Objectives. Our ultimate goal is to develop, an in vivo peripheral nerve interface with long term stability for coupling severed peripheral nerve to prosthetic devices. We assemble biological materials within an alloplastic pouch to create the “living interface” for efferent and afferent communication by peripheral nerves. Our present purpose is to determine if regenerating nerve fibers successfully innervate myoblasts and create functional connections with the  biosynthetic “living interface” (LI) in vivo.  

Methods. In a rat model of peroneal nerve injury, we implanted biologically derived acellular muscle (AM) scaffolds (13x7x10mm) which were repopulated with autogenous myoblasts and myotubes (LI elements). In half of the groups (AM+DOT), the myoblast populated AM was coated with an electrically conductive polymer, poly(3,4-ethylenedioxythiophene)(PEDOT). The myoblast populated scaffolds were coapted to the proximal end of the divided peroneal nerve. The LI elements were enclosed in a thin permeable 20mm long silicone pouch. LI were allowed to mature in rats for up to 114 days. The LI were then prepared for histology.

Results. Within the LI, myoblasts matured into muscle, nerve fibers sprouted, muscle fibers were reinnervated, and angiogenesis occurred. Spontaneous EMG potentials were detected from the LI in vivo. Sensory stimulation (light touch) of the paw resulted in EMG recordings from the distal end of the AM and AM-DOT LI (Fig 1). Proximal stimulation of the peroneal nerve resulted in efferent motor action potentials detectable in the distal end of the LI.  A Prussian blue stain for acetylcholinesterase confirmed the formation of neuromuscular junctions within the LI.

	Figure 1. Electrophysiology example traces for “Living Interfaces”

 

 
Conclusion. Transected peripheral nerves innervate myofibers within a “LI” in the presence or absence of PEDOT. The LI is capable of short term stability and relays both motor and sensory potentials. Incorporating transmitter capabilities into the LI assembly and maturation is our next step.

The views expressed in this work are those of the authors and do not necessarily reflect official Army policy. This work was supported by the Department of Defense Multidisciplinary University Research Initiative (MURI) program administered by the Army Research Office under grant W911NF0610218.