Research Article
Development of a Regenerative Peripheral Nerve Interface for
Control of a Neuroprosthetic Limb
Melanie G. Urbanchek,
1
Theodore A. Kung,
1
Christopher M. Frost,
1
David C. Martin,
2
Lisa M. Larkin,
3,4
Adi Wollstein,
1
and Paul S. Cederna
1,4
1
Section of Plastic and Reconstructive Surgery, Department of Surgery, University of Michigan Health System, Ann Arbor,
MI 48109-5463, USA
2
Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716-1501, USA
3
Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-2200, USA
4
Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI 48109-2110, USA
Correspondence should be addressed to Melanie G. Urbanchek; melurban@umich.edu
Received 7 January 2016; Revised 5 April 2016; Accepted 17 April 2016
Academic Editor: Antonella Motta
Copyright © 2016 Melanie G. Urbanchek et al. Tis is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Background. Te purpose of this experiment was to develop a peripheral nerve interface using cultured myoblasts within a
scafold to provide a biologically stable interface while providing signal amplifcation for neuroprosthetic control and preventing
neuroma formation. Methods. A Regenerative Peripheral Nerve Interface (RPNI) composed of a scafold and cultured myoblasts
was implanted on the end of a divided peroneal nerve in rats ( = 25). Te scafold material consisted of either silicone mesh,
acellular muscle, or acellular muscle with chemically polymerized poly(3,4-ethylenedioxythiophene) conductive polymer. Average
implantation time was 93 days. Electrophysiological tests were performed at endpoint to determine RPNI viability and ability
to transduce neural signals. Tissue samples were examined using both light microscopy and immunohistochemistry. Results. All
implanted RPNIs, regardless of scafold type, remained viable and displayed robust vascularity. Electromyographic activity and
stimulated compound muscle action potentials were successfully recorded from all RPNIs. Physiologic eferent motor action
potentials were detected from RPNIs in response to sensory foot stimulation. Histology and transmission electron microscopy
revealed mature muscle fbers, axonal regeneration without neuroma formation, neovascularization, and synaptogenesis. Desmin
staining confrmed the preservation and maturation of myoblasts within the RPNIs. Conclusions. RPNI demonstrates signifcant
myoblast maturation, innervation, and vascularization without neuroma formation.
1. Introduction
Breakthroughs in robotic technology have facilitated the
advent of upper extremity prosthetic devices which have the
capability to emulate the functions of a native extremity.
However, realization of the full potential of these devices has
been hindered by the lack of an optimal interface between
the patient and the artifcial limb. Tis crucial interface must
permit reliable transmission of both eferent motor com-
mands and aferent sensory signals of sufcient amplitude
to be detectable above the inherent electrical noise. One of
the more popular strategies to achieve prosthetic control
involves a variety of experimental intraneural or epineu-
ral electrodes placed directly within or on the epineurial
surface of peripheral nerves within the residual limb [1].
Tis technique is particularly attractive because a signifcant
amount of axonal sorting and organization occurs within
peripheral nerves; therefore, directly interfacing with residual
peripheral nerves provides greatly increased signal specifcity
as compared to other types of control systems including
brain interfaces. However, while many types of peripheral
nerve interfaces (PNIs) have been studied and successfully
utilized to transduce eferent motor action potentials, they
are limited by their lack of long-term stability. Te major
design concern is to provide a sufciently robust interface
capable of detecting physiologic action potentials while
limiting the axonal damage and foreign body reaction which
Hindawi Publishing Corporation
BioMed Research International
Volume 2016, Article ID 5726730, 8 pages
http://dx.doi.org/10.1155/2016/5726730