Microscale Electrode Implantation during Nerve Repair

Abstract

Background Our goal is to develop a peripheral nerve electrode with long-term stability and fidelity for use in nerve-machine interfaces. Microelectromechanical systems (MEMS) use silicon probes that contain multi-channel actuators, sensors, and electronics. We tested the null hypothesis that implantation of MEMS probes do not have a detrimental effect on peripheral nerve function or regeneration. Methods A rat hindlimb, peroneal nerve model was utilized in all experimental groups: a) intact nerve (Control, n= 10); b) nerve division and repair (Repair, n= 9); and c) Nerve division, insertion of MEMS probe, and repair (Repair + Probe, n=9). Nerve morphology, nerve to muscle compound action potential (CMAP) studies, walking tracks, and extensor digitorum longus (EDL) muscle function tests were evaluated following an 80 day recovery. Results Repair and Repair + Probe showed no differences in axon count, axon size, percent non-neural area, CMAP amplitude, latency, muscle mass, muscle force, or walking track scores. Though there was some local fibrosis around each MEMS probe, this did not lead to measurable detrimental effects in any anatomic or functional outcome measurements. Conclusions The lack of a significant difference between Repair and Repair + Probe groups in histology, CMAP, walking tracks, and muscle force suggests that MEMS electrodes are compatible with regenerating axons and show promise for establishing chemical and electrical interfaces with peripheral nerves.

A Review of Organic and Inorganic Biomaterials for Neural Interfaces

“…[149] Among these polymers, poly(pyrrole) (Ppy), poly(aniline) (PANI), poly(thiophene) (PT), and poly(3,4-ethylenedioxythiophene) (PEDOT) (Figure 6a), and some of their derivatives have received more attention for biomedical applications, [146,149–151] especially neural interfaces [25,32,35,37,38,52,57,132,140,146,147,152–178] since these CPs exhibit good biocompatibility, [149,177,179] excellent electrical conductivity, and ease of synthesis. [134,136] Ppy is the most commonly utilized CP for neural applications because of the superior water solubility of the pyrrole monomer.…”

Lower Extremity Allotransplantation: Are We Ready for Prime Time?

“…[33][34][35][36][37][38][39] Alternative solutions include intracranial electrode placement for brain control [40][41][42][43][44][45] and highly selective peripheral nerve interfaces. 33,[46][47][48]…”

Biocatalytic Redox Reactions for Organic Synthesis: Nonconventional Regeneration Methods

“…Conducting polymers such as poly(pyrrole) (PPy) and poly(3,4‐ethylenedioxythiophene) (PEDOT) have been considered for biomedical applications,26, 27 in particular, neural interfaces28–33 due to the following four characteristics: 1) their organic nature,26 2) their response to electrical stimuli (volume, color, and wettability changes),34 3) their ability to be functionalized with biomolecules,35 and 4) their ionic and electronic conductivity 26, 36, 37. PEDOT has an excellent chemical stability in aqueous solution at room temperature even at higher temperature, which originates from the stabilizing effect on the positive charges by sulfur and oxygen 38.…”