorded signal. |
| Exploitation Route | Although this research is aimed at recipients of a heart transplant, the active interface under development can be implemented for a wide range of applications involving neuromodulation of the peripheral nerves. For instance, stimulation of the vagus nerve, which is known as the 'wandering' nerve due to its extensive distribution to the thorax and abdomen, has shown numerous benefits in treating inflammatory diseases due to the cortical desynchronisation and anti-inflammatory properties of VNS as a therapeutic strategy. By designing a highly selective active neural interface, this research aims to enable further understanding of the physiological responses of the peripheral nerves to neuromodulation as well as the development of advanced bioelectronic solutions to complex physiological problems through addressing some of the current challenges in neural interfaces. |
| Sectors | Electronics,Healthcare |