|
1
|
Liu F, Habibollahi M, Wu Y, Neshatvar N, Zhang J, Zinno C, Akouissi O, Bernini F, Alibrandi L, Gabisonia K, Lionetti V, Carpaneto J, Lancashire H, Jiang D, Micera S, Demosthenous A. A multi-channel stimulator with an active electrode array implant for vagal-cardiac neuromodulation studies. Bioelectron Med 2024; 10:16. [PMID: 38970083 PMCID: PMC11227238 DOI: 10.1186/s42234-024-00148-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/21/2024] [Indexed: 07/07/2024] Open
Abstract
BACKGROUND Implantable vagus nerve stimulation is a promising approach for restoring autonomic cardiovascular functions after heart transplantation. For successful treatment a system should have multiple electrodes to deliver precise stimulation and complex neuromodulation patterns. METHODS This paper presents an implantable multi-channel stimulation system for vagal-cardiac neuromodulation studies in swine species. The system comprises an active electrode array implant percutaneously connected to an external wearable controller. The active electrode array implant has an integrated stimulator ASIC mounted on a ceramic substrate connected to an intraneural electrode array via micro-rivet bonding. The implant is silicone encapsulated for biocompatibility and implanted lifetime. The stimulation parameters are remotely transmitted via a Bluetooth telemetry link. RESULTS The size of the encapsulated active electrode array implant is 8 mm × 10 mm × 3 mm. The stimulator ASIC has 10-bit current amplitude resolution and 16 independent output channels, each capable of delivering up to 550 µA stimulus current and a maximum voltage of 20 V. The active electrode array implant was subjected to in vitro accelerated lifetime testing at 70 °C for 7 days with no degradation in performance. After over 2 h continuous stimulation, the surface temperature change of the implant was less than 0.5 °C. In addition, in vivo testing on the sciatic nerve of a male Göttingen minipig demonstrated that the implant could effectively elicit an EMG response that grew progressively stronger on increasing the amplitude of the stimulation. CONCLUSIONS The multi-channel stimulator is suitable for long term implantation. It shows potential as a useful tool in vagal-cardiac neuromodulation studies in animal models for restoring autonomic cardiovascular functions after heart transplantation.
Collapse
Affiliation(s)
- Fangqi Liu
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Maryam Habibollahi
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Yu Wu
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Nazanin Neshatvar
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Jiaxing Zhang
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Ciro Zinno
- BioRobotics Institute, Scuola Superiore Sant'Anna (SSSA), 56025, Pisa, Italy
| | | | - Fabio Bernini
- BioMedLab, Scuola Superiore Sant'Anna (SSSA), Pisa, Italy
| | - Lisa Alibrandi
- BioMedLab, Scuola Superiore Sant'Anna (SSSA), Pisa, Italy
| | | | | | - Jacopo Carpaneto
- BioRobotics Institute, Scuola Superiore Sant'Anna (SSSA), 56025, Pisa, Italy
| | - Henry Lancashire
- Department of Medical Physics and Bioengineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Dai Jiang
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Silvestro Micera
- BioRobotics Institute, Scuola Superiore Sant'Anna (SSSA), 56025, Pisa, Italy
| | - Andreas Demosthenous
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| |
Collapse
|
|
2
|
Shah JV, Collar BJ, Ditslear E, Irazoqui PP. An ASIC System for Closed-Loop Blood Pressure Modulation through Right Cervical Vagus Nerve Stimulation. IEEE Trans Biomed Eng 2022; 69:3021-3028. [PMID: 35294339 DOI: 10.1109/tbme.2022.3159597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Heart disease is the leading cause of death worldwide. Hypertension is an important precursor and the most common risk factor to heart failure. While some patients can control their high blood pressure with pharmaceuticals, many suffer from resistant hypertension, where antihypertensive medications do not achieve the desired outcome. Electrical stimulation is an emerging therapy to modulate blood pressure and integrating it with closed-loop feedback can improve blood pressure control. METHODS We design and fabricate two application-specific integrated circuits (ASICs) for stimulation and pressure sensing using TSMC's 180 nm MS RF G process. We create a closed-loop system by integrating the ASICs with a microscale pressure sensor and a custom-built Python script and test the full system in six Long Evans rats using vagus nerve stimulation. RESULTS After calibration and benchtop verification, we prove the functionality of the system in lowering, and maintaining a desired blood pressure in vivo. The system effectively monitors pressure and stimulates when that pressure exceeds the user-determined threshold. CONCLUSION By combining this stimulation therapy with a pressure sensor, we present a novel closed-loop, electroceutical system that has the potential to monitor and modulate blood pressure. SIGNIFICANCE We present a drug-free, potentially side-effect-free electroceutical therapeutic for managing resistant hypertension.
Collapse
|