Building a Digital Nervous System: Bioengineering Neuromuscular Interfaces for Biohybrid Brain-body Closed-loop Neural Prostheses
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Herrera-Arcos-gherrera-PHD-MAS-2026-thesis.pdf
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73a7192c9488611a291597270123ace0
Author(s)
Herrera-Arcos, Guillermo
Advisor(s)
Herr, Hugh
Date Issued
February 2026
Publisher
Massachusetts Institute of Technology
Abstract
Neural prostheses have demonstrated the ability to artificially control the nervous system towards neurological recovery. However, the current neuroprosthetic paradigm relies solely on synthetic electronic components for neural control, limiting precise neural targeting and hence hindering therapeutic impact. On the stimulation front, the standard technique to artificially stimulate neuromusculature, functional electrical stimulation (FES), cannot selectively activate neural structures, resulting in poor control and rapid fatigue, limiting chronic neuromodulation therapies and implantable organ actuation. On the sensing front, obtaining high-fidelity real-time neuromuscular states such as force, which are critical for closed-loop neural prostheses, remains elusive. In an alternative paradigm described in this dissertation, neuromuscular components are engineered at different scales, from the molecular to the organ scale, and interfaced with electronic components, to achieve augmented stimulation, sensing, and closed-loop control capabilities, realizing the potential of chronic closed-loop neuromodulation of brain-body circuits. Spanning genetic, regenerative, and bioelec- tronic approaches for artificial neural stimulation, implantable magnetic systems for wireless neuromuscular sensing, and model-based closed-loop control policies, this dissertation builds a platform for the digital control of organs to reestablish brain-body communication in neurological conditions.
In the first part of the dissertation, we present an optogenetic system that shows motor units can be recruited naturally for force production. Leveraging this mecha- nism, we designed a closed-loop system that enabled continuous control of skeletal muscle with high fidelity and without inducing fatigue. To advance the translational of peripheral optogenetic therapies, in the second part, we present a minimally im- munogenic transduction strategy to express optogenetic molecules in the periphery for long-term neuromodulation. We show that direct neural transduction enables chronic optogenetic expression in peripheral nerves. In the third part, we present the design of an implantable biohybrid actuator based on a regenerative approach to engineer motor recruitment. We demonstrate that sensory neurons can establish cholinergic synapses with muscle fibers and the axonal architecture of sensory nerves normalizes activation thresholds. Leveraging this mechanistic discovery, we show fatigue-resistant control of the actuator under FES, enabling the design of biohy- brid organ systems. For the fourth part, we present a minimally-invasive wireless sensing modality that estimates neuromechanical force by tracking tendon dynamics in real-time. The system combines chronically implanted magnetic beads in tendon tissue with a skin-mounted magnetometer sensing array. We also present a system for wireless detection of muscle activation by measuring magnetic flux changes resulting from muscle vibrations of implanted magnetic beads. For the fifth part, we present a fully-implantable peripheral bioelectronic platform for chronic wireless sensing, stim- ulation, and adaptive closed-loop control of individual muscle neuromechanics. We demonstrate submillimeter-accuracy closed-loop neuromechanical control under sus- tained and cyclic reference trajectories, as well as precise modulation across changing dynamic mechanical demands.
Altogether, this dissertation builds a biohybrid platform spanning neural stimula- tion, sensing, and closed-loop neuromodulation technologies, and lays the groundwork for high-performance closed-loop neural prostheses and bioelectronic therapies for chronic neuromodulation of brain-body circuits.
MIT Department
Program in Media Arts and Sciences (Massachusetts Institute of Technology)
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