Dielectric Elastomer Actuators, Neuromuscular Interfaces, and Foreign Body Response in Artiﬁcial Neuromuscular Prostheses: A Review of the Literature for an In Vivo Application

Adv. Healthcare Mater., 2021 · DOI: 10.1002/adhm.202100041 · Published: June 4, 2021

Simple Explanation

The review discusses the challenges and potential solutions for creating artificial muscles that can be controlled by the nervous system to replace lost or dysfunctional human muscle. Dielectric elastomer actuators (DEAs), which function as capacitors, are presented as a promising technology for artificial muscles due to their mechanical performance being similar to human muscle in vitro. The review focuses on improving the actuation properties of elastomers, integrating the nervous system with the artificial muscle, and reducing the foreign body response to make artificial neuromuscular prostheses a reality.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Review Article

Key Findings

1
Dielectric Elastomer Actuators (DEAs) with nanostructured carbon electrodes offer fast response times, long lifetimes, good reliability, high energy efficiencies, and large strains, making them suitable for artificial muscle applications.
2
Seamless integration of graphene with peripheral nerves is technically possible, but the nerve potential difference is insufficient to actuate a dielectric elastomer, necessitating amplification systems.
3
Strategies to reduce the foreign body response (FBR) include choosing the right size and shape of the device, hiding biomaterials with ECM or zwitterionic materials, and releasing antifibrotic agents.

Research Summary

This review explores the potential of dielectric elastomer actuators (DEAs) as artificial muscles controlled by the nervous system, highlighting their mechanical and electrical performance advantages. It addresses key challenges such as improving DEA actuation properties, achieving seamless or wireless integration with the nervous system, and mitigating the foreign body response (FBR). The review concludes that combining mechanical, electrical, and biological solutions may soon make artificial neuromuscular prostheses a reality in surgical practice.

Practical Implications

Clinical Applications

Neuromuscular prostheses could replace natural muscle in cases of musculoskeletal oncological impairments, neuromuscular diseases, traumas, and spinal cord injuries.

Material Selection

Silicone DEAs with CNT electrodes are promising, requiring further optimization of elastomer composition and wireless amplification systems to enhance electrical compatibility.

Biocompatibility

Reducing FBR is crucial, with strategies including optimized device design, ECM or zwitterionic coatings, and localized delivery of antifibrotic agents.

Study Limitations

1
Mechatronic compatibility between the natural nerve and the DEA is still a major limitation for clinical application.
2
There is a lack of long-term data on the effectiveness of anti-fibrotic drugs and pharmaceuticals in reducing FBR for implanted muscular prostheses.
3
The high voltages needed for current DEAs could result in harmful conditions for soft tissue and for the patient.

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